SECT. 2] 



AND WEIGHT 



379 



(/) Sheep. As early as 1847 Gurlt made a study of the increase in 

 length of the foetus of the sheep, but Colin is the only investigator 

 who has ever determined the 

 growth in weight (see Fig. 29). 

 Gurlt's figures, which are quite 

 regular, are given in Tables 10 

 and II of Appendix i. Faure- 

 Fremiet & Dragoiu, in the 

 course of their extended work 

 on the growth and chemical 

 development of the embryo- 

 nic lung in the sheep, made 

 measurements of the growth 

 of that organ, but did not give 

 any data on the weights of their foetuses as a whole, a very unfortunate 

 omission in view of the incompleteness of the literature on this 

 subject. 



[g) Pig. The only extensive figures in existence for the embryonic 

 growth of the pig are due to the careful work of Lowrey and of 

 Warwick. These are given in Tables 12 and 14 of Appendix i. 

 Lowrey's results will again be referred to in connection with the 

 growth of individual organs and parts in the embryo. LeBreton & 

 Schaeffer also measured and weighed a certain number of foetuses in 

 the course of their classical work on the behaviour of the chemical 

 nucleo-plasmatic ratio during 



60 100 



Days, Sheep (Colin) 

 Fig. 29. 



embryonic development. Their 

 figures are shown in Table 1 3 of i 

 Appendix i. \ 



(Ji) Cow. The embryonic \ 

 growth of the cow has been \ 

 investigated by several workers - 

 whose results are shown in ' 

 Table 15 of Appendix i. 



Fig. 30, constructed from 

 Franck and Hammond, should 

 be compared with Fig. 28 for the guinea-pig. 



{i) Man. The embryonic growth of man has been much studied, 

 and many thousands of embryos have been weighed. His's studies 

 have been the principal means of fixing the relation age/length, 



Months, Cow (Hammond). 

 Fig. 30. 



