194 



stances green and colourless chlorophyll corpuscles pass into each 

 other (pag. 37— M) — for we will try to explain in this way, why 

 green sponges occur in light and colourless ones in darkness, and why 

 green sponges grow colourless in darkness and colourless ones grow 

 green in light (pag. 35) — ; and as we can see from Table 8, that 

 in general a green sponge must be in darkness for at least a month 

 in order to grow almost colourless — during wliich period its number 

 of green corpuscles strongly decreases, that of the colourless ones 

 strongly increases — and that a colourless sponge must be in light 

 for at least a month in order to grow somewhat green — during 

 which period its number of green corpuscles strongly increases and 

 that of the colourless ones increases a little — ; we should observe 

 our cultures of the corpuscles for more than a month. 



From the tables 4 A — I) results (see also p. 37 — 44): 

 i. The isolated green chlorophyll corpuscles, when cultivated in light 

 or darkness in all kinds of feeding media, remain normal (green 

 for instance) and alive for months, and multiply by normally 

 green descendants. 



2. The green corpuscles multiply more rapidly in light tlian in dark- 

 ness (pag. 55). 



3. In general the number of isolated colourless chlorophyll corpuscles 

 in the cultures does not increase, but even decreases under all cir- 

 cumstances mentioned sub i; the corpuscles disappear from the 

 culture and never pass into the green form. 



4. When the green corpuscles decrease in number, the colourless ones 

 increase; so the first ones probably pass into the latter (while these 

 disappear after some time). 



5. Bacteria do not seem to harm the green corpuscles; but mould, 

 diatoms and algae make them grow colourless (n" 84!) (which 

 colourless corpuscles disappear). 



