XVIII. THE HUMAN MACHINE AND ITS NEEDS 



Problem. To obtain a general understanding of tJie parts 

 and uses of the bodily machine. 



LABORATORY SUGGESTIONS 



Demonstration. Review to show that the human body is a complex 

 of cells. 



Laboratory demonstration by means of (a) human skeleton and (6) 

 manikin to show the position and gross structure of the chief organs of 

 man. 



To THE TEACHER. As in certain of the previous chapters, the student here 

 takes a preliminary view of the general problem that lasts for the rest of his course 

 in biology, i.e., that of adaptation to function in the human body. A general sur- 

 vey gives an initial interest in problems which are solved later ; it defines the future 

 problems and marks the beginning of some new concepts. Certain structures of 

 the body, as, for example, bones and muscles, are now treated and dismissed, not 

 because of their non-importance, but because of the time demanded by the more 

 practical questions relating to dietaries and bodily nutrition. 



Problem 163: To show that the human body is made up of 

 cells. 



Materials. Scalpel, methyl blue, glass slides, cover glasses, 

 microscope. 



Method. Scrape mucous lining from the mouth, mount on 

 a glass slide, and stain with a drop of dilute methyl blue. Cover 

 with cover glass and examine under microscope. 



Observations. The large irregular bodies with dark blue 

 bodies within them are flat cells (epithelium) from the lining of 

 the mouth. What are these dark blue structures within the cell? 

 (The small dots or rods stained deep blue are bacteria.) 



Cells from other parts of the body, gland, muscle, nerve, etc., 

 should be demonstrated under the compound microscope. 



Conclusion. What are the units of building material in the 

 body? 



187 



