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



A stock solution was made having the following composition : — 



Glucose 1-0 per cent., K 2 HP0 4 0-2 per cent., MgS0 4 0-04 per cent., 

 CaClo # 02 per cent., distilled water 100 c.c. 



With this stock solution eight different culture solutions were pre- 

 pared containing respectively 0*1 per cent, of the following: — 



Of these solutions, the cultures grown in those containing urea and 

 uric acid were found to nourish exceedingly well, and by far the best, 

 while of the others, the culture in the liquid containing xanthin gave 

 evidence also of being very well nourished. 



Uric Acid Culture. — An analysis was made of this culture in the 

 ordinary way. In the case of the control liquid, it was found that 

 no free ammonia was obtained, and comparatively very little of the 

 nitrogen of the uric acid was yielded as albuminoid ammonia. It was 

 found, however, that when Chlorella pyrenoidosa had been growing in 

 the liquid, the yield of albuminoid ammonia was much increased, 

 showing that much of the nitrogen of the uric acid had been assimi- 

 lated by the organism and converted into albuminoid ammonia. 



Urea Culture. — In the case of the control urea-containing liquid* 

 about 25 per cent, of its nitrogen was yielded, on analysis, as free 

 ammonia. In the case of the inoculated fluid, about 30 per cent, of 

 this ammonia was found to have disappeared, that is, to have been 

 assimilated. After addition of alkaline permanganate, distinctly more 

 ammonia was yielded from the liquid in which alga had grown than 

 from the sterile control. 



It is difficult to draw very positive quantitative conclusions from the 

 results of the above two experiments, but it seems evident at least 

 that this alga is able to assimilate with very great ease and without 

 any previous decomposition the nitrogen both of urea and uric acid. 

 The former substance has also been found by other observers* to be 

 a useful source of nitrogen for plants in certain instances. 



In the case of Chlorella pjrenoidosa, however, these facts are of 

 special interest, when it is remembered that the plant naturally grows 

 in water that has been contaminated by sewage. 



Caineron, 'Trans. Brit, Assoc.,' 1857; Ville, ' Compt. Bend.,' vol. E5, p. 32. 



1. Asparagine. 



2. Aspartic acid, 



3. Urea. 



4. Uric acid. 



5. Peptone. 



6. Xanthin. 



7. Hippuric acid. 



8. Stock solution, without further 



addition. 



