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The accidental finding of intense fluorescence of the toenails and fingernails of persons receiving quinacrine hydrochloride (atabrine) was first noted in December 1945. This occurred when one of us (R. R. K.) was examining a patient with the Wood light and noticed a brilliant yellow-green fluorescence of the examiner's nails, as shown in the accompanying illustration. This examiner had just returned from the Southwest Pacific Theater, where he had been taking atabrine in daily doses for almost two years. The fluorescence of the so-called normal nail is much less intense than that of the "atabrine" nail and its color is quite different, in the normal nail being violet-blue and in the "atabrine" nail being yellow-green to almost white. Since then an additional 9 persons have shown this fluorescence. All of them had taken atabrine from five to twenty-one months. In no person not receiving atabrine has this fluorescence been observed.

The chief points presented in this paper are: 1. Following the ingestion of buckwheat (plant or seed) varicolored guinea pigs, white swine and goats exhibited symptoms of photosensitization, the degree of sensitization being in the order given. 2. Rabbits, dogs, white mice and rats did not manifest symptoms of photosensitization. 3. The symptoms and reactions were: agitation, itching, scratching of the ears, weakness, urticaria with sloughing and symptoms similar to those in anaphylaxis. 4. Microscopic examinations showed the lack of marked pathologic change. The lesions, such as petechial hemorrhage of the lungs, brain, liver, stomach and kidneys, suggest that profound toxemia has been present. 5. Lesions were not found which appeared to be suggestive of malignant neoplasms. 6. Irradiation by a quartz mercury vapor lamp apparently develops a resistance to photosensitization, probably because of increased pigmentation induced by ultra-violet light. 7. From the nature of the physiologic and pathologic reactions produced under various filters and from a consideration of the percentages of transmission of solar energy in the visible spectrum, it would seem that the region of photosensitization lies between 580 millimicrons (yellow) and the red end of the spectrum. This conclusion, moreover, is substantiated by the fact that irradiation by a quartz mercury vapor lamp (which radiates no energy in the visible spectrum at a wave-length greater than 579 millimicrons) produces no symptoms or reactions. 8. Spectrophotometric determinations of alcoholic extracts of grass (non-toxic) and of buckwheat (toxic) show the presence of two additional bands in the absorption spectrum of buckwheat with maxima at about 540 and 600 millimicrons, respectively, together with the common absorption zones at 430 to 490 millimicrons and 630 to 690 millimicrons. 9. Spectrophotometric determinations of blood serums of sensitized animals show, besides the usual absorption bands peculiar to oxyhemoglobin (with maxima at 540 and 580 millimicrons respectively), two zones with maxima at 600 and 660 millimicrons respectively. 10. The fluorescence of chlorophyll per se, as suggested by previous investigators, is not, in all probability, the cause of the sensitization induced by buckwheat. 11. Hematoporphyrine is not the photodynamic substance in all probability. 12. Phylloporphyrine may be the photodynamic substance. In this regard, also, the possibility of cholehematin is not to be ruled out.

Thomas Young as a scientist. Work on spherical aberration, chromatic aberration, oblique astigmatism and distortion. Modern progress along these lines, particularly as dependent upon wave length of light used. Differences between horizontal and vertical image focus. Primary and secondary astigmatic fields. Discovery of astigmatism by Young. Insufficiency of resolving power of eye. Illumination scale as a test and measure of astigmatism, both amount and axis. Accommodative mechanism. Work of Home and Ramsden. Aphakic eye accommodation. Young, Hering, and Ladd-Franklin theories of visual response. Work of Allen in support of Young's theory. Experiments of Burton and Browning. Duplicity theory. Co-ordination of retinal and cortical functions. "All or none" principle. Troland's work. Theories of vision, (a) chemical, (b) mechanical, (c) electrical. Edridge-Green theory. Houstoun's theory. Photo-ionic phenomena. Retinal current responses due to light stimulation. Quantum theory of vision.

The formula here discussed is the one that shows the change in effect of a lens produced by changing its position with reference to another lens or the eye. This is considered with reference to the distance of a correcting lens in front of the cornea, the amount of H. or M. corrected by a given lens, at a certain distance in front of the eye; and the effect of the thickness of the lens in altering spherical or cylindrical effect, when the lenses of the trial frame are to be replaced by the combination to be worn. The paper is contributed from the Section on Physics of the Mayo Clinic.

A decade ago there appeared the first of a series of publications by Blumgart and his associates1 concerning the use of injections of the disintegration products of radon (radium emanation) for the determination of the time elapsing between the introduction of the radioactive material at a given point in the blood-vascular system and its arrival at some other point in the system as detected by a shielded ionization chamber.In the early investigations the radioactive material was injected into the cubital vein of one arm and detection of its arrival in the radial artery of the other arm was accomplished by means of a modification of the cloud-chamber devised by Wilson.2 In the later studies Blumgart and his coworkers used ionization chambers of the type designed by Geiger3 and a mechanism for recording the time of passage of the active material between the chosen points. The ensemble of apparatus was somewhat cumbersome, unwieldy and expensive. A compact, portable and relatively inexpensive type of equipme...

A type of radiotherm developed in the Research Laboratories of the General Electric Company was used for the production of the high frequency fields. The oscillator delivered approximately 0.1 ampere per square inch of plate surface at a frequency of 27.3 million cycles (wavelength 11 meters). Cataphoretic measurements were made at level 0.211 D, where D is the total depth of the flat cataphoretic cell in the Mudd assembly of the Northrup-Kunitz apparatus. Measurements during a long series of experiments indicated a mean potential gradient (v/1) of 7.0 ± 0.4 volts per cm. for the field strength, or driving force, in the center of the cataphoretic cell. The mobility, u, is calculated from the relationship:in which tc is the “cataphoretic time,” that is, the time required by the streptococcus to move over a distance “d” under the influence of the electric field of the cell. Throughout these experiments the room temperature was 25°C., with a variation of ±2°C.The results of measurements of cataphoretic veloc...

ConclusionsThese experimental data show that, in living animals, the temperatures of certain different types of tissues are affected to different degrees by the systemic application of the shortwave electric field. Muscle tissine is affected slightly more than is subcutaneous tissue : intra-articular tissue is affected more than is muscle tissue. Furthermore, it has been shown that the reactions of anesthetized animals to general hyperthermia produced by this physical agent (short electric nave fields) are quantitatively different from those produced in unanesthetized animals. Measurements of temperatures of tissues of dead animals have shown that bone is heated much more markedly than is muscle tissue and they have indicated that the changes of temperature produced by this high frequency field are strictly dependent on the position and constitution of the various tissues.

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Potentiometric changes. — Various types of electrodes, to be described later, were used in the work to be reported. In general, however, electrodes of thin tinfoil were used and were attached to the leaves or stems of plants by means of acid-free kaolin ground in a mortar with a little water and glycerine after the method of Sen.1 In investigating potentiometric changes in leaves, both before and after irradiation, one electrode was fastened near the base of the leaf and the other one was placed at or near the tip of the leaf. Leads were then carried to a Leeds and Northrup potentiometer, using a high sensitivity galvanometer.Various spectral filters, such as Corning Glass Company filters of special make (G 554 FF, G 24, G 34 R, G 584, G 586 A, G 586 AW, G 392, G 984 B, G 985 B, G 986 A) and transmitting only infrared, red, blue and ultraviolet rays, and so forth, respectively, were employed.Infra-red (heat) energy, as such, could be removed from the sources of illumination (such as the quartz-mercury arc...

It is possible to produce changes in the cataphoretic distribution of streptococci by means of a high frequency electric field. Successive increments of exposure to high frequency energy produce cyclic or periodic changes in the cataphoretic distributions of the treated suspensions of streptococci. The changes produced in the cataphoretic distributions of streptococci exposed to a high frequency field are maintained in the subcultures of these organisms.

During the summers of 1926 and 1927 several sets of experiments were conducted in which eggs (from the same flock of white leghorns) were incubated under normal and under abnormal conditions. In all instances eggs were arranged in such a manner that some groups did not receive irradiation from a quartz-mercury are whereas other groups were irradiated for 10, 15 or 30 minutes a day, respectively. In general, these experiments showed that the daily average loss of weight for each egg when normally incubated amounted to 0.35 gm. Under abnormal incubation (with excessive moisture in the incubator) the loss of weight when the eggs were not irradiated was about 0.20 gm. With normal incubation, irradiation with ultraviolet light shortened the period of incubation 24 to 48 hours in about 20% of the eggs. The percentage hatch of normally incubated irradiated and nonirradiated eggs was practically the same. With abnormal incubation, ultraviolet irradiation increased the daily loss of weight and, with 30 minutes of ...