(57) Barnett, S. A.: Competition among wild rats. Na- 
ture 175: 126 (1955). 
(52) Marx, M. H.: The effects of cumulative learning 
upon retroactive inhibition and transfer. Comp. 
Psychol. Monograph 18, No. 2 (1944). 
(5J) Rosvold, H. E.: The effects of electroconvulsive 
shocks on gestation and maternal behavior. J. 
Comparative and Physiological Psychology 42: 
118-136; 207-219 (1949). 
(54) Rosvold, H. E., and Walker, A. M.: Effect of 
electroconvulsive shocks on nest building in the 
male albino rat. Proc. Society for Experimental 
Biology and Medicine 72: 270—272 (1949). 
(55) Mirsky, A. F., and Rosvold, H. E.: The effect of 
electroconvulsive shock on food intake and hunger 
drive in the rat. J. Comparative and Physiological 
Psychology 46: 153-157 (1953). 
(56) Mirsky, A. F., Looney, E., and Rosvold, H. E: 
Maze retention deficit following electroconvulsive 
shock independent of feeding schedule. J. Com- 
parative and Physiological Psychology 47: 403-405 
(1954). 
(57) Rosvold, H. E., Kaplan, S. J., and Stevenson, J. A.: 
Effect of electroconvulsive shock on adrenal cortex 
of the rat. Proc. Society for Experimental Biology 
and Medicine 80: 60-62 (1952). 
(58) Rosvold, H .E., and Royce, J. R.: Electroshock and 
the rat adrenal cortex. Arch. Neurology and 
Psychiatry 70: 1-12 (1953). 
(59) Seitz, P. F. : Effects of litter size during infancy 
upon adult behavior in the rat. Amer. J. Psychiatry 
110: 916-927 (1954). 
(60) Leslie, P. H., Venables, U. M., and Venables, 
L. S. V.: The fertility and population structure of 
the brown rat (Rattus norvegicus) in corn-ricks and 
some other habitats. Proc. Zoological Society of 
London 122: 187-238 (1952). 
(67) King, H. D.: The growth and variability in the body 
weight of the Norway rat (Mus norvegicus). Anat. 
Record 25: 79-94 (1923). 
(62) King, H. D.: Birth weight in the gray Norway rat 
and the factors that influence it. Anat. Record 63: 
335-354 (1935). 
(63) King, H. D.: Life processes in gray Norway rats 
during fourteen years in captivity. Amer. Anat. 
Memoirs No. 17, 77 pp. (1939). 
(64) King, H. D.: Life processes of the gray Norway rat 
during ten generations in captivity. Amer. Anat. 
Memoirs No. 14: 11-70 (1929). 
(65) Wiesner, B. P., and Sheard, N. M.: The duration 
of life in an albino rat population. Proc. Royal 
Society Edinburgh 55: 1-22 (1935). 
(66) Davis, D. E., and Emlen, J. T.: The placental scar 
as a measure of fertility in rats. J. Wildlife Manage- 
ment 12: 162-166 (1948). 
(67) Morlan, H. B., Utterback, B. C., and Dent, J. E.: 
Domestic rats in relation to murine typhus control. 
Public Health Monographs of the U.S. Public 
Health Service 5: 1-20 (1952). 
(68) Davis, D. E., and Hall, O.: The seasonal reproduc- 
tive condition of female Norway (Brown) rats in 
Baltimore, Maryland. Physiological Zoology 24: 
9-20 (1951). 
(69) Wiesner, B. P., and Sheard, N. M.: Maternal be- 
havior in the rat. London, Oliver & Boyd, 1933. 
(70) Willier, B. H.: Ontogeny of endocrine correlation. 
In W. B. Saunders (Ed.), Analysis of Development, 
Philadelphia, Pa., Chapter X, 1955, 574-619. 
(77) Gaunt, R., Howell, C., Antonchak, N., and 
Glitzer, M.: Adrenal cortical steroids and body 
growth. Anat. Record 111: 560 (1951). 
(72) Becks, H., Simpson, M. E., Li, C. H., and Evans, 
H. M.: Effects of adrenocorticotropic hormone 
(ACTH) on the osseous system in normal rats. 
Endocrinology 34: 305-310 (1944). 
(73) Holzbauer, M., Rigler, R., and Rosenkranz, W.: 
Lethal retardation of growth by electric shock. 
Nature 169: 190-191 (1952). 
(74) Vogt, Marthe: The effect of emotion and /3-Tetra- 
hydronapthylamine on the adrenal cortex of the 
rat. J. Physiology 114: 465-470 (1951). 
(75) Weininger, O.: Physiological damage under emo- 
tional stress as a function of early experience. 
Science 119: 285-286 (1954). 
(76) Bullough, W. S.: Stress and epidermal mitotic activ- 
ity. I. The effect of adrenal hormones. J. Endo- 
crinology 8: 265-274 (1952). 
(77) Christian, J. J.: Effect of population size on the 
weights of the reproductive organs of white mice. 
Amer. J. Physiology 181: 477-480 (1955). 
(78) Christian, J. J.: Effects of population size on the 
adrenal glands and reproductive organs of male 
mice in populations of fixed size. Amer. J. Physi- 
ology 182: 292-300 (1955). 
(79) Clarke, J. R.: The effect of fighting on the adrenals, 
thymus and spleen of the vole (Microtus agrestis). 
J. Endocrinology 9: 114-126 (1953). 
(80) Clarke, J. R.: The general adaptation syndrome in 
the study of animal populations. Brit. J. for the 
Philosophy of Science 3: 350-352 (1953). 
(81) Blumenthal, H. T.: The nature of cycle variations 
in mitotic activity. Growth 14: 231-249 (1950). 
(82) Christian, J. J.: The adreno-pituitary system and 
population cycles in mammals. J. Mammalogy 
31: 247-259 (1950). 
(83) Green, R. G., and Larsen, C. L.: A description of 
shock disease in the snowshoe hare. Amer. J. Hy- 
giene 28: 190-212 (1938). 
(84) Woods, J. W.: Differences in adrenal responses to 
adverse conditions in wild and domesticated Norway 
rats. Federation Proceedings 12: 159 (1953). 
(85) Evans, H. M., Simpson, M. E., and Choh, H. L.: 
The gigantism produced in normal rats by injection 
of the pituitary growth hormone. I. Body growth 
and organ changes. Growth 12: 15-32 (1948). 
(86) Simpson, M. E., Asling, C. W., and Evans, H. M.: 
Some endocrine influences on skeletal growth and 
differentiation. Yale J. Biology and Medicine 23: 
1-27 (1950). 
(87) Young, F. C.: The experimental approach to the 
problem of diabetes mellitus. Brit. Medical J. 
Nov. 17: 1167 (1951). 
287 
