1940: Zoology

Observations on Animals.

Most Ancient of Living Animals.

Rabbits and opossums are probably the most ancient of the living known mammals on our continent states. They date back to times some 30,000,000 to 40,000,000 years ago.

Food Habits of Sea Otter.

O. J. Murie of the U.S. Biological Survey has made an extensive study of the food habits of the sea otter of the Pacific coast. It has been known that these otters eat sea urchins and almost no fish in contrast to their fresh water relatives, the river otter. These otters also feed on various mollusks. Mr. Murie has observed the otters while they are opening the hard-shelled mollusks. This is accomplished by hammering the shelled creature on a stone until the shell is cracked.

Cancerous Growth in Grouse.

Dr. Ian Cowan of the Provincial Museum, Victoria, B.C. reported a malignant or cancerous growth which was attacking the grouse in British Columbia. This tumor has been examined and diagnosed as a papillary cinomata. Dr. Cowan stated that this disease is present in epidemic proportions in localized areas which suggests the possibility of it being contagious. This growth is probably due to a virus which is transmitted by flies.

Salmon Migration.

Doctor E. B. Powers of the University of Tennessee has advanced a physico chemical theory as to the reason for salmon migration. Ecologists have heretofore suggested the 'homing instinct' as a reason for this migration. Now, Dr. Powers states that these fish swim up the specific streams having the lowest concentration of carbon dioxide. River waters which flow into the sea lower the concentration of carbon dioxide and the fish find the river mouths by going toward the regions of carbon dioxide concentration. However, one may still postulate another theory as to why this migration only occurs periodically.

Black Duck Dives for Food.

H. L. Kutz of Cornell University has demonstrated experimentally that the common black duck can dive for food on the bottom of water as much as ten feet deep. This is of interest since the black ducks have not been considered as divers but as preferring to gather their food ashore. However, when corn was dropped into water at depths of five, seven and ten feet, the black duck competed successfully for it with mallards at depths of 5 and 7 feet and monopolized it at the 10 foot level.

Experimental Studies.

Prenatal Environmental Influence.

Doctor A. M. Cloudman, while working on cancer experiments with mice at the Jackson Memorial Laboratory at Bar Harbor, Maine, brought to light the possibility that some of the effects now attributed to heredity may be due to prenatal environmental influence. In these experiments, unfertilized eggs were transplanted from one female mouse to another. These mice, when born, were considered 'pseudo-hybrids' in that they reacted to transplanted tumors in part as their foster mothers and in part as their real mothers.

Blood Type of Cats and of Man.

J. L. Rowland and G. McElory of Central College have shown in their experiments that cats have only one blood type instead of four as in man. Hence, among cats, any other cat can be the blood donor, with no fear of consequences. In their early transfusion experiments some signs of shock were noted but the addition of a small amount of glucose solution with the donated blood relieved this condition. These investigators also discovered the curious fact that, whereas cat blood serum would not cause agglutination of human corpuscles, human serum would produce the agglutination effect on corpuscles in the cat blood. It was also stated that the specific gravity of cat and human blood was almost the same.

Vitamin B Deficiency in Silver Fox.

Professor R. G. Green of the University of Minnesota and C. A. Evans of the U. S. Biological Survey state that silver fox breeders who feed their foxes a diet containing 10 per cent or more of fish are apt to have a serious nervous ailment develop in their animals. Basically, the disease is a vitamin B deficiency which is similar in reaction to a like disease in humans. However, the human disease is not caused by an over-feeding of fish food.

X-Ray Treatment in Carbon Monoxide Poisoning.

Dr. J. A. Cameron of the University of Missouri has found that monkeys which were exposed to concentrations of carbon monoxide that would have normally been fatal, recovered rapidly when treated with moderate amounts of X-rays. On the basis of these results, X-ray treatments may be of critical value in speeding recovery from carbon monoxide poisoning. Dr. Cameron also found that young rats and rabbits could withstand from six to ten times as great exposures to carbon monoxide as could adult animals of the same species. However, no such variation in age resistance was found in guinea pigs or monkeys.

Growth and Maintenance of Endocrine Organs in Tissue Culture.

Drs. Levenstein, Gordon and Charipper of New York University have adopted the methods of Carrel and Parker in their attempts to grow and maintain endocrine organs in tissue culture. They used the organs and sera of young and adult rats, guinea pigs and rabbits. The best results were obtained with organs from guinea pigs and rabbits, and the thyroid and pituitary glands were the easiest to maintain in culture. The ovarian and testicular maintenance was inconsistent, and negative results were obtained with all cortices of adrenal glands. These researches are being continued and will no doubt help in an analysis of the complex relationships of the glands of internal secretion.

Three-Weeks Human Embryo Specimen.

Prof. John S. Latta of the University of Nebraska has added another human embryo to the small collection already at hand in various institutions. This embryo was obtained from a uterus surgically removed from a hospital patient. It was found upon histological section of a part of the uterine endometrium. This embryo is estimated to be approximately three weeks of age and is of special value in the study of human embryology.

Blood Pictures of Football Players.

Dr. Farris of the Wistar Institute of Anatomy and Biology at Philadelphia has reported some interesting observations on the blood pictures of football players. Samples of blood were taken from a number of players before and after games throughout the season and a study of the red and white corpuscles was made. In general the following results were obtained: (1) Until mid-season, there was an average decrease of 822,000 cells per cubic millimeter following each game. (2) From mid-season on, there was an average increase of 618,000 red cells per cubic millimeter. It was also found that physical exertion and emotional stress produced changes in white cell numbers.

Longevity in Mammals.

Major S. S. Flower, a British zoologist, has for some years collected data on the length of life of a number of animals, and he finds that man is the longest-lived mammalian form. He has an authentic record of a human reaching the age of 114 years. Elephants, which were supposed to live longer than man were found to live about 50 years. The rhinoceros and hippopotamus reach the ages of 40 to 41 years in some cases. It was also stated that the size of an animal was in no way correlated with the age length, for the lion, tiger and the domestic cat show ages from 25, 19, and 20 years respectively. Ages of 500 years or more, claimed for tortoises and turtles, were stated as exaggerations. There were some records of tortoises reaching ages of 125 to 150 years and turtles up to 123 years. However, other reptilian species did not seem to be extraordinarily long-lived. See also BIOLOGY.