56 



in darkness. Consequently, if this concentration had been equal, 

 the intensity of multiplication (calc. p. 100 alg.) in the sponge 

 in light would have surpassed that in darkness even more. The 

 cause of this phenomenon is, of course, again the state of feeding 

 of the algae. 



This rule concerns the intensity calculated per 1 00 green algae ; 

 while the concentration of the algae was then supposed to be 

 the same in light as in darkness. From this follows: the concen- 

 tratioti of the algae being the same, tlteir intensity of multiplication 

 in sponge tissue in light, calculated per unit of sponge volume, 

 largely surpasses the intensity in darkness. 



F. The factor of mortality. 



In chapter VI we have stated that all colourless algae present 

 in sponge tissues are dead or dying green ones; and in chapter 

 YIl^, that generally rather a considerable quantity of the green 

 algae is continually dying in those tissues, first changing into 

 colourless algae with structure and then into colourless ones without 

 structure (p. 45). As besides we see from Table 5 (n°. 68 p, for instance), 

 that there the stage of colourless alga with structure is passed 

 much more quickly than that of colourless one without structure, 

 we might in general consider through analogy also in the sponge 

 tissue the number of colourless algae with structure to be a direct 

 measure for the intensity of dying of the green algae during a 

 short period preceding our analysis ; and the number of colourless 

 algae without structure, on the contrary, to be the total amount 

 of the algae, that died (in the same sponge volume) during a much 

 longer period preceding our analysis. This conclusion agrees with 

 the results from the analyses of Table 6 ; for there we have stated 

 (pag. 48, 10) that the number of the colourless algae without 

 structure is always much larger than that of the colourless ones 

 with structure. This is only possible, if the first mentioned stage 

 of colourless ones (that without structure) is passed less quickly 

 than the second. 



Knowing this, we may conclude from the analyses of Table 6 

 (pag. 46 — 47, 2, 3) that in green sponges in light as well as in colour- 



