and Laboratory Methods. 2543 



The Fehling's solution test for grape sugar can be performed at home, the 

 necessary chemicals and test tubes being furnished the pupil. The presence or 

 absence of proteids, fats, mineral matters, and water should likewise be experi- 

 mentally determined at home or in the class by the individual pupil, and a 

 comparison made of the results obtained. Each pupil has now a concrete idea 

 of some of the most important compounds he is to meet continually as ingre- 

 dients of his food, as components of his blood, or as essential constituents of 

 his body. 



It is impossible of course to demonstrate by experiment the uses of the 

 various nutrients, and so with laboratory study there must be combine'd a con- 

 siderable amount of class room recitation. Indeed, we should bear in mind that 

 laboratory work must always be followed with and supplemented by vigorous 

 questioning ; a process which keeps clear in the mind of the pupil the essential 

 points in each experiment and the relations of the various facts that have been 

 learned. 



The uses of foods, proper methods of cooking, and the study of food economy 

 are, to my mind, among the most important of the topics connected with human 

 physiology. These subjects are treated more or less inadequately in most school 

 text-books, but fortunately the publications of the United States Department of 

 Agriculture are available even in the large quantities required for individual 

 study. The best bulletins for high school use are " Foods : Nutritive Value and 

 Cost," and " Meats : Composition and Cooking." The colored food charts 

 which are so useful in class recitations are unfortunately out of print, but the 

 charts and tables in the bulletins named above can be used to almost as good a 

 purpose. 



A study of half a dozen of the common tissues should next be undertaken, 

 because these tissues are met with again and again in considering the processes 

 of digestion, circulation, and respiration. Get a butcher to saw in halves the 

 leg bones of a sheep, supply each pupil with a half bone, and a dissecting knife. 

 At the close of fifty minutes of laboratory work, he should have learned the 

 essential characteristics of bone, cartilage, connective tissue, and fatty tissue. 

 Another laboratory period spent in studying pieces of beefsteak will fix in mind 

 muscle tissue and will serve to review fat and connective tissue. It is perhaps 

 best to reserve the discussion of glandular tissue, nerve tissue, and respiratory 

 tissue until a later time. 



The study of cell structure and cell functions should now be introduced, and 

 two or three days may well be spent at this time on Amoeba and Paramecium. 

 The pupil should be led to see that these single celled animals carry on processes 

 essentially the same in kind as those performed by the highest animals, and it is 

 well perhaps to consider, in the following order, the ten most important functions 

 carried on by animal cells : (1) locomotion, (2) taking in of food, (3) digestion, 

 (4) circulation, (5) assimilation, (6) taking in of oxygen, (7) oxidation or meta- 

 bolism, (8) excretion, (9) sensation, and (10) reproduction. 



Let me take a little time to suggest some methods that have been found 

 effective in this laboratory study in the classes of a large school. While it is not 

 impossible to do this kind of work even when the teacher has to go from room 



