418 BACTERIA IX INFECTIOUS DISEASES. 



reconcilable. In support of this I will first submit a 

 few concise propositions which seem to me capable of 

 proof, and will then briefly discuss these propositions, 

 and the legitimate inferences to be drawn from them : 



" 1. The yellow fever poison is not an emanation from 

 the persons of those sick with the disease. 



" 2. It is not generated by atmospheric or telluric influ- 

 ences. A certain elevation of temperature is, however, 

 necessary for its multiplication ; and its rapid increase is 

 promoted by a moist atmosphere, and probably by the 

 presence of decomposing organic matter. 



" 3. The poison is portable in ships, goods, clothing, etc., 

 and a minute quantity is capable of giving rise to an exten- 

 sive epidemic. 



" 4. Exposure to a temperature of 32 Fahrenheit com- 

 pletely destroys it. 



" 5. It may remain for an unknown length of time in a 

 quiescent state, when not subjected to a freezing temper- 

 ature, or exposed to the conditions necessary to its mul- 

 tiplication, and may again become active and increase 

 indefinitely when those conditions prevail. 



" If the first three propositions be proven, viz., that 

 the poison is portable, that a small quantity may in- 

 crease indefinitely, independently of the human body, 

 and that it is not produced by atmospheric influences, 

 then the necessary inference is, that it is capable of self- 

 multiplication, which is a property of living matter 

 only." 



The propositions above stated were supported, in 

 the paper referred to, by facts observed during 

 a local epidemic, which occurred on Governor's 

 Island, New York harbor, during the summer of 

 1870. Other local epidemics, since observed by 

 the writer, and the recorded facts relating to nu- 



