CHAPTER X. 

 ANIMAL INOCULATION. 



Section I. The selection of animals for inoculation, p. 156. 



Section II. The keeping of animals, p. 157. 



Section III. The spontaneous diseases of experimental animals, p. 159. 



Section IV. The handling of experimental animals, p. 160. 



Section V. Experimental inoculations, p. 165. 



1. Instruments, p. 165. 2. Preparation of the material for inoculation, p. 169. 

 3. Technique of inoculation, p. 170. 

 Section VI. Observations to be made on inoculated animals, p. 182. 



SECTION I. THE SELECTION OF ANIMALS FOR INOCULATION. 



FOR purposes of experimental inoculation, animals are chosen preferably 

 from among the mammalia, less frequently from among the other vertebra ta. 

 In deciding upon what species of animal shall be used for a given experiment 

 there are of course various considerations which must be taken into account. 



1. Susceptibility. In the first place it is obviously necessary to select a 

 species of animal suitable for the experiment in view. To produce a given 

 disease experimentally, an animal susceptible to the virus should, generally 

 speaking, be chosen, though it is sometimes desirable to use an animal immune 

 to the particular disease and to destroy its immunity in some way or another. 

 Some knowledge, therefore, of the diseases to which animals available for 

 experimental purposes are susceptible is more or less indispensable. In 

 subsequent chapters those animals which are susceptible to the action of the 

 principal micro-organisms will be mentioned. When a new organism is 

 under investigation and its pathogenic properties have to be determined it is 

 desirable to inoculate as many different species of animals as possible. 



2. Economic considerations. In the majority of cases small animals are 

 used ; they are cheap to buy, and can be kept and fed at small expense, 

 and, if need be, can be bred in the laboratory. 



3. General considerations. Whenever possible animals of quiet habits are 

 chosen because they are easy to handle, and do not require elaborate cages. 



Small rodents, such as rabbits, guinea-pigs, white mice, white rats, common 

 brown mice [Mus musculus], and house rats [Mus decumanus] are, on the 

 whole, more often used than any other animals for experimental inoculation ; 

 they are easily obtained, and the first four to which the term " laboratory 

 animals " generally refers are susceptible to most of the organisms patho- 

 genic to man. 



Cattle, goats, pigs, horses, sheep, asses and birds (fowls and pigeons) are 

 also used for experiment in special cases. 



