55 



without any mutual regularity ; while the process of division 

 proceeds but very slowly (pag. 31). 



2. The weaker the concentration of the algae present in a 

 culture or in a sponge tissue in light, the higher is their 

 intensity of multiplication (Table 9, 10; in sponges one should 

 consider the concentration at the beginning and at the end of the 

 experiment; the abnormal nos 3361, 341, 3651, 375, 376 should 

 be neglected) ; in darkness, on the contrary, the intensity is al- 

 ways the same (viz. + 0) in sponges (Table 10, conf. Table 6). 

 I will not examine, now, the cause of these phenomena; one 

 may ascribe them to the quantity of food (eg. CO^), the algae 

 can dispose of. All this concerns the intensity calculated per 100 

 green algae. Now we have to remould these results and to cal- 

 culate them per unit of sponge volume. We therefore should 

 know the mutual proportions of the various concentrations, which 

 we can only calculate roughly (p. 13). In, this way we find in 

 light (Table 10 and 8, n°. 3371, 347, 3381; 3331, 3341, 343) on 

 the one hand an intensity (per 100 algae) of 13 with an average 

 quantity of algae (in the unit of volume) of VII, on the other 

 hand an intensity (per 100 algae) of 1 with an average quan- 

 tity of algae (in the unit of vol.) of XI. Now I stated that 

 XI = + 70 X VII. Consequently, the same sponge volume in light, 

 containing 100 algae in the weak concentration and therefore 

 possessing an intensity of multiplication of 13, must contain 

 in the strong concentration 7000 algae and an intensity of 

 multiplication of 70. Thus : in light the infensittj of multiplication 

 of the algae in sponge tissue, calculated per unit of sponge volume, 

 in a strong concentration of the algae surpasses the intensity in a 

 weak concentration; in darkness they are the same, viz. 0. 



3. The intensity of multiplication of the algae in the sponge 

 tissues as well as of those in cultures is much larger in light 

 than in darkness; in a sponge in darkness it is ±0 (Table 10, 

 cf. Table 4 and 6). The concentration of the algae in every 

 two experiments belonging together (one in light, the other in 

 darkness) was generally almost the same in the cultures; in the 

 sponge tissues, however, in light (necessarily) even stronger than 



