2308 



Journal of Applied Microscopy 



The demonstration dissections of the locust and the crayfish give the pupils 

 some knowledge of the way food is disposed of. Ingestion and digestion are 

 discussed and explained by lectures, experiments and recitations. Application 

 of what is learned in that way is made to the more complicated conditions in the 

 human digestive organs and physiological processes. At some time in the two 

 weeks given to the annelids, the next two stages in nutrition are explained. The 

 earthworm is unusually favorable for simplifying the ideas of absorption and 

 circulation. The intestine is a simple tube, and the circulatory system is clearly 



Fig. 4. 



defined. Experiments on osmose are made simple to help in explaining absorp- 

 tion in the time we have set aside for the clam. 



Tracheae, gills, and and lungs are then discussed as organs which cooperate 

 with the circulatory system, to transport liquid and gaseous food to the tissues. 

 Assimilation, or the synthesis of protoplasm, must, because of its nature, be left 

 only partially understood. Oxidation and the release of energy are, I am sure, 

 never thoroughly comprehended by a beginner. The idea is too complex for 

 one with no intellectual perspective. However, our faith in the usefulness or 



