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ALTHOUGH much has been written about the problematical coccoliths, the presence of these bodies in our coastal waters does not appear to have been recorded. Our observations on the minute marine organisms off this coast (South County Dublin) show that they abound both near the shore and outwards to the limits we have hitherto investigated—some three miles into the Irish Channel.

In the literature on osteomalacia, on multiple cystic tumors of bone and on parathyroid tumors, there is a clinical picture, found occasionally under all of these titles, which seems to deserve description as a separate clinical entity. The study of the case reported here first called our attention to this disease.A woman, aged 56, entered Barnes Hospital, Feb. 9, 1927, because of complete inability to walk, frequency of urination, and a swelling of the right forefinger. She had been strong and healthy during her childhood. She married at 22, but had never become pregnant. The patient lived with her husband on a small farm, where she worked hard. Some time in her girlhood she conceived a dislike for milk. She had other strong dislikes for food, which finally led her to adopt a diet that was extremely ill balanced. She was well, however, until the age of 38, at

I HAVE been making some observations on the locomotion of various insects, and find that in the case of those which move quickly the best method for observation is instantaneous photography. Instantaneous photographs of moving flies show that they move the front and hind leg of one side almost simultaneously with the middle leg of the other, while they stand on the other three. When the tripod which is moving has come to the ground, the other tripod is raised, and so on. The photographs show, however, that while no leg of one tripod ever moves simultaneously with any leg of the other, yet there is a succession in the movements of the legs of each tripod. The hind leg on one side is first moved, then the middle on the other, and when the hind leg has been moved forward and almost reached the ground, the front leg of that side is raised. The middle leg and the front leg of the opposite sides come to the ground almost simultaneously. It is usually just when the hind leg is reaching the ground, and the front leg is being raised, that the tripod on which the fly is resting thrusts the body forward. After the movement of each tripod there appears to be a short pause, during which all six legs are on the ground together.

When 2 cc. of 1% sodium bicarbonate is injected intraperitoneally in frogs there results, in about one-half hour, a disorder of the skeletal muscles characterized by fascicular twitching and dystonic movements. This was described as tetany by Ringer1in 1884. A similar condition develops about one-half hour after the intraperitoneal injection of 2 cc. of a neutral 5% solution of sodium phosphates. We have not been able to produce this type of reaction by administration of sodium oxylate, sodium fluoride, potassium chloride, calcium chloride, magnesium chloride, ammonium chloride or hydrochloric acid, even when these substances were given in doses large enough to cause complete prostration.We have studied the effect of all of these substances on the fatigue curve of the isolated gastrocnemius of the frog. The muscle was stimulated directly through silver chloride electrodes with faradic shocks delivered at the rate of 3 makes and breaks per second. Care was taken to have the stimuli always the same and strong enough so that the make shocks gave maximal contractions. The normal muscle when stimulated in this way responds at first with discrete contractions returning to the base line. After 15 or 20 seconds relaxation becomes delayed and fatigue contracture slowly develops resulting in a steadily maintained contracture of approximately the same height as the original discrete contraction.A muscle from a frog treated with a neutral solution of sodium phosphates responds in a very different manner. Even after the first contraction, relaxation is much delayed and the muscle remains shortened with contractions of small magnitude superimposed upon the contracture curve. When the stimulation is discontinued, relaxation is slow and imperfect.

PURIFIED haptoglobins of the three common genetic types (Hp 1–1, Hp 2–1 and Hp 2–2), after reductive cleavage with mercaptoethanol in the presence of urea, yield two classes of product (Smithies, O., Connell, G. E., and Dixon, G. H.; in preparation). One group of the cleavage products fails to migrate in acidic starch-gels (except in the presence of 8 M urea), and appears to be common to haptoglobin of all the genetic types. The other cleavage products, which migrate readily, differ according to the genetic type of haptoglobin. The homozygous type haptoglobin 1–1 gives a migrating product different from that obtained with haptoglobin of the other homozygous type 2–2 ; heterozygous haptoglobin gives both products.

We have synthesized a family of double-stranded cDNAs (ds cDNAs) using as a template the family of highly purified protamine mRNAs from rainbow trout testis. Individual pure protamine cDNA components were isolated by cloning this family of protamine ds cDNAs in a plasmid vector (pMB9). Clones containing protamine sequences were characterized by restriction mapping and by a positive hybrid-selected translation assay, which allowed us to correlate particular cDNAs with particular protein components. To allow more detailed comparisons, complete nucleotide sequences were determined for selected protamine clones. We have detected at least 5 distinctly different coding sequences, which nevertheless show at least 82% homology, and which have probably arisen by repeated gene duplication. These very highly conserved coding sequences do however contain a distinctly variable region near the 5′-end of the mRNA (N-terminus of the protein), corresponding to the major sites of serine phosphorylation. Since the amino acid sequences predicted by our DNA sequences were slightly different from those previously published (1), we have independently determined the amino acid sequences of protamine components CI, CII and CIII from our own source of trout testis. These new peptide sequences are completely consistent with those predicted by our nucleotide sequences. The 3′-untranslated regions of the protamine mRNAs are, surprisingly almost as highly conserved as the coding regions. Both coding and 3′-non-coding portions appear to be under a similar degree of selective pressure and evolutionary constraint to remain constant.

Poly(A)+ protamine mRNA's were isolated from rainbow trout testes and deadenylated by treatment with calf thymus RNase H. Four subcomponents of deadenylated PmRNA (PmRNA1–4) were purified by electrophoresis on a 6% polyacrylamide gel in 8 M urea. Translation of each PmRNA subcomponent in the wheat germ S-30 cell-free system showed that all subcomponents are biologically active but each codes for two or more protamine polypeptides suggesting molecular heterogeneity. However, the deadenylated mRNA's can be categorized into two groups based on the spectrum of protamines whose synthesis they stimulate.

We have determined the fraction of polyadenylated cytoplasmic RNA from trout testis complementary to unique and repetitive DNA. Some 21% of the cDNA probe representative of this RNA population renatures with rapid kinetics, characteristic of repetitive sequences. The major proportion of the cDNA renatures with unique sequence DNA. Experiments with fractionated cDNA probes allow us to conclude that, in trout testis, the most abundant polyadenylated mRNAs are not preferentially transcribed from repetitive DNA, as it has shown to be the case in two eukaryotic cell lines.Treatment of trout testis nuclei with DNase I,under conditions in which 10% of the total DNA is digested, preferentially depletes the DNA of sequences being transcribed into polyadenylated mRNA. These data confirm the results of H. Weintraub and M. Groudine [(1976)Science 193,848–856] and those of A. Garel and R. Axel [(1976) Proc. Natl. Acad. Sci. U.S.A. 73,3966–3970] and suggest that the conformation of DNA in the active genes of chromatin is such that it is more susceptible to digestion by DNasel.

During the final stages of spermatogenesis in rainbow trout a dramatic increase in the level of histone H4 hyperacetylation is observed which is closely correlated with the replacement of histones by protamines. In order to understand further how H4 hyperacetylation might assist in protamine replacement of the histones, we have investigated the effect of H4 hyperacetylation on chromatin structure in trout testes actively undergoing the replacement process. Long chromatin fragments enriched in hyperacetylated H4 have been isolated and characterized. Evidence is presented that hyperacetylated H4 is clustered in certain regions (domains) of late stage testis chromatin and within these domains the chromatin exhibits an altered, highly relaxed structure which is believed to be the result of the extensive hyperacetylation. These domains, which are nearly devoid of protamine, are postulated to represent an initial structural transition which is necessary for the proper histone removal and protamine replacement process to take place.

To the Editor.—Dr Ottinger's article (233:147, 1975) states that the size of an abdominal aortic aneurysm must be determined accurately, and with this I agree. However, I must disagree with his statement that this is almost always possible with "softtissue x-ray film views." Positive-contrast and ultrasound aortography offer much more information than plain films. In addition, these diagnostic modalities are helpful in determining involvement of renal and iliac arteries by the aneurysm or other arterial sclerotic disease, and they are certainly of interest preoperatively. There is no documented clinical mortality or morbidity caused by ultrasonography. The mortality and morbidity of positive-contrast aortography is quite low and certainly justified by the information gained. I am surprised that the author would not even mention these procedures in his article.

We have isolated cDNA clones encoding the high mobility group (HMG) protein HMG-1 in line CHO Chinese hamster cells. The cDNA clones correspond to the three HMG-1 mRNA species detected on Northern blots. Three different polyadenylation sites are found to be used. The three mRNA species of sizes 1.05, 1.45 and 2.45 kb are generated by differential polyadenylation at sites 115 nucleotides, 513 nucleotides and 1515 nucleotides downstream from the stop codon. A perfectly conserved putative poly(A) signal AAUAAA is present upstream of only one of the three poly(A) sites. Two homologous but imperfect sequences exist upstream from the other two poly(A) sites. All three HMG-1 mRNA species maintain significant levels throughout the M, Gl and S phases of the cell cycle and the rate of large HMG protein (HMG-1 and HMG-2) synthesis increases approximately two-fold from G1 to S phase.

FOR some time past1I have been endeavouring to decide whether the energy used in raising the water of the transpiration current is derived solely and directly from the inflow of heat at the evaporating surfaces of the leaf-cells, or whether stored energy (i.e. vital force) is in any way responsible for work done.

IF an observer views a piece of linoleum, or pavement, marked out as a checkerboard in light and dark squares, it is possible by causing the lines of vision of the two eyes to converge, that is, locating the fixation point, above the linoleum, to produce the impression that the pattern is raised above the level of the floor, and that it is on a smaller scale than that of the actual linoleum. This occurs when the images of two neighbouring dark squares fall on the corresponding points of the two retinas. A still smaller pattern at a still higher level may be produced when the images of two dark squares, separated actually by two light and one dark square, are caused by suitable convergence to fall on corresponding points of the two retinas.

MICROCHEMICAL tests on the assimilating cells of several plants indicate a considerable concentration of hexoses in the chloroplasts, or in the protoplasm immediately surrounding them. Other lines of experiment suggest that while sucrose is concentrated in the large vacuoles, invertase is held apart from it in the protoplasm.

IN a communication dated May 22, Prof. Ricca asks me to point out that there is an error in his letter as printed in NATURE of May 8, p. 655. There it is stated that the closing of the pinnules from base to apex of a pinna indicated times of transmission of the stimulating substance from the base to the apex of the pinna of 5, 4, 3½, 2½, 2 min. This of course should read, 5, 4, 3½, 2½, 2 sec.

L. W. SHARP in his “Introduction to Cytology” (1st ed. 1921 and 2nd ed. 1926) and C. D. Darlington in “Recent Advances in Cytology” (1932) wrongly attribute the origination of the term ‘strepsitene’ to me. As a matter of fact, I never used this term, but suggested in 1899 the now generally used ‘strepsinema’. I coined this word to describe the origin of the bivalent chromosomes of the heterotypic division first recorded by me in 1895 (“The Chromosomes of Lilium longiflorum”, Proc. R.I.A., 1895). The term ‘strepsinema’ is now often assigned to Grégoire owing, I believe, to an accidentally ambiguous expression of that writer, namely, “C'est le stade des noyaux diplotènes (Winiwarter, 00)—ou mieux noyaux strepsitènes ou strepsinema (Dixon, 00, Grégoire, 07), cette dernière expression rappelant les entrelacements caractéristiques de cette periode.” (“Les cinèses de maturation dans les deux règnes” (second memoire). La Cellule, 26, 2, p. 239; 1910.) Grégoire, so far as I can discover, uses the term ‘strepsinema’ here for the first time.

THE magnitude of the influence exercised by the stomata in the regulation of the water losses of plants appears to be very different under different conditions.

I HAVE just read W. Stempel's paper, “Ueber die Funktion der pulsierenden Vacuole,” to which Prof. Bayliss kindly directed my attention in NATURE of November 18, p. 376. Stempel's idea as to how the contractile vacuole works appears to differ fundamentally from my conception of its mechanism. He regards it as a preformed organ of the cell, developed to eliminate the waste products of metabolism, these products being introduced into the vacuole by the radiating canals which he endows with peristaltic action. He further postulates the existence of non-return valves between these radiating canals and the vacuole, and also of one at the point of exit of the fluid to the exterior. He considers that the evacuation of the contents is effected by the osmotic pressure in the vacuole, opening the valve and thrusting out the fluid, by the surface tension of the extruded drop, and by the pressure of the protoplasm. He does not indicate that the elasticity of the protoplasm or its tenacity enters into the mechanism. My suggestion may be summed up in the much simpler statement that the contractile vacuole is a necessary development in the protoplasmic semi-permeable gel wherever sufficient soluble material accumulates, the radiating canals being formed by the elastic recovery of the gel after rupture.

CONTRACTILE vacuoles are found only in those cells which lack a continuous cell-wall. This appeared to suggest that the function of the contractile vacuole is to eliminate dissolved crystalloids and so to keep down the osmotic pressure distending the semi-permeable protoplasm. Otherwise the latter, lacking the support which a continuous cell-wall gives, would continue to stretch and would finally rupture.

The term, contracture, is here used to designate a state of permanent shortening of a muscle which persists after section of the motor nerve or after death of the animal. Since under these conditions no nerve impulses can reach the muscle it is obvious that when once developed this sort of shortening is independent of the nervous system and is due to a more or less permanent alteration of the muscle. These contractures develop too quickly to be due to fibrosis and histological sections show no increase in connective tissue. The muscle fibers themselves have acquired a new and shorter length.When a resting muscle is made to support a moderate load it undergoes in addition to the elastic stretch, which disappears promptly when the load is removed, also a more or less permanent elongation (Nachdehnung of Blix,1permanent deformation of Langelaan2). In the contractures caused by tendon section and by tetanus toxin the elasticity remains approximately normal but the resistance to permanent elongation is greatly increased.In addition to its action on the spinal cord, tetanus toxin also exerts a direct action on muscle, causing a shortening and increased resistance to permanent elongation when injected after section of the motor nerve.This is a preliminary report.

IN 1858 Th. Hartig directed attention to the fact that many trees yield drops of sap when their bark is punctured in summer and autumn. This sap issuing from the inner layers of the bast was said to include small quantities of nitrogenous substances with large quantities of various kinds of sugar. Obviously its motion and constitution might yield some information on the transport problem of organic substances. We found the most abundant flow when the puncture reaches the inner layers of the bast; deepening the puncture so as to reach the wood, causes the sap exuded to be instantly drawn in by the tensile water in the vessels. Hence the exuded sap is not driven out by root-pressure through the outer xylem. The exuding sap is transmitted by the sieve-tubes as we demonstrated by forcing a solution of potassium ferrocyanide into the puncture and afterwards tracing its path by means of ferric chloride.

Recently in THE JOURNAL there appeared a report on gastroscopic observations of patients with infectious hepatitis.During the past two and one-half years we had occasion to employ gastroscopy in the course of diagnostic studies of some cases of chronic hepatitis because of gastric symptoms. For comparison, a number of cases of acute hepatitis were examined. A total of 43 cases of acute and chronic hepatitis were thus examined by gastroscopy. There were 23 cases of acute hepatitis and 20 of chronic hepatitis. In no case did gastric symptoms exist prior to the onset of hepatitis. X-ray examinations of stomach, duodenum and gallbladder were negative in all.ACUTE HEPATITISThe acute cases were diagnosed on the basis of characteristic clinical picture, enlarged and tender liver and jaundice. In the chronic cases there was obtained a history of previous attacks of acute hepatitis with persistent or recurrent symptoms of hepatitis, enlargement