ADMINISTRATION OF NAKCOTICS. 257 



to animals on whic'i we experiment, as their action must to a 

 certain extent complicate tliat of the drug wliich we wish to 

 investigate. We cannot i^se them when we are observing what 

 are the general symptoms wliich a medicine produces. But, 

 when we are investigating its action on particular organs, we 

 may often use them, not only with safety, but with advantage, 

 when they have no action on the particular organ which we are 

 studying, or so little that its disturbing influence is more than 

 compensated by the diminished muscular action, and conse- 

 quent ease in performing the experiment, which narcotics 

 produce. 



It is almost unnecessary to say that, in all cases which adiftit 

 of it, narcotics should be used, as we have no riglit to inflict 

 any unnecessary pain, although we may be justified in taking 

 the lives of tlie lower animals in order to preserve the more 

 valuable life of man, either by supplying him with food by 

 means of those killed in the slaughter-house, or by obtaining 

 the knowledge which shall enable us to cure disease by means 

 of those killed in our experiments. The narcotics which we 

 use are opium and chloral. Chloroform is inadmissible, as its 

 administration generally seems to cause dogs more pain than 

 the experiment itself, and rabbits are very easily killed by it.* 



A convenient form of giving chloral is a solution containing 

 half a grain in 1 minim or 1 gram in 2 c.c. of water. The 

 dose for a frog is 2 to 5 centigrams, or about 1 to 5 drops. 

 The dose for guinea-pigs is about 12 minims of this solution 

 for an animal half a pound weight; and more or less may 

 be given, according to the weight of the animal, 18 minims 

 being given to one weighing three-quarters of a pound, and 24 

 to one weighing a pound. About the same proportion of dose 

 to w^eight may be employed for rabbits. 



Opium may be given in the form of laudanum, or of solution 

 of acetate or hydrochlorate of morphia. Much as it is used, 

 the proper dose for different animals has not been exactly de- 

 termined. We do not often employ it to narcotise guinea-pigs 

 or rabbits, but frequently for dogs. The dose for a medium- 

 sized dog is about 40 minims or 2-^ c.c. of laudanum, or 



* This statement is erroneous, vide -p. 336. 



