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ascidians, but the presence of vanadium in association with the proteid escaped Griffith's observation. Whether non-metallic respiratory pigments represent degeneration, or whether they are phylogenetic predecessors of metallic pigments, is difficult to decide; but their presence in the animal kingdom shows that the function of oxygenation is not dependent upon the presence of a metal in the pigment molecule a fact which gives strong indication that the association with metals was occasioned by the need of a greater capacity for ready oxidation and reduction, the need, that is, of a catalyst.

HARVARD UNIVERSITY

JOHN F. FULton, Jr.

THE INFLUENCE OF HEAT AND OXIDATION UPON THE NUTRITIVE AND ANTISCORBUTIC PROPERTIES OF COW'S MILK1

In a recent paper2 from the Minnesota Experiment Station we submitted data which indicated that the nutritive and antiscorbutic properties of cow's milk are dependent upon the nature of the feeding materials which constitute the dairy ration.

In April, 1920, a series of studies was initiated with the view of ascertaining the influence of heat upon the nutritive properties and the antiscorbutic potency of milk. The experimental milk used in these studies was obtained from an Ayershire cow fed upon a ration composed of the same types of feeding materials throughout the experimental period. By this method it was hoped that we might eliminate fluctuations in the vitamine content of the dairy ration and thereby reduce to a minimum any variations in the nutritive properties of the milk.

In these studies we have used a total of 163 guinea pigs, and control groups were included in each series. In the first series of experiments it was found that boiled milk was

1 Published with the approval of the director as Paper No. 247, of the Journal Series of the Minnesota Agricultural Experiment Station.

2 Dutcher, R. A., Eckles, C. H., Dahle, C. D., Mead, S. W., and Schaefer, O. G., J. Biol. Chem., XLV., 119-132, December, 1920.

practically equal, in nutritive properties, to the unheated raw milk. The pasteurized milk, heated at 145° F. for 30 minutes, produced scurvy very quickly and all of the animals died in a very short time. Examination revealed the fact that the pasteurized milks had been stirred rather violentiy with motor-driven propellors, while the boiled milk had not been stirred mechanically. This led us to believe that oxidation had occurred in the pasteurized milks due to the intimate contact of air with the milk particles. Consequently, many new animals have been added with the result that we have been able to show that the nutritive and antiscorbutic properties of cow's milk are destroyed by oxidation. Some destruction occurs when air is bubbled through milk at 145° F. for 30 minutes, but the destruction is much more marked when oxygen or hydrogen peroxide is used. Oxygen and hydrogen peroxide will destroy the antiscorbutic accessory at room temperature although the destructive action is hastened as the temperature increases. Milk may be pasteurized in closed vessels or boiled in the open air without appearing to lose its nutritive and antiscorbutic properties when fed to guinea pigs. When carbon dioxide is bubbled through the milk, it compares very favorably in nutritive properties with the raw milk.

Our work, now in progress, on orange juice shows that the antiscorbutic properties are not destroyed by boiling for 30 minutes. At least, if destruction occurs it is not discernible with the methods employed. Hydrogen peroxide destroys the antiscorbutic factor in orange juice at room temperature, and the speed of the oxidation is hastened as the temperature increases. Oxidation would appear to be a more important factor than heating as far as the nutritive and antiscorbutic properties of milk are concerned.

EDLA V. ANDERSON,
R. ADAMS DUTCHER,

C. H. ECKLES,
J. W. WILBUR

MINNESOTA EXPERIMENT STATION, UNIVERSITY FARM, ST. PAUL

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Candidates for admission must be graduates of approved colleges or scientific schools with at least two year's instruction, including laboratory work, in Chemistry, and one year each in physics and biology, together with evidence of a reading knowledge of French and German.

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The charge for tuition is $250 per annum, payable in three instalments. There are no extra fees except for rental of microscope, certain expensive supplies, and laboratory breakage.

The annual announcement and application blanks may be obtained by addressing the

Dean of the Johns Hopkins Medica School Washington and Monument Sts. BALTIMORE, M.D

SUMMER WORK FOR GRADUATES
IN MEDICINE

Beginning Tuesday, June 6th, and ending Thursday, July 16th, a course in medical diagnosis, including laboratory exercises in clinical pathology and demonstrations in pathological anatomy, will be offered. The course will be limited to twenty students, fee $100. Applications should be made to the Dean's Office.

Louisiana

SCHOOL OF MEDICINE

(Established in 1834)

ADMISSION: All students entering the Freshman Class will be required to present credits for two years of college work, which must include Chemistry (General and Organic), Physics and Biology, with their laboratories, and at least one year in English and one year in a modern foreign language.

COMBINED COURSES: Premedical course of two years is offered in the College of Arts and Sciences, which provides for systematic work leading to the B.S. degree at the end of the second year in the medical course.

School of Pharmacy, School of Dentistry and Graduate School of Medicine also.

Women admitted to all Schools of the College of Medicine

For bulletins and all other information, address Tulane College of Medicine

P. O. Box 770

New Orleans, La.

Northwestern University

Medical School

Situated in Chicago in close proximity to important Hospitals with an abundance of clinical material.

Admission Requirements-Two years of College credit including a satisfactory course in Physics, Chemistry, Biology or Zoology, and French or German. Course of Study-leading to the degree of Doctor of Medicine-Four years in the Medical School and a fifth year either as Interne in an approved hospital or devoted to research in some branch of Medical Science.

Graduate Instruction-in courses leading to the degree of Master of Arts or Doctor of Philosophy. Research Foundation-The James A. Patten Endowment for Research affords unusual opportunities for advanced students of Medical Science to pursue special investigations.

Research Fellowships-Four fellowships of the value of $500 each are awarded annually to promote scholarly research.

Tuition Fees-The tuition fee for undergraduate stu dents is $180.00 a year.

For information address

C. W. PATTERSON, Registrar

8421 South Dearborn Street Chicago, Illinois

Marine Biological Laboratory Woods Hole, Mass.

INVESTIGATION Entire Year

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une 29 to August 9 1921

SUPPLY DEPARTMENT Open the Entire Year

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Animals and plants, preserved, living, and in embryonic stages. Preserved material of all types of animals and of Algae, Fungi, Liverworts and Mosses furnished for classwork, or for the museum. Living material furnished in season as ordered. Microscopic slides in Zoology, Botany, Histology, Bacteriology. Price lists of Zoological and Botanical material and Microscopic Slides sent on application. State which is desired. For price lists and all information regarding material, address

GEO. M. GRAY, Curator, Woods Hole, Mass.

The annual announcement will be sent on application to The Director, Marine Biological Laboratory, Woods Hole, Mass.

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