iQii] Louis Hussakof and William H. Welker 217- 



numberof these tgg capsules were collected for this study. Another 

 siipply which we employed was taken directly from freshly caught 

 skates. The capsules were freed from their contents through a 

 longitudinal slit in each.^ 



The tgg capsules of the Port Jackson shark were sent us from 

 Japan in broken and dried condition.^ 



III. PREPARATION OF MATERIAL 



Egg capsules, especially such as are taken directly from the fish, 

 usually have flakes of dried ovo-protein adherent to their inner 

 sides. This material must be entirely removed, to insure an accu- 

 rate chemical study of the capsule. Our method of doing this was 

 practically the same with both kinds of capsules and was essentially 

 the following: 



The capsules were cut into small pieces and thoroughly washed 

 in running water. The pieces slowly sank to the bottom of the 

 vessel, allowing the lighter membranous films, which remained on 

 top, to be removed by simple decantation. Repeated washings also 

 served to dissolve and carry away some of the substance adherent 

 to the true capsular material. The washed pieces were then spread 

 out on sheets of white paper and all visible bits of adherent material 

 picked off by band. 



A preliminary test proved that peptic digestion, even when con- 

 tinued for 24 to 36 hours, does not visibly affect the capsular sub- 

 stance. The capsule pieces, after several additional washings in 

 water, were repeatedly subjected to long periods of peptic diges- 

 tion, until digestible protein had been entirely removed. They 

 were likewise subjected to pancreatic digestion, but in this case the 

 resultant change was inconsiderable : the digestive fluid became 

 slightly yellowish. The pieces were then washed successively in 

 water, alcohol, and ether, and finally dried over sulfuric acid. All 

 this preparatory treatment failed to affect the capsular substance 



' For these, as well as for a supply of sun-dried Raja capsules, picked from 

 the beach, we are indebted to Dr. Francis B. Sumner, Director of the U. S. Fish 

 Commission Laboratories at Woods Hole, Mass. 



^For this rare material our thanks are due to Professor Bashford Dean, of 

 Columbia University, who forwarded it to us from Japan, where he was at that 

 time (1905) carrying on biological investigations at the Misaki laboratory. 



