and Laboratory Methods. 2309 



teaching at the idea is shown by the fact that we recur to it time and again in 

 zoology and also in botany. 



I believe the relation of oxidation to the process of excretion is not made 

 clear by most text-books. That should be done. Moreover, it is essential that 

 the pupil should understand not only that nephridia, kidneys, and skin are excre- 

 tory organs, but that tracheae, gills, and lungs are, also. When we come to the 

 Protozoa, we find a good opportunity to make a point of the fact that all the 

 processes of nutrition may be carried on in one cell. I may say in passing that 

 we use the compound microscope in the study of Protozoa. That is the only 

 time the class as a whole uses it in zoology. Very little is said about physiol- 

 ogy while our time is occupied with the starfish and the hydroids. 



During the five weeks study of the frog, the pupils come into a fair 

 understanding of the anatomy of their own bodies, by comparison, and of the 

 physiological processes going on there. The frog is the only form that the 

 pupils dissect. They do it with considerable satisfaction and profit. Our 

 course as it has been planned in the past requires us to lay in a stock of frogs in 

 the middle of the winter. This is expensive, but the difterence of a few cents for 

 each pupil is of no consequence in comparison with the benefit obtained from 

 the careful individual study of so good a type, at the close of their all too brief 

 introduction to zoology. Henry R. Linville. 



DeWitt Clinton Hish School. 



Demonstration of Phototropism in Aquatic Plants. 



At the close of the school year last June, an aquarium jar of fresh Philotria 

 (Elodea) was covered over with a glass plate to preserve it, and placed on the 

 sill of a south-facing window. The jar was not touched until the September 

 following. When it was examined, the stems of the still vigorous plants were 

 found to be nearly parallel, and with all the tips extended upward and toward 

 the source of light. The reaction of mustard seedlings to the same stimulus is 

 not more marked or beautiful. C. Stuart Gager. 



N. Y. State Normal College. 



Methods for Growing Pure Cultures of Algae. 



The lack of some means whereby algae, particularly the unicellular forms, 

 can be successfully isolated and cultivated in a pure state, has led to some most 

 remarkable theories with regard to the life history and affinities of certain spe- 

 cies. The tendency for one to become an ardent " polymorphist," after study- 

 ing the contents of a small jar from a single locality, was perhaps excusable at 

 one time, but that such crude methods should be retained and serious morpho- 

 logical and systematic work attempted under such conditions hardly seems nec- 

 essary in the present day. The following described media have been employed 

 in an attempt, still in progress, to monograph the unicellular green algae, where 



