RESPIRATION AND EXCRETION 347 



materials, hence it takes away oxygen that would otherwise be 

 used in oxidizing these foods. Imperfect oxidation of foods 

 causes the development and retention of poisons in the blood 

 which it becomes the work of the kidneys to remove. If the kid- 

 neys become overworked, disease will occur. Such disease is likely 

 to make itself felt as rheumatism or gout, both of which are be- 

 lieved to be due to waste products (poisons) in the blood. 



Poisons produced by Alcohol. - - When too little oxygen enters the 

 draft of the stove, the wood is burned imperfectly, and there are 

 clouds of smoke and irritating gases. So, if oxygen unites with the 

 alcohol and too little reaches the cells, instead of carbon dioxide, 

 water, and urea being formed, there are other products, some 

 of which are exceedingly poisonous and which the kidneys handle 

 with difficulty. The poisons retained in the circulation never fail 

 to produce their poisonous effects, as shown by headaches, clouded 

 brain, pain, and weakness of the body. The word " intoxication ' 

 means " in a state of poisoning." These poisons gradually accumu- 

 late as the alcohol takes oxygen from the cells. The worst effects 

 come last, when the brain is too benumbed to judge fairly of their 

 harm. 



REFERENCE BOOKS 



ELEMENTARY 



Hunter, Laboratory Problems in Civic Biology. American Book Company. 

 Davison, Human Body and Health. American Book Company. 

 Gulick, Hygiene Series, Emergencies, Good Health. Ginn and Company. 

 Hough and Sedgwick, The Human Mechanism. Ginn and Company. 

 Macy, General Physiology. American Book Company. 

 Ritchie, Human Physiology. World Book Company. 



