18 



light they also photosynthesise (produce carbohydrate or oil). This 

 having been established, we are justified in declaring — in 

 connection witli the points of similitude already known — that 

 the green colouring matter of the sponges is clilorophyll. I have 

 been able to procure both proofs. 



1. In order to prove the production of 0.^ in light, I proceeded 

 in the folio wing way : 



a. I cut tv^o equal pieces from a branch of a green "Spongilla, 

 and an equally large pieee from a colourless one. These 

 pieces were put separately — without having been taken out of 

 the water — into glass vcssels, filled with water from the con- 

 duit, uiider inverted funnels and tubes, etc. (see Table Ic). One 

 green piece and the colourless one were placed into bright day- 

 (evt. sun-)lig]it, the other green piece, however, on the same spot 

 in darkness. At first no gasbubbles were to be found anywhere 

 in the vessels ; but at the end of the experiment the green sponge 

 piece, exposed to light, showed numerous rather large bubbles, 

 as well at the outside as within its tissue, and the funnel con- 

 tained a lot of them. The green sponge in darkness and the 

 colourless one in light, on the contrary, didn't show any; except 

 a few bubbles inside and outside their funnels, evidently formed 

 by air from the water. I have repeated this experiment several 

 times, al way s with the same result (Table la, b) : only the green 

 sponge, when exposed to light, formed gas-bubbles, the green 

 sponge in darkness did not, nor did the colourless one in light. 

 The quantity of gas produced, however, was always too little for 

 a determination. Yet it is almost beyond doubt, that it has been O2 '). 



b. WiLSON (70) and Muller (4()) stated the fact, that rubbed 

 sponge material can regenerate to new sponge globules, able to 

 develop themselves almost in the same way as the gemmulae of 

 the frosh-water sponges. Now, I put equal quantities of such 

 globules originating in one green Spongilla, into 12 little glass 

 vessels of the same capacity, filled with water and covered with 



1) According to Brandt, Hoog stated already in 1840 the rising; of gasbubbles 

 from a Spongilla exposed to sunlight. 



