The formation of protfids in plant-cells. 



55 



grow in solutions containing as sole organic matter sulfonal 



(0,2%). 



Of course sulfuretted hydrogen is only produced in the neces- 

 sary amount for immediate need, as accumulation would be 

 noxious ; experiments intented to prove that H 2 S as such can be 

 assimilated, meet for obvious reasons with some difficulties. 



Our considerations, therefore, lead logically to the conclu- 

 sion, that the atomic groups, serving for the formation of proteins 

 are three very reactive combinations : 



Form-aldehyde, ammonia and sulfuretted hydrogen. 



II. The Formation of Proteids in 

 Chlorophyll-bearing Plants. 



As chlorophyll-bearing plants produce by assimilation car- 

 bohydrates, it is natural that such well suited compounds 

 should form here also the main source of carbon for the synthe- 

 sis of proteids. 1 ^ Nitrates or ammonium salts furnish the nitro- 

 gen, sulfates the sulfur. The chemical behaviour of the protein 

 compounds indicates very clearly, that neither the nitrogen 

 nor the sulfur is connected with oxygen, but only with carbon 

 and hydrogen. It follows, therefore, that reduction of the 

 nitrates and sulfates has to take place, here as well as in the 

 case with the lower fungi. If all conditions are otherwise 

 favorable, then the synthetical work proceeds so rapidly that 

 the intermediate steps cannot be directly traced. From numer- 

 ous observations, however, the conclusion appears justified 

 that it is asparagin to which an important role must be attributed 

 in this connection, a conclusion which at first was arrived by 

 the ingenious Th. Hartig. Borodin, Pfeffcr and Kellner declared 

 asparagin to be the form, in which the transportation of albu- 

 minous bodies takes place. The most important investigations, 

 however, we owe to E. Schulze and his school. 



Asparagin has been found normally in many plants, but under 

 special conditions in still more cases. The root of Althcva contains 



i) It can hardly be doubled, that all such substances as are capable of being 

 converted into starch, as glycerine (Arthur Meyer, Laurent) or glycol or methyl alcohol 

 (Th. Iiokomy) also serve as sources of carbon for the formation of protein compounds 

 Also the combination of formic aldehyde with primary sodium sulfite may be used 

 under certain circumstances (Th Bokorny). 



