Conditions of its Production in the Plant. 331 



plant together with the latter. This becomes still more 

 distinct, and the connexion of assimilation with the formation 

 of hypochlorin is rendered still clearer, when the above-de- 

 scribed experiments on seedlings are slightly varied. 



The viridescence of plants takes place, according to present 

 notions, under a less intensity of light than assimilation. In 

 half-obscurity, i. e. in strongly darkened places, therefore, 

 seedlings become perfectly green, without, however, being 

 able to keep themselves alive. They perish, not much later 

 than when they vegetate in complete darkness. Although I 

 regard the assumption that assimilation is entirely suppressed 

 under small intensities of light as an error, the process is 

 undoubtedly prejudiced ; and therefore the accumulation of 

 products rich in carbon, which the seedling requires after 

 the consumption of its reserve-materials, is impossible under 

 light of small intensity. 



I have accordingly repeated the experiments on the pro- 

 duction of hypochlorin with seedlings which I reared, not in 

 the dark, but from the time of their germination in half- 

 obscurity. In these, even in such as had lived from eight to 

 fourteen days in half-obscurity, I likewise found no trace of 

 hypochlorin, although the cotyledons, plumules, and primor- 

 dial leaves of these little plants were well developed, and, 

 especially, although these organs were as deeply and perfectly 

 greened in the half-obscurity as is the case in seedlings 

 which have been able to develop themselves quite freely and in 

 full light for several days. 



As a matter of course the result depends upon the light 

 under which the plants grow ; for even under moderate day- 

 light in the place of experiment hypochlorin is present in the 

 viridescent seedlings, and its quantity visibly increases with 

 the increase of the light. 



It is nevertheless not difficult to rear beautifully green 

 seedlings without any trace of hypochlorin. This may be 

 done, for example, by growing the plants in the experimental 

 room at a great distance from the window and under bell- 

 glasses covered with grey paper. 



The just-demonstrated dependence of the formation of hypo- 

 chlorin upon the influence of light would not per se prove a 

 direct close relation to assimilation, but only indicate (as in 

 the case of starch, fat, cellulose, and sugar) that it belongs to 

 the series of those materials the storing up of which, as nearer 

 or more remote products of assimilation, must necessarily be 

 dependent upon the accumulation of carbon in the plant 

 caused by light. This would certainly be the case if, in the 

 instance of hypochlorin, as with the above-mentioned sub- 



