310 RESPIRATION AND EXCRETION 



Special Reports 



1. The bodily excretions. 



2. Causes of changes in the composition of blood. 



3. The cause of boils. 



4. Changes in the composition of the blood. 



References 



Hunter, Essentials of Biology. Chap. XXVII. 



Hunter, Elements of Biology. Chap. XXXIV. 



Davison, The Human Body and Health (Advanced). Chap. XVI. 



SUMMARY VI 1 



A final comparison of human body cells with a com- 

 munity, physiological division of labor. 



a. Division of Labor 



Observations. 1. Note the different varieties of cells shown 

 in Figure 46, from various parts of the body. Why may they 

 be called "tiny citizens of the body community 7 '? 



2. Name some cells that belong to the body community that 

 are not shown in the Figure. 



Conclusions. 1. Show how the red blood corpuscles of the 

 body may be compared to railroad men. Note. Why canals 

 instead of railroads in the body community ? 



2. How may the digestive cells be compared with farmers ? 

 Note. Keep in mind the work of the farmer in converting 

 crude soil into things suitable for man's consumption. 



3. How may you compare the colorless or white blood corpuscles 

 with soldiers and policemen ? 



4. Show how nerve cells may be compared with governors 

 and teachers. 



5. Compare cells in the skin and kidneys with scavengers. 



6. What may the muscle cells be compared to in a human 

 community ? 



1 The field work for Problem LVI, II, Sanitary Map, and Sanitation should 

 now be started. 



