348 President's Address. 



pliyll colouring matter, is formed in gymnosperms without the action 

 of light. Colourless embryos of Pinus picea, montana, raaritiina, 

 Larix, have no trace of ]iyj)ochlorin. Sachs showed tliat from the 

 seeds of such plants germinating in darkness, the embryos, though 

 kept quite dark, become green. This is quite unexplained. In the 

 first stages of germination, when the seedling is already gi-een, no 

 hypochlorin is formed ; but iu later stages, though still in darkness, 

 it appears in the tissues. Thus, hypochlorin appears in gymno- 

 sperms grown in darkness, and, as is the case in angiosperms after 

 the chlorophyll colouring matter, in most cases appearing in four 

 to five weeks' old seedlings, which have become green long before. 

 'There is no doubt, however, that light favours hypochlorin formation. 



This condition in gymnosperms does not disallow the hypothesis 

 that hypochlorin is formed in assimilation. Although formed in 

 the embryo without access of light, yet in adult gymnosperms as in 

 angiosperms it is the result of light-action. It resembles chlorophyll 

 in this respect. Because chlorophyll occurs in embryos of gymno- 

 sperms grown in the dark, one does not suppose that light has no 

 influence in its production in other plants, and the like must be 

 held regarding hypochlorin. Possibly in seedling gymnosperms the 

 hypochlorin may arise by metastasis without direct assimilation. A 

 substance — perhaps a volatile oil — may descend from the mother- 

 plant into the seeds, and out of it the hypochlorin in the seedling 

 may be formed. Whatever be the first assimilation product, it is 

 possible that it may be regenerated by metastasis from its own 

 products, and for all proximate constituents of the plant the same 

 process of regeneration is possible. But in respect of its origin, 

 hypochlorin appears more strongly bound up with assimilation than 

 these other proximate constituents of the plant body ; for, of all 

 the products in the chlorophyll apparatus, hypochlorin is the only 

 one besides the chlorophyll colouring matter itself, which, in angio- 

 sperms, cannot develop without light. 



Complete anatomical proof that hypochlorin is the primary 

 assimilation product is not yet possible, our knowledge of it is too 

 recent, and it is only by artificial imitation of the assimilation 

 process that all doubt can be set at rest. Yet the close relation of 

 hypochlorin with the function of the chlorophyll-corpuscle — with 

 its assimilation and respiration — has been fully and with certainty 

 established through the foregoing account of its origin, its constant 

 occurrence in chlorophyll-corpuscles, and its behaviour in light and 

 oxygen. With no body in the cell does the hypochlorin exhibit 

 such close relationships of function as with chlorophyll colouring 

 matter. So much so, indeed, as to almost lead to the belief that it 

 is an artificial product of the chlorophyll colouring matter developed 



