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The free acid content of 2,4-D and 2,4,5-T esters and formulations is determined by titration to pH 7.0, using a pH meter. Average recoveries and standard deviations for 9 collaborators, analyzing 4 samples containing different amounts of the esters, were 0.2067± 0.0201 and 0.3778±0.0245 for 2,4-D ester and 0.6208±0.0555 and 1.4622±0.1356 for 2,4,5-T ester. The method has been adopted as official first action.

The sample of superphosphate is extracted with water, and the solution titrated with carbonate-free sodium hydroxide in two stages with appropriate indicators. The first stage gives the free acid, and the second stage an approximate result for the primary calcium phosphate, Ca(H2PO4)2. A suitable volume of the sodium hydroxide is then titrated with the superphosphate solution, giving a reading from which a more accurate value for the primary calcium phosphate can be obtained. The total soluble phosphate determined in this way agrees well with that found by gravimetric analysis.

(1837). Process for ink devoid of free acid. The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science: Vol. 11, No. 67, pp. 324-325.

1. Sections of rice, wheat and mint plants were soaked in acidic buffer solutions containing some different cations. It was found that the solutions containing cations kept their pH, not to decrease highly and the less its hydration was, the more largely it was influenced. 2. In the mint rhyzome, the absorption of free acid did not decrease by addition of cations, but the cations of smaller hydration were absorbed more easily, and their respirations also did not decrease. It was confirmed that the pH value depended also on the respiration. 3. In comparing among various crop plants, the more easily its pH decreased, the more easily its respiration decreased. Sometimes judging from the grade of acid-resisting ability, pH valuet seemed to be influenced more largely than Al in some crop plants.

During the course of an investigation by one of us1 of the effect of vagal stimulation on the production of gastric secretion, it was observed that artificial ventilation considerably diminished the volume of the secretion. To ascertain the factors involved in this effect the following experiments were performed on dogs anesthetized with a chloralose and urethane mixture given intravenously.1. Gastric secretion was obtained by vagal stimulation in the neck. The right and left nerves were stimulated alternately for 10 minutes each throughout the experiment. 2. Hyperventilation was applied. 3. Hyperventilation was continued at the same rate using an artificial air-carbon-dioxide mixture.A study was made of the gastric juice, the collecting tubes being changed every 10 minutes. Total and free acid were determined by titration, and total chlorides by the method of Wilson and Ball.2 The arterial (carotid) plasma carbon dioxide content was determined by the volumetric method of Van Slyke, and the plasma pH by t...

A differential thermal analytical technique is described for the quantitative determination of stearic acid in aluminium stearate. The technique is potentially useful for the rapid determination of the free acid in its metal soap.

Free phthalic acid is a common impurity in samples of recognised analytical grade potassium hydrogen phthalate. If the pH error of a 0.05 m solution is to be –0.001 or less the free acid content must not exceed 0.025%m/m. A simple ether extraction-ultraviolet spectrophotometric procedure for determining the free phthalic acid content has been developed. The method is capable of detecting less than 0.0003%m/m of free acid and is reproducible to ±8%. A close correlation between the free acid content, the pH and the acidimetric purity has been confirmed.

A crystal structure analysis of the free acid form of the antibiotic X-206 has resulted in corrections to the previously published structure which was based on an X-ray analysis of its silver salt.

The synthesis of [4-3H]glutamate involved regioselective tritiation of monomethyl succinate, a two-step selective conversion of its free acid function into an aldehyde, and its subsequent conversion by the Strecker reaction into the corresponding α-aminonitrile and hence to the target tritiated glutamate.

Single crystals of the free base of guanosine 5′-monophosphate were X-irradiated at 10 and at 65 K and investigated between these temperatures and room temperature using K-band ESR and ENDOR spectr...

Mixtures of diphenyl sulphoxide and acid chlorides behave as chlorinating agents towards suitable substrates. Diphenyl sulphide, 4-chlorodiphenyl sulphide, and the free acid are liberated.

The first essential, naturally, is to establish the fact that achlorhydria exists. The only reliable proof of this is supplied by fractional gastric analysis. A single extraction of stomach contents will not suffice. The gastric secretion must be watched throughout at least two hours after a test meal, for no free acid may be found at the end of forty-five minutes or one hour and yet may appear later on. No symptoms prove or disprove the existence of achlorhydria. Nothing in the physical examination alone determines the activity of the gastric secretion. Even roentgen-ray reports cannot be depended on to settle this question. Only fractional gastric analysis is conclusive. Once it is determined that the stomach secretes no free hydrochloric acid, a starting point has been found from which to proceed to a diagnosis. We are then in a position to ask what conditions cause achlorhydria or with what diseases

This is a report of measurement of gastric acidity in the prematurely born baby during the first 10 days of life. The studies heretofore reported have been in newly born full-term infants. It has been established that nearly all full-term babies secrete gastric acid within three to six hours of birth. Indeed the majority of investigators (Hess, 1913; Griswald et al., 1925; Chievitz, 1922)1-3do not believe that congenital achlorhydria exists, and, in fact, they believe that free hydrochloric acid is always present in the gastric juice of the unfed infant at birth. However, Strauss and Castle (1932)4and Miller ( 1941 )5found achlorhydria in the newly born infants, but only in those babies whose mothers were achlorhydric. Miller (1941)5further reported that free acid varied directly with the birth weight; i.e., the lower the birth weight, the lower the gastric acidity, and that there was no

UNDER the humid climate of northern and western Britain organic materials often accumulate as mor 1 humus layers on well-drained woodland soils or as bog peats in wetter locations. Both types of humus are characteristically very acid, and this communication examines the possibility that sulphuric acid is mainly responsible for their low pH values.

Bilirubin is the most important of the bile pigments, the remaining two, biliverdin and bilicyanin, being oxidation products of bilirubin. It occurs in the blood as an acid and is therefore capable of forming salts differing in properties from the free acid. It is produced as the result of the break-down of the red cells of the blood; this probably occurs in the ramifications of the reticulo-endothelial system and has been shown to be almost entirely extrahepatic. 1 The bilirubin so produced is carried in the blood stream as a colloidal suspension and excreted from the liver into the bile passages. Before this excretion occurs, it undergoes a transformation in the liver cells from the form in which it is found in the blood to that in which it appears in the bile. The exact nature of this conversion is a matter of dispute, but the recent work of Collinson and

The ideal internal urinary antiseptic must be a drug which is chemically stable, nontoxic, and nonirritating to the lower urinary tract; which is antiseptic in high dilution (in urine, as well as in water), and which is eliminated unchanged in high percentage by the kidney. There is no such drug known. A consideration of the properties possessed by phenolsulphonephthalein, however, shows that this compound comes very close to filling all these requirements. Phenolsulphonephthalein is chemically stable, nontoxic and nonirritating, and is eliminated by the kidney with incredible rapidity and completeness; but it has no antiseptic properties, excepting in water in its free acid form. (Clinically it is used as the monosodium salt.) This remarkable compound, synthesized in 1898 by Sohon,1at Remsen's2suggestion, investigated later in Abel's3laboratory, and introduced into clinical use by Rowntree and Geraghty4twelve years later, has become the basis of the

Last winter during my service at Blockley a patient was admitted suffering from severe intestinal colic due to chronic lead poisoning. In the hope of obtaining some information on the nature of the colic, a test-meal was obtained, and the findings were so interesting that, at my suggestion, my resident physician, Dr. John Speese, obtained test-meals of all the cases of lead poisoning that were available during the rest of the winter. The results were so nearly uniform that it seems unlikely that a more extended series of investigations will show any material difference. The technic was as follows: Usually with, sometimes without, a preliminary washing, the patient was given a test-meal of two slices of bread and about twelve ounces of water. One hour after the patient commenced eating, the stomach contents were withdrawn by aspiration, measured and tested for free acid with Congo red, then filtered and examined.

A NUMBER OF YEARS have passed since Segal 1 and his group originally described the use of a cation exchange resin coupled with a quinine compound to determine the presence or absence of achlorhydria. Today the modified "tubeless test meal" using azuresin (Diagnex) has become an accepted method of detecting achlorhydria. Many reports in the literature 2-5 have testified to its value in screening tests done both as an office procedure or in the hospital, with various authors reporting a range of accuracy from 85 to 100%, when compared with the results of controlled gastric intubation. Rodman 6 found that the incidence of 3.5% of false positives (i.e., the tubeless gastric analysis indicated free hydrochloric acid when the gastric aspirate showed no free acid), in his series correlated well with other reports. No case in a review of the available literature has been found where the presence of intestinal diverticula

In examining a great number of patients with peptic ulcer or with subtotal gastrectomies, one is often faced with the problem of an apparently complete anacidity and a lack of response of the acid secretion of the stomach even to histamine, in patients who complain about heartburn, belching of sour material, and the like. Sometimes examination of the stomach contents of such persons right after sampling but before filtration reveals a strong positive reaction for free acid (Topfer's reagent) on the surface of the mucous material only. This soon disappears, especially after filtration. Such cases cannot be called anacid but under the conditions of an ordinary stomach test would so appear. Evidently the little free hydrochloric acid that is present combines quickly with the mucus, which in most of these cases is abundant. In other cases, regurgitation from the duodenum is the neutralizing factor. We therefore devised a method by

Kesten and Slatkin 1 confirm the work of Rothman and Rubin 2 on the excellence of paraaminobenboic acid as a sunscreen. Rothman, in discussing this paper, comments on the difficulty of making smooth creams with the free acid. For some time, I have been using the following cream, which is a smooth elegant preparation of 15% paraaminobenzoic acid. It consists of 4.5 cc. of paraaminobenzoic acid, 6.0 cc. of distilled water, 6.0 cc. of hydrophilic ointment, and add vanishing cream to make 30.0 cc. The pharmaceutical instructions are as follows: Levigate the paraaminobenzoic acid with water to a smooth paste. Add hydrophilic ointment, and finally add the required amount of vanishing cream. The vanishing cream used may be that of any reputable cosmetic firm. As Rothman points out, this preparation is an excellent sunscreen and it is much less sensitizing than the esters of paraaminobenzoic acid.

On the continent of Europe this subject has been investigated chiefly by Faber, Ewald, Zadek, Weinberg and others, Faber expressing as his opinion that achylia gastrica is generally preceded by a chronic gastritis. In England Hurst was the chief exponent; he also showed by means of the fractional test meal that the absence of free hydrochloric acid in pernicious anemia invariably persists throughout the whole period of digestion, whereas in other conditions, such as cancer of the stomach, it is not uncommon to find a small quantity of free acid in one or more of the fractions. The significance of this achylia was pointed out by Castle, 1 who in a series of experiments with normal gastric juice and beef muscle, administered in different ways to patients with pernicious anemia, endeavored to establish an etiologic relationship between achylia gastrica and pernicious anemia. This constant achylia and the facts concerning the familial

IN the course of a study of the water sorption of aluminium soaps, Shreve, Pomeroy and Mysels1 found that pure aluminium laurate which had been dried in vacuo over phosphorus pentoxide at room temperature gave 2·5 ± 0·4 per cent of water when examined with the Karl Fischer reagent. They maintained, consequently, that the reagent gives misleading results because, under the conditions of the determination, soap molecules react with each other, or with free acid, to give water, thus

A comparative study was made of certain indicators which have been used in the titration of gastric juice for free and total acidity and for the colorimetric determination of the H ion concentration of the same. The findings apply particularly to titrations where small amounts of gastric juice are available and many determinations must be carried out.Phenolphthalein was the most satisfactory indicator for total acidity in spite of the fact that values obtained with it are slightly high, because the end point is definite and speed and accuracy are attainable with its use while the use of litmus or alizarin requires more time and the end points cannot be determined with accuracy.For the titration of free acidity the iodometric method was found most useful. In the higher acidities dimethylaminoazobenzene may be used with an equal degree of accuracy and may be preferred where much starch is present. Congo red possessed no advantages over the foregoing in the determination of free acid but gives high results a...

Salts of 2,3,5,6-tetrahydroxypiperazine-1,4-disulphonic acid were prepared by the addition of aqueous glyoxal to sulphamic acid in the presence of base. The free acid was not isolated. 2,3,5,6-Tetra-acetoxy-1,4-dinitropiperazine and 2,5-diacetoxy-3,6-dinitrato-1,4-dinitropiperazine were prepared by the action of nitric acid and acetic anhydride on the tetrahydroxypiperazine salts.

We have recently seen a case of dermatitis venenata due to potassium undecylenate. We have been unable to find any previous report of dermatitis venenata due to undecylenic acid or its salts. In view of the widespread use of these substances in the local treatment of dermatophytosis, we feel that the possibility of one of these agents producing a contact dermatitis should be made known. REPORT OF A CASE J. B., a 52-year-old white man, had intermittent scaling and itching between the toes. He applied timofax® ointment (a cream containing 10% undecylenic acid as free acid and potassium salt) to the feet on two successive days, and on the third day the dorsa of the feet became erythematous, edematous, and exudative. Application of the ointment was discontinued, and there was gradual healing with soothing local therapy. There were slight residual erythema and fissuring at the base of the left

The potential of certain aromatic azides as photosensitive protecting groups has been explored. With alkyl or acyl derivatives of β-(o-azidophenyl)ethyl alcohol photolysis yields indole and the corresponding alcohol or acid. Whereas o-azidobenzyl benzoate is photolysed in protic solvents to give polymers and little of the free acid, derivatives of 5-azido-4-hydroxymethyl-1-methoxynaphthalene are more efficiently photolysed with release of the protected group.

The structure of the metal-free acid of the antibiotic X-537A has been determined using a bromo-derivative and reveals a dimer enclosing a water molecule.

With the introduction of histamine as a stimulus to gastric secretion it became necessary to revise preexisting ideas about gastric anacidity, since it was found that many people who failed to secrete free acid after a meal of bread, gruel or alcohol gave a normal or nearly normal response after stimulation by the more powerful agent. In fact, total inability of the stomach to secrete acid now appears to be an uncommon condition, which is in contrast to the older observations that indicated that anacidity was to be found in from 5 to 40 per cent of people without obvious gastric disease. 1 During the past few years we have studied the gastric secretion of about five hundred persons, with and without digestive symptoms, by means of the histamine test. Failure to produce free hydrochloric acid (when tested with dimethyl-amino-azobenzene) occurred in the following conditions: (1) invariably in cases of

A STRONG solution of pure cytochrome c obtained by the method which we have previously described1 shows in the oxidized state an absorption spectrum of the parahaematin type. In a very much higher concentration and in a thick layer this compound reveals the two additional feeble absorption bands at about 695 mμ and 625 mμ discovered by Yakushiji2. The absorption spectrum of oxidized cytochrome c changes with the hydrogen ion concentration2,3. In this respect, cytochrome c resembles other trivalent haeematin compounds such as methaemoglobin, parahaematin and haeematin. It is known, for example, that a parahaematin compound has a characteristic absorption spectrum only within a certain limited range of hydrogen ion concentration4. On acidifying it or on making it alkaline the absorption spectrum of parahaematin changes respectively to those of free acid and free alkaline haematins.

The literature contains reports on nearly 1,000 patients treated with sulfadiazine. Only 2 instances have been recorded in which urinary suppression followed the administration of this compound. In both cases cystoscopy and pelvic lavage promptly relieved the renal failure. 1 In contrast to these clinical reports, which suggest a low toxicity of sulfadiazine, observations on experimental animals are less optimistic. Lehr and Antopol 2 found that, in albino rats, sulfadiazine may produce acute precipitation of the free acid in the renal tubules, and because of the poor solubility of the drug severe degeneration of the tubular epithelium may result. Gross, Cooper and Hagan 3 gave sulfadiazine in different doses to mice and rats. Of 70 mice, 15 died following the medication. In one third of all the animals almost all collecting tubules were blocked by crystalline masses. In about one fifth of the animals crystals were found also in the

The excellent results obtained after partial gastrectomy for gastric and duodenal ulcers have been attributed to the fact that in a large percentage of cases an anacidity is produced. Thus, Lorenz and Schur 1 found that 75 per cent of patients were rendered anacid. In this hospital Lewisohn 2 reported 77 per cent of anacidities. Similar results have been obtained by others. This study was prompted by three considerations. First, if 77 per cent of the patients were rendered anacid by the operation, why was not the same result obtained in the remaining 23 per cent? Second, some gastrojejunal and jejunal ulcers have recently been reported after partial gastrectomy. Did these occur in the cases in which acidity persisted? Third, since the absence of free acid in the stomach can be effected in various ways, what was the nature of the anacidity after partial gastrectomy? Hydrochloric acid is considered by

A chromatographic procedure for detecting 4-amino-3,5,6-tricholorpicolinic acid (picloram) residue to a sensitivity of approximately 0.05 ppm in soils is described. Picloram is extracted from soil as the free acid and methylated with boron trifluride-methanol reagent. Data indicate that the amount of herbicide which actually reaches the soil may only be 10% of that applied to dense stands of oak. Rainfall was an important factor in determining the movement and persistence of picloram. Picloram was detected to a depth of 24 in within 6 weeks after application. No detectable residues were found in the upper 24 in of soil after one year with rates as high as 8 lb/A.

The diagnosis of biliary tract infection by nonoperative means remains a practical clinical problem, notwithstanding improvements in diagnostic procedures. The fact that the duodenum is normally sterile and that bacteria of the biliary tract can be obtained with a duodenal tube has been known for many years. 1 Duodenal cultures consistent with those found in the biliary tract at operation can be obtained with an encapsulated duodenal tube. 2 Duodenal cultures, however, are influenced by the presence of free hydrochloric acid in the gastric contents because the free acid apparently has an inhibiting effect on the growth of bacteria in the stomach, duodenum and bile. 3 Cultures of the liver may be positive for pathogenic organisms in the normal person because some bacteria transmitted by the blood stream to the liver to be destroyed may survive. These are excreted into the bile ducts. There, however, they rarely produce pathologic changes

Fogelson 1 found that he could prepare from the gastric mucosa a neutral mucin which had a high combining power for free acid. Such a preparation has the requirements of an ideal antacid in that it does not markedly excite gastric secretion, is soothing or protective, and does not alter the body chemistry or disturb the gastro-intestinal tract. On feeding adequate quantities of this product to patients presenting peptic ulcer, Fogelson has obtained excellent preliminary results. It occurred to us that it would be decidedly significant to ascertain whether the administration of this mucin would prevent the occurrence of ulcers in the dog, which are known to arise spontaneously following certain experimental procedures. It has been shown that the exclusion of bile from the intestine may lead to the spontaneous development of single or multiple duodenal or gastric ulcers in the dog. Kapsinow 2 diverted the bile from the intestine

WE have now confirmed the accuracy of the structure (I) cooH.co.co.CHOH.CHOH.CH2OH which we had previously assigned to the first (reversible) oxidation product of ascorbic acid on the ground that it yields oxalic acid and trihydroxybutyric acid (l–threonic acid) on further oxidation1. The above formulation represents an open chain acid, but it is now evident that at the moment of formation the substance behaves as a lactone of (I) and not as the free acid. We have already advanced a constitutional formula for ascorbic acid (represented by (II) and its tautomerides) which shows the relationship between (I) and (II) to be as follows :2

Alkalis play a varying part in the different plans that have been advocated for the medical management of peptic ulcer. They are not used at all in some forms of treatment, while in other forms they are used in small quantities for short periods only. But it has remained for Sippy to work out a thorough, detailed method of using alkalis with ulcer-bearing patients, which is one of the most important parts of his form of treatment. He insists on the necessity of destroying the corrosive, disintegrating and digestive effect of the gastric juice, pointing out that it is best done by continuously neutralizing the free hydrochloric acid with alkalis; for the digestive properties of pepsin are lost in the absence of free acid. It is true that it is not yet known just what part the acidity of the gastric juice plays in the formation or the delayed healing

In this paper evidence will be presented which strongly indicates that the excessive use of caffeinecontaining beverages may contribute to the pathogenesis of "peptic" ulcer in the ulcer-susceptible individual, may aggravate an ulcer already existing and may render the therapeutic management of the condition more difficult. Preliminary studies on ulcer patients suggest the use of a caffeine test meal in the diagnosis of peptic ulcer based on the prolonged secretory curve when the response to caffeine is expressed as the total output of free acid. Additional evidence suggests that a prolonged gastric secretory response to caffeine may provide a method for the detection of those persons who are predisposed to the development of "peptic" ulcer. LITERATURE Smoking and the consumption of alcoholic beverages have been interdicted in the management of "peptic" ulcer patients by internists for many years. The consumption of caffeine-containing beverages has not, as a rule, been restricted

Two methods for detecting gastric achlorhydria, the conventional and the tubeless methods, were compared in a study of 114 hospital patients. Each patient had a disease that might be expected to interfere with the physiological mechanisms involved in the tubeless method. The fasting patients received 1.0 mg. of histamine phosphate subcutaneously to stimulate gastric secretion. After 45 minutes a urine specimen was obtained and a sample of gastric juice was removed for the conventional titration with dimethylaminoazobenzene (Topfer's reagent) as indicator. The patient then received 2 Gm. of a cation exchange resin (containing 90 mg. of azure A) with 240 ml. of water. Two hours later a second urine specimen was obtained for comparison with the first. Appearance of the dye in the second urine specimen, indicating the presence of free acid in the stomach, was correlated with the amount of acid disclosed by titration. Discrepancies between the results of the tube and the tubeless methods were found in 12 patients, 7 of whom had renal disease. In 102 patients the results of the two tests agreed. The simplicity of the tubeless method recommends it for use as an office procedure and in screening large numbers of patients.