24 THE MOSQUITO ORIGIN OF DISEASES 



study It oil the spot. AVe thus find him at Cuniana 

 in Venezuela, where a virulent epidemic had broken 

 out. In Cumanii he appears to have been made a 

 health officer by the then Government, and in 1853 

 we find him contributing a paper to the Gaceta Oficial 

 cic Cumand, in which he says : 



" To the work I undertook I brought the knowledge 

 gained during fourteen years' microscopic observation of 

 the blood and secretions in every type of fever. These 

 observations were of great service to me in recognising 

 the cause of yellow fever and the fitting methods of 

 combating tliis terrible malady. A\"ith regard to my 

 investigations on the aetiology of yellow fever, I must 

 abstain for the present from making them public. 

 They form a part of a prolonged study, the residts of 

 which are facts so novel, and so far removed from all 

 hitherto accepted doctrines, that I ought not to publish 

 them without adducing fuller e\idence in support. 

 Moreover, I am sending to the Academic des Sciences 

 de Paris a communication which contains a summary 

 of the observations I have made up to the present, 

 tlie object of which is to secure the priority of my 

 discoveries concerning the cause of fevers in general. 



" The affection known as vellow fever, or black 

 vomit, is due to the same cause as that producing 

 intermittent fever. 



" Yellow fe\'er is in no way to be regarded as a 

 contagious disease. 



'• 'J'he disease develops itself under conditions whicli 

 favour the development of mosquitos. 



" The mosquito plunges its proboscis into the 

 skin . . . and introduces a poison whicli has properties 

 akin to that of snake Acnom. It softens the red blood 



