Study of Sjrirogyra nitidcL, 221 



source, and that it probably plays an important role in the 

 synthesis of the plant proteid. 



Chemical Changes in the Conjugating Cells. 



Having obtained some insight into the chemical charac- 

 ter of the vegetating cell, it was considered advisable to 

 investigate the changes in composition, if such changes 

 take place, in the conjugating cell. Loew, in the paper 

 before cited, states that during conjugation a decrease in 

 the starch content takes place, with a corresponding rise in 

 the sugar content. This observation was confirmed during 

 the present investigation — not only does the glucose and 

 starch vary considerably, but the entire cell seems to be 

 fundamentally altered. 



It was found impracticable to conduct the analysis ot 

 this material as was done in the case of the vegetating, 

 since the conjugating threads were inextricably mixed 

 with those not conjugating, and even in the individual 

 threads, conjugating cells were more frequently separated 

 by several vegetating cells. The work, therefore, was 

 accomplished by the aid of micro-chemical reactions, and 

 comparisons were made with the normal material. Obser- 

 vations were started when the tubes had just begun to push 

 out, and were continued until the entire act had been com- 

 pleted. The conjugating material was first noticed in the 

 pond in the latter part of April, 1896, after a week of very 

 warm weather had stimulated vegetation. 



In the very early stages it was found that the chlorophyll 

 bands, alike in their matrix and ground substance, had 

 very materially altered. If the cells be treated with carbon 

 disulphide or chloroform, a disintegration of the band 

 results, because of the solvent action of the reagent upon 

 the green substance. The reagent first destroys the char- 

 acteristic contour and arrangement of the pyrenoid centre 

 and starch grains, and collects the green chlorophyll in 

 large drops at the edges of the bands. Ultimately, if the 

 action of the solvent be continued, the green solution is 



