36 Causes of Disease. 



1. Disturbances of Nutrition and Alimentation: Abnormal 

 states of nutrition depending on irregularity in the water or nutri- 

 tive elements afforded. 



2. Obstructions to Respiration: Interferences with oxygen 

 convection. 



3. Functional Disturbances: Depending upon fatigue, upon 

 overexercise of the organs. 



4. Thermic Influences: High or low temperatures. 



5. Electric Agencies. 



6. Mechanical or Traumatic Agencies. 



7. Chemical or Toxic Agents: Poisons. 



8. Microbic or Infectious Agents: Micro-organisms belong- 

 ing to the protopbytes and protozoa. 



9. Animal Parasites: Of the class of worms and arthropoda. 



Disturbances of Alimentation and Nutrition. 



Total deprivation of food without water supply (complete in- 

 anition) leads, in case of the higher vertebrates, to rapid loss of 

 bodv-weight. emaciation and death in the course of from one to 

 four weeks. A\'ith absolute rest (as in case of imprisonment in 

 a caved-in mine) an adult man may retain life without food and 

 drink for about twenty days : exertion hastens the end. Strong 

 dogs have lived under similar conditions for thirty-six days ; 

 horses and cats should live for about four weeks with absolute 

 rest. Guinea-pigs and rats die within three to nine days. Liberge 

 states that a well-conditioned cow. which had wandered into an 

 out of the way place and had remained there forty days without 

 food and without opportunity for much exercise, picked up 

 quickly on a milk diet and was in tolerable condition eight days 

 after being set free. 



If water is obtainable abstinence from food can be endured 

 without permanent harm by man and carniverous animals for 

 from two to four weeks, and the fatal end may be postponed for 

 a considerably longer period. A cat experimented on by Bidder, 

 weighing two and one-half kilograms, died on the eighteenth day 

 from star\-ation after having lost 1,197 grams (water consumed, 

 131. 5 grams). Birds of prey (eagle) endure hunger and thirst 

 for twenty to twenty-eight days; small birds only two to nine 

 days, rvlascagni has recorded a turkey's having fasted for twenty- 

 nine days. In case of cold-blooded animals the requirement for 

 food is so small that water-salam.anders and turtles mav live for 



