338 



THE UNFERTILISED EGG AS A 



[PT. Ill 



on this point is of an unsatisfactory histological nature, and any 

 discussion of it must inevitably include an unprofitable proportion 

 of guesswork. Thus, Jorgensen differentiated histologically between 

 two substances which seemed to be present in the unripe egg of 

 Patella vulgata, ergastoplasm No. i and ergastoplasm No. 2, one at 

 least of which was responsible for the formation of the vitelline 

 globules. Faure-Fremiet & Garrault identified ergastoplasm No. i 

 with the mitochondria, and ergastoplasm No. 2 with the fatty con- 

 stituents of the yolk. But if two forms of vitellin existed, one in loose 

 combination with a nuclein and the other free, the staining reactions 

 of histological elements mainly constituted by one or other of these 



Table 37. 



substances would very likely differ, and it is possible that an explana- 

 tion on these lines may in the future correlate the chemistry with the 

 histology of the yolk. The vitellin question has been in a measure 

 reviewed by McCrudden, whose table (given in Table 37) illustrates 

 the difficulty of summing up the findings of investigators at all 

 succinctly. 



The amino-acid analyses (Table 34) are rather more interesting. 

 We have data for the vitellins of the herring, the trout, the cod, 

 and the sturgeon among fishes, the frog among amphibia, the grass- 

 snake among reptiles, and Hemifusus tuba, a gastropod. To this may 

 be added amino-acid analyses of the mixed egg-proteins of the sea- 

 urchin egg and the eggs of the brook-trout and the giant salamander, 

 as well as the albumens of cod and sturgeon and the mucoprotein 

 of Hemifusus. If the fish ichthulin analyses of Iguchi or Hugounenq 

 be compared with those of Table 1 1 for the vitellin of the hen, no 

 very marked differences can be observed, although the predominancy 



