CHAPTER VI 

 METHODS OF ANIMAL EXPERIMENTATION 



Value of Animal Experimentation. — The importance of ex- 

 perimentation upon animals in the development of our knowledge 

 concerning disease-producing micro-organisms can hardly be 

 over-estimated, and animals must be used in considerable numbers 

 in any adequate presentation of the subject to a laboratory class 

 in pathogenic bacteriology. Only in this way has it been possible 

 to discover the causal relation of bacteria to disease and the way 

 in which diseases are transmitted, and it is only by the use of 

 animals that this information can be presented first-hand to 

 students. The inoculation of animals also provides accurately 

 controlled material for studying the course and termination of 

 the disease as well as the gross or microscopic lesions produced 

 by it. 



Care of Animals. — ^Laboratory animals should be housed in a 

 light, well-ventilated room which should he heated in winter to 

 about 60° F. If possible a run-way in the open air should be 

 provided. The fixed cages may be constructed with wood or 

 steel frames, but at least the front and preferably both front and 

 back should be made of strong wire netting to provide ample 

 ventilation. For rats and mice it is well to provide an enclosed 

 perfectly dark space inside the cage into which these animals 

 may retire. Smaller movable cages must also be provided for 

 animals acutely sick and those infected with dangerously com- 

 municable diseases. These must be steriHzable, and wood should 

 not be used in their construction. Glass jars with weighted 

 covers of wire netting are useful for mice and rats, and for larger 

 animals such as guinea-pigs, rabbits and cats, cages of galvanized 

 iron and wire netting are used. Pigeons may also be kept in such 



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