161 



water from the conduit. Proof that defecation must take place 

 even on a large scale. For with a microscopic observation the 

 brown particles, which orginally were in a great number all over 

 the tissue, proved then to have almost disappeared. The same 

 counts for colourless sponges which have captured such a great 

 number of carmine grains from a suspension, that they have be- 

 come quite red ; here too the carmine is removed in pure water, 

 so that the sponges become colourless again; while one finds the 

 ejected carmine conglomerates at the bottom of the culture- vessel. 



Next I will mention that, just as I discovered the pheno- 

 menon of the capturing of coarse (food-) particles by (cells of) 

 the canal-walls for the first time in ravel preparations of sponge 

 tissue (p. 148 — 152), I obtained the first indications of the way 

 in which defecation takes place by means of the same pre- 

 parations : 



As I mentioned on p. 149, one finds in a sponge (Spongilla 

 or Ephydatia), which has been in a carmine suspension for some 

 hours, a great number of carmine grains l^t in the choanocytes 

 and 2^^ in amoeboid cells (without symbiotic algae but often 

 with all sorts of detritus), while on the contrary carmine is not 

 or rarely to be found in the amoebocytes with symbiotic algae. 

 Has the sponge been in pure water for some time after it got 

 out of the suspension, one finds, as was partly mentioned on 

 p. 146 — 148, only little carmine in the choanocytes, but now 

 much (as conglomerates, upto 4 ^ci large) in the amoebocytes with 

 symbiotic algae, while it is also to be found rather much, and then 

 in big conglomerates (upto 14 pc), in amoeboid cells (present in 

 a small number) without symbiotic algae but with (often) all 

 sorts of detritus. The sponge itself then appears to be less red 

 than it was immediately after it came out of the carmine, while 

 now on the contrary the water, in which it has been, is coloured 

 slightly red. If the sponge remains in pure water for some days 

 more, one does not only find but little carmine in the choano- 

 cytes but also in the amoebocytes with symbiotic algae. The 

 carmine, however, is still present in a great quantity and in 

 large conglomerates in the often mentioned amoeboid cells with- 



