158 



already before (p. 97), both these methods of digesting are pro- 

 bably not different in principle, but only in quantity of secerned 

 enzyme (in other words, in rapidity). 



I made no investigations into the enzymes acting (p. 96), 

 except that the presence of a lipase was made probable (p. 89, 

 98—99). Perhaps I will have the opportunity later on to extend 

 my investigation in this direction. 



As for the carmine captured by the sponge, I can mention 

 that, after it had got into the amoebocytes with symbiotic algae, 

 it was generally soon ejected by these again and removed out of 

 the sponge body afterwards — about which in the next chapter. 

 Only very seldom I have been able to observe a beginning of 

 digestion, a solution of the carmine; but then also, very remark- 

 able indeed, a solution was to be distinguished within a vacuole 

 (this became entirely light-red) from a solution quite free in the 

 protoplasm of an amoebocyte, in which case from the carmine 

 grain as centre the red colour slowly spread through the plasma. 

 In fact a nice illustration of what I have so often mentioned for 

 the symbiotic algae as plasma and vacuole digestion. A proof 

 now, that indeed the difference is a matter of rapidity (of digest- 

 ion), is given in these observations of carmine-solution in the 

 fact, that carmine grains were never to be found any more in a 

 light-red vacuole, on the contrary there were, when the solution 

 took place free in the protoplasm. 



I obtained no data concerning a possible digestion of food else- 

 where, eg. in the „intercellular" spaces of the parenchyma. 



This about the digestion of food. It had already been acknow- 

 ledged in literature [see among others Biedermann (6) and also 

 CoTTE (13)] that especially the amoebocytes took part in it. 



E. THE DEFECATION AND EXCRETION IN THE 



FRESH-WATER SPONGES. 



■» 



Also these phenomena I have observed in my living prepara- 

 tions of sponge tissue. 



On the whole, there is but little known for certain in litera- 



