54 



E. The factor of multiplication. 



We stated above (p. 27, 31, 47, and Table 4, 6) that the 

 green symbiotic algae multiply, when isolated in cultures, as well 

 as within the tissues of the sponge. 



We have to examine now the rapidity of the multiplication 

 under diiferent outer conditions (Table 9, 10). We will do this 

 by counting the number of the stages of division present in 100 

 green algae at a certain moment. Before we proceed to this in- 

 vestigation we should ask, what factors rule this number. It will 

 increase by 2 factors: 1. by the number of the algae (per 100) 

 which divide within a certain space of time, 2. by the time in 

 which the division of an alga is accomplished. We may say 

 that the l^t factor depends on the state of feeding of the algae, 

 the 2n^ on the temperature. The latter was always the same in 

 my experiments of one series; therefore we may consider the 

 time, in which the divisions of the algae took place, to be equal 

 also for every experiment of a same series. Consequently, we 

 possess in the number of stages of division per 100 algae (the 

 percent of stages of division), which I examined in my in- 

 vestigations, a direct measure, true for every series of experi- 

 ments, of the number of algae (per 100) which divide within a 

 certain, equally long space of time ; in other words, a measure of 

 the intensity of multiplication of these algae. 



In this way we will have examined this intensity always cal- 

 culated per 100 green algae, which are present in a culture or 

 in a tussue of a sponge. The other factors (import, export, re- 

 duction, growth and dying), however, have been studied or will 

 be studied per unit of time and per unit of volume of sponge 

 tissue. Consequently, we have to bring also our results con- 

 cerning the intensity of multiplication in accordance with these 

 units, in order to combine all results afterwards. 

 Proceeding now to my investigations we see: 

 1. Periodicity does not occur in the intensity of multiplication^ 

 neither for the algae in the sponge tissue, nor in cultures ; nei- 

 ther within 24 hours, nor within some days (Table 9). I there- 

 fore believe that the algae continually multiply each in its turn, 



