There is sufficient evidence to indicate that man grows for a longer period of time than chimpanzee who in turn has a greater duration of growth than rhesus monkey. The problem of this paper was to determine if there was a concomitant decrease in a rate of growth. Using the relative growth rate of Fisher ('21), it appears that for most of their period of growth, the rate of change is the same. Immediately after birth, when we have no data for children, rhesus monkey grows significantly faster than chimpanzee. By a year and a half their rates are the same, and neither species shows a sex difference. From seven years (age of youngest children) until children start through puberty, there is no sex difference in Homo sapiens, and the human rate does not differ from the chimpanzee rate. Because of the resemblance between the primate curve for rate and that for dairy cattle, it is postulated that this curve is more mammalian than primate and that during phylogeny the primates have merely increased the duration of time when growth is possible. Man does show one new feature, the puberal growth spurt, which is not found in the non-human data considered.The implications of these conclusions for primate phylogeny and for growth are discussed.
An attempt to survey spontaneous teratogeny among nonhuman primates bred under laboratory conditions revealed interesting but nonconclusive results. Data on controlled breeding in 2950 animals representing 12 species yielded an estimated incidence of 0.44% malformations. No indication was found that other primates display more malformations than man, and the limited information available suggests that there may be fewer spontaneous defects in nonhuman forms.Macaques and baboons appear to respond in a similar manner and to the same types of extrinsic agents as does man. Thalidomide, Rubella virus and androgenic hormones produce similar defects in comparable dosage at equivalent stages in development in both groups. Several other agents thought not to be teratogenic in man have been realistically tested in primates and also found ta be non-teratogenic.Using thalidomide an attempt was made to determine the degree of sensitivity and delimit the susceptible period of Macaca mulatta to this drug. Typical limb malformations were obtained with a single dose of as little as 16 mg/kg between the twenty-fifth and thirtieth days of gestation. Comparable doses at earlier and later ages were without effect, thus d e m g the susceptible period. In addition, evidence of a positive dose-response relation and of a cephalocaudal gradient in teratogenesis was obtained.
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