35 

 The thesis of Tschernow " (122) is a natural continuation 



of the investigations of Majewski, which dealt with herbivorous 

 animals, while Tschernow performed the study of the chemical 

 composition of foetal fluids on carnivorous animals, mainly 

 cats (he investigated forty-four foeti, weighing from 0,074 to 

 107,3 gm) . In addition, in his collection there were embryos 

 of four dogs, nine swine, and one human, and also one horse 

 embryo, which was used for comparison with carnivorous animals. 

 Tschernow established that in the amniotic fluid the relation 

 of the quantity of water to the solid constituents remains 

 constant. In the allantois, the quantity of fluid in the 

 process of foetal development gradually decreases, and simul- 

 taneously the relative quantity of water diminishes (from 989.5 

 to 949.8%), The amount of solid material in the fluid of the 

 allantois increased at the expense of the organic matter 

 (albumin— from 1.05 to 5.59%; sugar— from 0.95 to 2.02%; urea— 

 from 1.48 to 12.10%). The albumin of allantoic fluid, accord- 

 ing to Tschernow, is not necessarily secreted by the capillary 

 renal vessels, although this possibility is not excluded, as 

 the vessels of the foetus probably possess different permeabil- 

 ity properties than the born animals, in whose urine there are 

 no traces of albumin. Tschernow thought that albumin passes 

 in the fluid of the allantois from the amniotic fluid, where 

 it is always present. The sugar in the allantoic fluid of 

 carnivores is significantly lower than in herbivores (in sheep, 

 according to Majewski, it averages 7.57%, and in horses, 

 according to Tschernow 's observations, it averages 11%), On 

 the other hand, the urea in the allantoic fluid in carnivores 

 is greater than in herbivorous animals. 



The tradition of embryological investigations in Dorpat 

 University, which is connected with the influence of Baer, 

 remained. Thus, M. Braun, who was present from 1880 to 1886, 

 in the beginning as a prosector of comparative anatomy and 

 then as professor of zoology, worked on the embryology of 

 bivalves, tapeworms, reptiles, birds, and mammals (among these 

 works, investigations on the development of the wavy parrot 



35. Nikolaus Tschernow (Estonus) , DE LTQUORUM EMBRYONALIUM 

 IN ANIMALIBUS CARNIVORIS CONSTITUTION CHEMXCA 

 (Dorpat, 1858) , 35 pp. 



485 



