and Laboratory Methods. 



2307 



Work with the living crayfish is always profitable, and I might say, boisterously 

 interesting. We employ glass and porcelain-lined trays ten to fourteen inches 

 long and two and one-half inches deep, filled with water. With an active cray- 

 fish in one of these, two pupils working together can observe definitely the 

 mechanics of locomotion ; by the aid of carmine poured upon the upturned 

 ventral surface the manner of flowing and the rapidity of the current which 

 passes through the gill chamber can be seen, as the animal is returned to the 

 water; responses of the sense organs to stimuli can be obtained without the use 

 of corroding chemicals. This study may well take two periods to complete. 



Fig. 3. 



We have recently inaugurated a plan for the presentation of the facts of 

 nutrition, with a view toward leading up to the understanding of human physiol- 

 ogy. The problem of the corelation of human physiology with elementary] zo- 

 ology is by no means as simple as it is sometimes supposed. Scientifically, 

 human physiology has no more place in a course of elementary zoology than 

 comparative embryology has. By uniting elementary zoology and human 

 physiology we comply with a State law in reference to the teaching of physiol- 

 ogy, and also save time for some other subject in the high school curriculum. 



