42 



Arbacia's which had been brought into the laboratory on the 

 same morning. The Thyone's I used, however, were in the 

 aquarium already for a week. 



The corpuscle samples and those which had been freed from 

 corpuscles, were added with liberal quantities of cane-sugar 

 and starch. Some toluene was added to each of them ; after that 

 they were placed into the incubator at 40° and kept there for 

 some days. In case either an amylolytic enzyme or an invertase 

 were present in the liquid, one might in that way expect a 

 reduction of Fehling's solution. 



After two days a Fehling's test was made on an aliquot 

 of all the samples. All were negative at first sight, on standing 

 however a precipitate was seen which was much heavier in the 

 corpuscle samples in both cases. 



Two days later a complete reduction was seen in the corpuscle 

 sample of Thyone. In the others the reduction was incomplete 

 and the precipitate only became visible on standing. In the 

 urchin this precipitate was at least five times as heavy — estimating 

 this roughly from the quantity of precipitate — in the corpuscle 

 sample as in the otherone. On the next day the difference was still 

 more striking, now at least ten times as much was present in 

 the corpuscle sample. 



This experiment shows clearly that the corpuscles must explain 

 the remarkable observation of Cohnheim. Since this author 

 does not mention whether or not he filtered his samples, this 

 seems to be very well possible. 



15. ROLE OF THE CORPUSCLES. 



Several assumptions have been made with regard to the func- 

 tions of the amibocytes of the Echinoderms. Some of these do 

 not have any direct bearing on the problems studied in the 

 present paper. Some authors have described special calcigenous 

 cells, carrying reserve-calcium for the formation of sceletal ele- 

 ments. Others have emphasised their function as phagocytes. 

 The original experiments of Metschnikoff 84") on phago- 

 cytosis which gave rise to his very illuminating conceptions of 

 this process were conducted on this very group. As a matter 

 of fact they seem to play a very important role in the meta- 

 morphosis of this group. Secondly he could show that foreign 

 bodies, bacteria, dying mesodermal cells, etc. can be swallowed 

 by these corpuscles. Mammalian corpuscles injected into these 

 animals were surrounded by a kind of Plasmodium of amibocytes 

 and digested; I myself could observe something of the same 

 nature in Stichopus after bone-black injection (see chapter 23). The 

 role which the corpuscles play in excretion will be discussed in 

 in chapter 23; that they may carry waste has been proved 

 by Durham 34) and 35) and Saint Hilaire 112). 



