PART I.] Injection of Choleraic Fluid into Veins of Animals. 83 



cholera-material hitherto recorded, and which have exercised great influence on the 



opinion of medical writers, and of the scientific world generally, have for the most 



part been derived from experiments on even more delicate animals than those above 

 referred to. 



This drawback will be evident to all who may carefully peruse some of the 

 following cases, more especially those recorded in connection with the attempts to 

 produce infection by the introduction of choleraic and other organic matters into the 

 circulation. 



The unsuitableness of small animals for experiments involving section of minute 

 and deep-seated nerves arises, to a great extent at least, from a different cause, 

 namely, the extreme tenuity of nerve fibres in such, which in man are large and 

 easily accessible, and are even moderately large in well-developed dogs. Size is of 

 still more importance, where, as in remarkable cases to be afterwards referred to, 

 the section of a certain portion of a nerve appears to make such a vast difference in 

 the result of the experiment. 



We have, therefore, selected the dog not only from its size, but also from the 

 fact of its food being very closely allied to that of man, as being more suitable 

 to experiments of the nature here alluded to, especially as the organic substances 

 hitherto experimented upon have not been introduced in the circulation through 

 the digestive system. Had such a method been adopted, the tremendous powers of 

 digestion of the native pariah or Bedouin dog would have rendered any comparative 

 data unmistakably useless.* Added to this, the numbers obtainable and with tolerable 

 ease (these dogs being under the ban of the Police here), it will be evident that, taking 

 all things together, they are the most suitable animals for systematic investigation 

 of this nature. 



A.— Experiments on the injection of choleraic and other organic fluids into the 



veins of animals. 



In order to judge of the validity of generalizations derived from any such series 

 of experiments as that included under the above heading, it is clearly necessary that 

 the precise grounds for these should be known. We shall therefore, in the first place, 

 proceed to give a brief abstract of the results of various cases, condensed from notes 

 taken at the time, and shall then proceed to draw any conclusions from them which 

 the data appear in our estimation to warrant. 



We are the rather inclined to such a course, seeing that almost any series of 



* We purpose, however, availing ourselves of an early opportunity of trying the effect of injecting 

 various substances directly into the small intestines of animals, by taking out a loop of the gut, and introducing 

 the selected substance by means of a finely pointed syringe ; thus overcoming this source of fallacy, at least as 

 far as the direct action of the stomach is concerned. 



