Chap. XVII. ABSORPTION BY THE QUADRIFIDS. 415 



the quadrifids were affected after 21 hrs. as if a solution of car- 

 bonate of ammonia had been used ; for the i^rimordial utricle 

 was thickened in specks, which seemed to graduate into separate 

 granules. Three bisected bladders were also irrigated with a 

 fresh solution of urea of the same strength; their quadrifids 

 after 21 hrs, were much less affected than in the former case ; 

 nevertheless, the primordial utricle in some of the arms was 

 a little shrunk, and in others was divided into two almost 

 symmetrical sacks. 



Three bisected bladders, after being examined, were irrigated 

 with a putrid and very offensive infusion of raw meat. After 

 23 hrs. the quadrifids and bifids in all three specimens abounded 

 with minute, hyaline, spherical masses; and some of their 

 primordial utricles were a little shrunk. Three bisected blad- 

 ders were also irrigated with a fresh infusion of raw meat ; and 

 to my surprise the quadrifids in one of them appeared, after 

 23 hrs., finely granular, with their primordial utricles somewhat 

 shrunk and marked with thickened yellowish specks; so that 

 they had been acted on in the same manner as by the putrid 

 infusion or by the salts of ammonia. In the second bladder 

 some of the quadrifids were similarly acted on, though to a 

 very slight degree; whilst the third bladder was not at all 

 affected. 



From these experiments it is clear that the qiiad- 

 rifid and bifid processes have the power of absorbing 

 carbonate and nitrate of ammonia, and matter of 

 some kind from a putrid infusion of meat. Salts of 

 ammonia were selected for trial, as they are known 

 to be rapidly generated by the decay of animal 

 matter in the presence of air and water, and would 

 therefore be generated within the bladders contain- 

 ing captured prey. The effect produced on the pro- 

 cesses by these salts and by a putrid infusion of raw 

 meat differs from that produced by the decay of the 

 naturally captured animals only in the aggregated 

 masses of protoplasm being in the latter case of larger 

 size ; but it is probable that the fine granules and 

 small hyaline spheres produced by the solutions would 

 coalesce into larger masses, with time enough allowed. 



