14 EEYTHEA. 



starch is not glucose, but maltose. But Mr. Horace Brown 

 has shown in his remarkable experiments on feeding barley 

 embryos, that, while they can readily convert maltose into 

 cane-sugar, they altogether fail to do this with glucose. We 

 may conclude, therefore, that glucose is, from the point of 

 view of vegetable nutrition, a somewhat inert body. On the 

 other hand, evidence is apparently wanting that maltose 

 plays the part in vegetable metabolism that might be 

 expected of it. Its conversion into glucose may be perhaps 

 accounted for by the constant presence in plant tissues of 

 vegetable acids. But, so far, the change would seem to be 

 possibly disadvantageous. Perhaps, glucose, in the botanical 

 sense, will prove to have a not very exact chemical con- 

 notation. 



" That the connection between cane-sugar and starch is 

 intimate, is a conclusion to which both the chemical and the 

 botanical evidence seems to point. And on botanical 

 grounds this would seem to be equally true of its con- 

 nection with cellulose. 



" It must be confessed that the conclusion that ' cane- 

 sugar ' is the first sugar to be synthesised bj^ the assimila- 

 tory processes seems hard to reconcile with its probable 

 high chemical complexity, and with the fact that, botanically, 

 it seems to stand at the end and not at the beginning of the 

 series of metabolic change." 



Protoplasmic Chemistry. 



The synthesis of proteids is the problem which is second 

 only in importance to that of carbohydrates. Loew's views 

 of this deserve attentive study. Asparagin, as has long 

 been suspected, plays an important part. It has, he says, 

 two sources in the plant. ' It may either be formed directly 

 from glucose, ammonia (or nitrates) and sulphates, or it 

 may be a transitory product between protein-decomposition 

 and reconstruction from the fragments. '^^ 



In the remarks I made to the Chemical Society I ventured 

 to express my conviction that the chemical processes which 



38i,oc. cil., 6i. 



