ELIMINATION OF WASTES 197 



2. Excretion in one-celled organisms 



Materials 

 How put out 



3. Excretion in larger plants 



Through leaf ; through stem ; through root 

 (Through locking up in inactive tissues) 



4. The kidneys and bladder 



Structure Function 



Tubules and capillaries Elimination of wastes in 



Funnel liquid form 



Ureters Hygiene 



Bladder Water supply for body 



Urethra Elimination of urine 



5. Importance of condition of urine as index of condition of body 



QUESTIONS 



1. How do waste products originate in an organism ? 



2. What waste products of metabolism are harmless to protoplasm ? 

 What products are injurious ? 



3. What organs in a one-celled plant are analogous to the kidneys ? 



4. What are the advantages of taking all the water needed for the day 

 at one drinking ? What are the disadvantages ? 



5. Of what concern is it to the public whether stores and workshops 

 provide suitable toilets ? 



REFERENCE READINGS 



McCarthy, J. D. Health and Efficiency, chap. xv. 



Hough and Sedgwick. The Human Mechanism, pp. 180-183. 



