80 INANITION AND MALNUTRITION 



periods of war or famine (Ploss; Ruge '16), but convincing statistical evidence is 

 lacking. Richter ('17), Loenne ('18) and Linke ('19) found no evident change 

 in sex ratio during the world war. 



Among domestic animals, Girou de Buzaieingues (1828) found that the per- 

 centage of male lambs from 150 abundantly nourished ewes was about 40; 

 while in 150 poorly fed ewes the percentage of male lambs was increased to 60. 



Girou's conclusion was supported by the experiments of Duesing ('85) and 

 by Wilckens ('86), the latter presenting statistical data from about 30,000 

 domestic mammals (including 16,000 colts, 4,900 calves, 6,750 lambs and 2,300 

 pigs). Wilckens concluded that good nutrition in utero tends to produce 

 relatively more females; malnutrition, more males. Slonaker and Card ('23), 

 however, found an increased ratio of females in albino rats on a restricted 

 vegetable diet. 



Among amphibians, the earlier experiments of Born ('81, '94) upon Rana 

 fusca indicated that relatively more females are obtained from larvae placed on a 

 nourishing diet; and Yung ('83, '85) in Rana esculenta apparently produced 

 more females on richly protein diets. Cuenot ('99), however, obtained negative 

 results with Rana temporaria. King ('07), in careful and extensive experiments 

 upon larvae of the toad (Bufo lentiginosus) , likewise failed to find any significant 

 differences in sex ratio on various diets (meat, wheat, mixed, and egg-yolk) ; 

 but her underfeeding experiments failed on account of the high mortality. 

 The problem of sex determination in amphibians is greatly complicated by 

 the difficulty in distinguishing the sexes during the early larval stages, and the 

 question is still unsettled. 



In reviewing the evidence, Geddes and Thomson ('01) concluded that in 

 vertebrates, as well as invertebrates, sex may be determined by various external 

 factors, especially nutrition. Mitchell ('n), on the other hand, concluded 

 that "In nearly every case, however, other observers have obtained conflicting 

 results, or placed another interpretation on similar results, whilst in none of 

 the cases has the factor of selective mortality been sufficiently excluded." 

 In the recent biological literature, the views concerning sex determination 

 have been dominated largely by the "accessory chromosome" theory, according 

 to which the sex is supposed to be determined by the relative amount of nuclear 

 chromatin present in the gametes at the time of fertilization. It may be pointed 

 out, however, that even under these conditions the sex ratio might still be 

 affected by previous malnutrition of the gonads in the parent organism during 

 the process of oogenesis and spermatogenesis. Further investigation is there- 

 fore necessary before this important question can be settled. 



Postnatal Loss in Birth Weight. — The normal postnatal decrease in human 

 body weight was discovered by Chaussier about a century ago, according to 

 Benestad ('14). A similar decrease in newborn puppies, kittens and rabbits 

 was denied by Kehrer ('70) but was found in the guinea pig by Minot ('91) 

 and by Bessesen and Carlson ('23). According to Ostwald ('08), such a loss 

 is very general in animals. Although chiefly due to other factors (loss of 

 meconium, urine, etc.), it is generally admitted that a part of this postnatal 

 decrease in body weight is due to inanition, on account either of insufficient 



