BLAIR'S OBSERVATIONS 27 



M. JNIagendie demonstrated that a few drops of putrid 

 fish inoculated into animals produce very severe intoxi- 

 cation. Then he says, " N'est-ce pas, en efFet, une 

 instillation de poisson en putrefaction que ^■ersent ces 

 insectes sous la peau et dans le tissu cellulaire de 

 I'homme ? " 



Thus Beauperthuy was clear as to the transmitting 

 agent, but fell into error in supposing that the poison 

 was taken from extraneous decomposing matter, and 

 not from the infected man. In other words, he 

 believed that the poison was telluric, that it did not, 

 however, come off in the form of a gas or miasm, 

 but was carried and inoculated into man through the 

 instrumentality of a mosquito. 



Another investigator of high repute, and also of 

 British Guiana, ^iz. Surgeon-General Daniel Blair, 

 writes in 18.52, in his "Report on the First Eighteen 

 Months of the Fourth Yellow Fever Epidemic of 

 British Guiana," that — 



" it would appear from the observation of the present 

 epidemic that though, as is well established, a certain 

 high average temperature is required for the generation 

 and continued existence of the efficient cause of yellow 

 fever, it has not its genesis from any known combina- 

 tion of meteorological elements, and may appear at 

 a time when they are highly favourable to general 

 health and comfort ; that the laws of its diffusion differ 

 from those of gases ; that it is impelled by atmospheric 

 currents, but seems to possess some power of spon- 

 taneous motion ; that though intense energy of vegeta- 

 tive power characterised the seasons antecedent to and 



