SYNTHESIS OF PROTEIDS 



117 



aeration of the water is desirable (page 49). They should be stood in a 

 good light, but not direct sunlight, but it is well to keep them darkened and 

 under a bell jar until the seeds germinate. 



If, after this experiment, the student has any doubt as to 

 the ability. of plants to synthesize proteids from the photosyn- 

 thate and nitrogen-containing salts, he may convince himself 

 by an experiment detailed by 

 Detmer (58), and which he will 

 himself try later in connection with 

 Fermentation. 



Turning next to the proteid 

 formed, analogy with photosyn- 

 thesis would imply that some one 

 simple form is first made from 

 which the others are derived. 

 The student must seek to learn, 

 through the literature, whether 

 there is a basal proteid, what 

 intermediate stages are known or 

 supposed to exist in its forma- 

 tion, where it originates in the 

 plant, and what its energy relations 

 are, whether chemosynthetic or 

 photosynthetic. And he should FlG ' ^--Water-culture vessel; 

 express his results in a proper It is a tumbler> with D top of hard paraffin 



exposition of OUr knowledge Of and wrapped in felt paper. 



these important matters. Here also he should consider whether 

 there is any known excretion of nitrogen-holding compounds, 

 as occurs so abundantly in animals. 



It is to-day a matter of common knowledge that there is one 

 family of plants, the Leguminosce, which have unique relations 

 with aerial nitrogen through the colonization on their roots of 

 nitrogen-fixing bacteria. The student should now inform him- 

 self, through the literature, upon our present knowledge of this 

 subject, and upon the efforts being made to turn it to practical 

 account. And he will be aided much in an understanding of 



