332 On Hypochlorin and its Production in the Plant. 



stances, we had to do only with an increase of the existing 

 quantity in the light. But this is not the case ; not merely 

 have we to do here with an increase of the existing quantity, 

 but hypochlorin, out of the whole series of materials which 

 can come under consideration here, and especially of those 

 which demonstrably occur together with it in the chlorophyll- 

 apparatus, is the only one which cannot without light form 

 itself in the seedling from the reserve-materials. Starch, 

 oil, cellulose, and sugar, as is well known, reciprocally pro- 

 ceed from one another in the exchange of materials in the 

 etiolated seedling, even without light. The green modifica- 

 tion of the chlorophyll-colouring-matter alone has, in most 

 Angiosperms, this property, in common with hypochlorin, of 

 being unable to originate without light from the reserve- 

 materials of the seedling ; and this agreement of the two 

 substances in such a decisive physiological point is certainly 

 a noteworthy indication of common relations to the processes 

 of assimilation, and of a direct interdependency. 



The striking analogy shown by chlorophyll and hypo- 

 chlorin in their relation to light in the Angiosperms extends 

 very remarkably to the exceptional conditions of chlorophyll- 

 formation in the Gymnosperms. As the Gymnosperms are 

 the only Phanerogams whose seedlings can, in some unex- 

 plained fashion, form chlorophyll- colouring-matter in the 

 dark, so also, singularly, the Gymnosperms are also the only 

 ones in whose seedlings hypochlorin makes its ajjpearance 

 even in darkness. 



I have paid particular attention to this peculiarity of the 

 seedlings of Gymnosperms, and tested it in a geat number 

 of comparative investigations on seedlings of Pinus picea, 

 montana, maritima, and Larix grown in the dark. 



Without going into a detailed description of the results and 

 of the relation of the quantity of hypochlorin present to the 

 age of the seedlings examined, I may here sum up the general 

 result of this series of investigations as follows : — In the 

 Conifers just mentioned hypochlorin occurs even in seedlings 

 grown in the dark ; and it may be indubitably ascertained 

 that the viridescence of these seedlings in the dark precedes 

 the presence of hypochlorin in them. 



It is true that frequently, especially in Pinus picea and 

 montana, there are scarcely any traces of hypochlorin in the 

 viridescent cotyledons even in seedlings several weeks old 

 (almost as late as the third week of germination) ; but, on the 

 other hand, other examples of the same species already show 

 noteworthy quantities of it; and if the little plants grow older 

 in the dark, say about four or five weeks, it may be easily 



