474 Miss H. Chick. On a Unicellular Green Alga, [Feb. 28 



Table VII (b).— Culture in Solution " A," to which a small amount of 

 Glucose had been added (about 0*25 per cent.). Started August 5, 

 1902. 











Culture of Chlorella 

 pyrenoidosa. 



No. of 

 analysis. 



Date 

 of 



analysis. 



— 



Control. 



Whole 

 culture. 



• 



Clear 

 liquid after 



centri- 

 fugalisation. 









Per cent, 

 nitrogen. 



Per cent, 

 nitrogen. 



Per cent, 

 nitrogen. 



j 1 



5.8.1902 



Free ammonia 

 Albuminoid 



ammonia 

 Nitrites and. 



nitrates 

 Total nitrogen 



-00254 

 -00015 (?) 



o -oo 



-00269 





— 



! i - 



23.10.1902 



Tree ammonia 

 Albuminoid 



ammonia 

 Nitrites and 



nitrates 

 Total nitrogen 



-00231 

 -00022 



o-oo 



0-00253 



0-00070 

 -00141 



o-oo 



-00211 





3 



20.10.1902 



Free ammonia 

 Albuminoid 



ammonia 

 Nitrites and 



nitrates 

 Total nitrogen 



-00210 

 -00034 



o-oo 



0-00244 



-00074 

 -00166 



o-oo 



-00240 



-00063 

 -00081 



o-oo 



0-00144 



General Conclusions. 



It appears to be generally true that most plants containing chloro- 

 phyll prefer the nitrogen of their food in the form of nitrates. On the 

 other hand, many observers have shown that certain plants can 

 assimilate nitrogen in the form of ammonia, and in fact prefer it. Of 

 these latter experiments, many were not performed with the precautions 

 necessary to prevent the access of bacteria {e.g., nitrifying organisms), 

 and hence must be considered inconclusive. Some, on the contrary, 

 were most carefully carried out with every precaution, and among 

 these may be mentioned those of Kriiger,* who showed that his Chlo- 

 rella protothecoicles and Chlorothecium saccliaropkilum (two algae nearly 

 allied to Chlorella pyrenoidosa) could both assimilate their nitrogen 



* Zopf's ' Beitrage z. Pnys. u. Morph. Med. Org.,' Leipzig, 1894, vol. 4, p. 115. 



