60 



case we have stated here, tliat even the absolute amount of dead 

 algae in the colourless sponges in darkness surpasses that in the 

 green ones in light. 



I will prove also by direct experiments, that of a same quan- 

 tity of green algae in sponge tissue — in other words, the concen- 

 tration of the green algae being the same — more algae die in 

 darkness than in light. Also here the factors of import, (export), 

 reduction and growth should be excluded as much as possible 

 in the experiments; that of multiplication can not be excluded, 

 but it will not be of influence on the results. For that purpose 

 we cultivate green sponges in flowing water from the conduit 

 for not too long a time. See Table 8, n». 100, 260, 261, 292, 

 293, 294, 333, 334, 343—344, (357, 359) — (348, 356, 358), 

 366 I, 366 II, 371, 372; all of them green Spongillae and 

 Ephydatiac. Generally of each sponge a piece was cultivated in 

 light and another piece under the same conditions in darkness. 

 In the beginning of the experiment both pieces of each pair 

 possessed an almost equal and large quantity of green algae, an 

 almost equal and small quantity of colourless ones with structure 

 and an almost equal and moderate quantity ot colourless ones 

 without structure. Now, during the experiments the number of 

 green algae generally proved to have more decreased and the 

 number of colourless algae with structure and that of colourless 

 ones without to have more increased in the sponge pieces in 

 darkness, than in the partner sponge pieces in light during the 

 same time. So it is clear, not onlij from the intensity of dying 

 (number of colourless algae with structure) hut also from the total 

 amount of dead algae (numher of colourless ones without structure), 

 that m sponge tissue, when the concentration of the green algae is 

 the same, much more algae die in darkness than in light (calcu- 

 lated per unit of time and of spoyige volume). (In some experi- 

 ments — n''. 344, 348, 358, 366 I, 366 II — the number of 

 colourless algae with structure has decreased at the end in the 

 sponge in darkness, or has remained the same. Evidently this 

 is caused by the already very much progressed decrease of the 

 green algae (by dying), for the number of the colourless ones 



