cxxxn THE BEGINNINGS OF LIFE. 



dental feature, and that there is no real difference in kind 

 between the poison of a serpent which does not occasion 

 the production of a similar venom, and the poison of a 

 mad dog which does lead, directly or indirectly, to the re- 

 evolution of a similar virus 1 . 



Let us take a brief survey of some of the facts which are 

 known concerning these specific infective diseases. 



Glanders is an affection which is in many respects 

 analogous to syphilis, and is almost, if not quite, as highly 

 contagious a malady. Both these diseases, too, form ex- 

 tremely interesting links between such specific tissue affections 

 as cancer and tubercle, and such infective blood-diseases as 

 small- pox and scarlet- fever. Like the former, they are apt 

 to involve the presence of morbid growths scattered in 

 different parts of the body, though, like the latter, they are 

 commonly spread by contagion from individual to individual. 

 However little we may know concerning the actual origin of 

 syphilis, no doubt seems to remain in the minds of most of 

 those who have studied the question, as to the possibility 

 of producing glanders in the horse. After referring to the 

 highly contagious nature of the affection, Dr. Gavin Milroy 



1 In snake-bite the symptoms are due to the effects of an habitually 

 poisonous secretion which has a most rapid and deadly action ; whilst 

 hydrophobia is due to the effects of an occasional quality of the salivary 

 secretion. This occasional quality, characteristic of rabies, is generally 

 admitted to arise independently in the dog, and yet the poisonous 

 salivary secretion sets up a similar disease in other dogs which may be 

 bitten. Nay, more, this affection at times prevails in an epidemic 

 fashion. Dr. Gavin Milroy says (' Transactions of the Epidemiological 

 Society,' vol. i. p. 173): ' Hillary, in his work on Barbadoet,, described 

 rabies as common in the West Indies. Moseley, having never seen a 

 case of it for a series of years, doubted the correctness of the statement ; 

 but, in 1 783, it unexpectedly broke out with violence at Hispaniola, and 

 also in Jamaica, where it prevailed from June to the following March. 

 Dogs were seized with it that had no communication with others, and 

 some dogs not brought on shore went mad in the harbours of the island. 

 " On Tropical Diseases," 180,;.' There are those, however, who still 

 doubt whether rabies is capable of arising de novo. (See Art. in 

 Reynolds's ' System of Medicine,' vol. i.) 



