dicotyls themselves. Among various dicotyls, which have a Lower Cretaceous record and numerous present representatives, are not only the Magnoliaces and Trochodendraceæ, but Berberidaceae, Myricaceæ, Salicaceae, Fagaceæ, Moraceae (figs), Lauracea, Myrtacea (Eucalyptus). The list might be greatly extended. As a clue to the nature of the real early characters of dicotyls attention may be turned to the sassafras, poplars, elms, oaks and magnolias, all typical in the Comanchian. All these must show recognizable archaic characteristics in the seedlings; and in making comparisons with gymnosperms, Araucaria and the cycads afford just as critical data as the cycadeoids. G. R. WIELAND YALE UNIVERSITY SPECIAL ARTICLES THE REGULATION OF BLOOD VOLUME AFTER INFUSIONS OF SOLUTIONS OF VARIOUS SALTS. PRELIMINARY NOTE IN the recent work of Rous and Wilson1 it was demonstrated that the disastrous effects of hemorrhage are not the result of the withdrawal of hemoglobin from the circulation. They bled an animal until the hemoglobin was reduced from 80 per cent. to 20 per cent., i. e., three fourths of the original hemoglobin of the animal was removed without consequent serious effects. A reduction of four fifths, however, resulted in a somnolent, torpid condition, followed by death. Under the conditions of severe, sudden hemorrhage observed in man, the hemoglobin content is never reduced as much as these authors report. • Bayliss has shown that the factor which makes the results of sudden hemorrhage severe is the lowered blood pressure consequent to the reduction of volume of fluid in the circulatory system. Bayliss and Rous and Wilson state that saline infusion is almost useless in sustaining blood volume; and Bogert, Mendel and Underhill have shown in what a surprisingly 1 Rous and Wilson, Jour. American Medical Association, 70, 219. 2 Bayliss, Proc. Royal Society, 89, 380. 3 Bogert, Underhill and Mendel, Am. Jour. Physiology, 41, 189. short time infused saline solution leaves the circulation. Bayliss reports satisfactory results in sustaining blood volume when colloidal solutions of approximately the same viscosity as blood are used as infusion fluids. He used 6 per cent. gelatin or 7 per cent. acacia in Ringer's solution. Rous and Wilson have used the same solutions with the same satisfactory results. They also have used human plasma and horse serum. Human plasma has given them their best results. They dispute Bayliss's contention that the infusion fluid must have the same viscosity as blood. Hurwitz has used Locke solution containing 5 per cent. acacia for infusion in human patients and reports satisfactory results. In the course of some experiments of a somewhat different nature, the writer has had occasion to measure the rate of disappearance from the circulation of various isotonic solutions, each containing the same cation but a different anion. In view of the timeliness of this question of maintenance of blood volume, it seemed worth while to offer at this time what information was available which had a bearing on this problem. The solutions examined were isotonic with rabbit's blood. The bromide, nitrate, acetate, chloride, sulfate and thiocyanate of sodium were the salts used. These solutions were injected into the jugular vein of rabbits which had been anesthetized with ether. Blood samples were taken from the carotid and the dilution of the blood after injection was followed by the hemoglobin percentage, using the Haldane technic. Fifty cubic centimeters per kilo body weight, or the approximate blood volume, was injected in two minutes. The average time for the blood volume to return to normal after the injection was less than an hour for every salt used except one. This exception was the sulfate. When this salt was used the blood volume did not return completely to normal during the entire experiment. The amount of infused fluid which remained in the circulation was about 9 per cent. of the amount put in. 4 Hurwitz, Jour. American Medical Association, 68, 699. We can, then, confirm the results of Bayliss, Hurwitz and Rous and Wilson with chloride infusion; our experience supplements these in showing that, in so far as the bromide, nitrate and thiocyanate of sodium are concern erned, the use of them in infusions after severe hemorrhage would probably be of little permanent value in maintaining normal blood volume. Furthermore, it is probable that employment of sodium sulfate, even in combination with colloidal substances, will prove little more efficacious than Ringer's solution. ARTHUR H. SMITH YALE UNIVERSITY THE IOWA ACADEMY OF SCIENCE THE Iowa Academy of Science held its thirtysecond annual session at the Iowa State College at Ames, beginning at 1:30 P.M. on Friday, April 26. After the general program in the Assembly Room sectional meetings were held for the reading of papers of special interest and these were resumed on Saturday morning. The general business meeting was held on Saturday morning at 11 o'clock. Dean E. A. Birge, of the University of Wisconsin, gave the annual address at 8 P.M. Friday, on "The warming of an inland lake." The Iowa Section of the Mathematical Association of America and the Ames and Iowa Sections of the American Chemical Society held their meetings in connection with the sessions of the Academy. President Ross delivered his presidential address on "The history of the teaching of science" at the general meeting on Friday afternoon. At the business meeting on Saturday morning the following officers were chosen for the coming year: TITLES OF PAPERS Physics and Psychology cans. Temperature-time relations in canned foods during sterilization: GEORGE E. THOMPSON. Certain well-known mathematical formulæ are applied to heat penetration into foods packed in cylindrical It is found that if the diffusivity of the food be known the temperature-time curves may be constructed with a fair degree of accuracy for cans of any size and for any practical temperature range. A number of experimental and theoretical curves are shown for squash and corn. Some structural features of selenium deposited by condensation from the vapor state above the melting point. (b) The sublimation curve for selenium crystals of the hexagonal system: L. E. DODD. Stroboscopic velocities in the tonoscope: H. R. FOSSLER AND L. E. DODD. The eclipse expedition to Matheson, Colorado, June 8, 1918: D. W. MOREHOUSE. The X-ray spectrum of tungsten: O. B. OVERN. A new principle in the design of rheostats of large capacity: H. L. DODGE. On the coefficient of absorption of photoelectrons in silver and platinum: OTTO STUHLMANN, JR. On the production of opaque and the color of transparent and semitransparent metallic films: OTTO STUHLMANN, JR. Hall effects in thin silver films: G. R. WAIT. The effect of pressure upon the conductivity of selenium: E. O. DIETERICH. The measurement of basic capacities in motor ability: CARL E. SEASHORE. The speaker reported having devised and standardized a series of seven tests for the measurement of the basic forms of motor capacity. These are (1) motor ability, (2). timed action, (3) a simple response to a simple signal, (4) a simple response to a complex signal, (5) a complex response to a complex signal, (6) precision in action-direction, time, distance and force, and (7) strength and endurance. He also reported having devised simplified forms of instruments for these measurements. The time measurements are all made by means of small attachments, used on a phonograph. The complex reaction to a complex stimulus (chain reaction) is made by means of a carrier contact to a typewriter; and the strength and endurance test is made by means of a new form of ergograph, taxing the muscles of the forearm. Pharyngeal derivatives of Amblystoma: FRANCIS MARSH BALDWIN. This paper deals with the morphogenesis of the thyreoid and thymus glands, the postbranchial and epithelial bodies of Amblystoma, beginning with larvæ 5 mm. long, and including stages in metamorphosis and adult. The thyreoid gland arises as a solid outgrowth from the pharyngeal floor and breaks up into scattered cells, which, by mitotic division, give rise to the thyreoid follicles, in which colloid appears in late larvæ. There is no evidence of the formation of accessory thyreoids. The thymus gland arises from five pairs of anlagen, derived from the dorsal margins of the corresponding gill pouches. The anterior two degenerate, the other three form the definitive organ. There are no ectodermal contributions to the gland. The postbranchial body arises from a thickening of the pharyngeal floor, behind the last gill-pouch. In all cases, with one exception, it was asymmetrical. At the time of metamorphosis two pairs of epithelial bodies arise from the ventral parts of the last two gill pouches. They are the homologues of the parathyreoids of the mammals. Economic entomology and food conservation: R. L. WEBSTER. A list of the birds found in Marshall county, Iowa: IRA N. GABRIELSON. Notes on a wood borer: H. E. JAQUES. The influence of floods upon animals: D. M. BRUMFIEL. This paper is an analysis of the ways in which floods may affect animal life based upon observations made along Whitewater river in Fayette county, Indiana. Floods affect animal associations in two general ways, viz.: (1) by changing the habitats topographically, and (2) by changing the composition of the association without affecting the physical habitat. Topographical changes may be brought about as follows: (1) the course of the stream may be directly altered, (2) the local character of the stream may be altered, (3) changes may be brought about in the flood plain. Floods influence associations directly by: (1) destroying or removing forms already established and (2) providing a means of dispersal. The life and behavior of the house spider: H. E. EWING. Although the common house spider, Theridion tepidariorum K., is one of the most common arthropods observed about our houses no one in the past appears to have made a systematic and thorough study of its life and behavior. The complete life history is given, and observations extending over a period of several years are here reported. Scores of individuals were observed daily for many months both in captivity and in their natural environment. The cocooning process is described and illustrated by figures. Notes on courtship, cannibalism, food habits, emotions, instincts and intelligence are given. A preliminary list of the Acarina of Iowa: ALBERT HARTZELL. But few lists of Acarina have been made in this country. In 1886, Professor Osborn and Professor Underwood published a preliminary list of the Acarina of North America. This list included 99 species and 28 genera. In the Iowa list here given 75 species and 55 genera are included. The mite fauna of Iowa is in general very similar to that of Illinois, yet it is interesting to note that in the vicinity of Ames we find several of the northern forms. No records of sheep scab or human scabs have been noted in recent years. Sheep scab at one time occurred in this state, but due to the efficient work of the United States Bureau of Animal Industry it apparently has been eradicated. Notes on the food of the yellow perch in Cayuga Lake: W. A. HOFFMAN. This paper consists of preliminary work relating to the food of the yellow perch, Perca flavescens Mitchill, which was done in the limnological laboratory of the department of entomology at Cornell University. Twenty-one fish were seined on two days, June 25 and July 14. An examination of the stomach contents of these perch was then made. Crustacea, fish and fish eggs were found in the greatest numbers and volume. Of the Crustacea, Decapods represented by Cambarus were present in eight stomachs, while Amphipods which consisted mostly of Gammarus and Hyalella were in ten. Chironomids, Trichoptera and Odonata made up most of the insect food. Only two Ephemerida were found, whereas these insects often are the only food to be found in the perch. The remainder consisted of Gastropoda, Hydrachnida and Entomostraca. The cranial nerves of the dogfish: SALLY P. HUGHES. Spiders of the family Attide collected in the vicinity of Ames: I. L. RESSLER. SCIENCE FRIDAY, JULY 12, 1918 THE MAN OF SCIENCE AND THE AN APPRECIATION OF SPENCER FULLERTON NEVER are the limitations of language If I could create, in however small de- But how impossible it is to give adequate Such a man has a thousand sides, each most fa- But Professor Baird was not many-sided 1 Address delivered at the dedication of a me- |
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