66 Royal SocieUj. 



in five days, and an increase in ten, instead of requiring twenty-four 

 days, as was the case when pure water only was employed. 



Albumen therefore facilitated the development of life. Of course 

 the contents of the flask were examined at the same time ; but in no 

 instance was life detected. I believe that these three series of expe- 

 riments tend to prove the fallacy of the theory of spontaneous gene- 

 ration ; for if it were possible, why should not life have appeared in 

 the pure distilled water, or in the albuminous solution, which were 

 kept successively in the flask B, as well as in the fluids which were 

 contained in the tubes, and had been exposed to the atmosphere or 

 near animal matter in a state of decay, and had thus become im- 

 pregnated with the germs of protoplasmic life ? What gives still 

 further interest to these experiments is, that, having operated during 

 the severe weather of last winter, when little or no life existed in 

 the atmosphere, I was able to impregnate the fluids with germs 

 without introducing developed life. 



The quantity of life produced in the above-recited experiments being 

 comparatively small, 1 was led to infer that this might be due to the 

 influence of the atmosphere of hydrogen employed to displace the 

 air in the apparatus used for obtaining the water. I therefore, on 

 the 2nd of March, prepared a solution of albumen similar to that 

 before employed, but expelled the air out of the apparatus by pure 

 oxygen ; and as the contents of tlte flask B were free from life on 

 the 8th of March, a series of small' tubes were filled and exposed 

 for twenty-six hours to the atmosphere near putrid matter, and 

 then sealed. Several of these tubes were opened on the 11th, and 

 immediately examined, when only a few cells were observed in each 

 field. A second lot was opened on the 14th; and they showed 

 considerable increase of life, there being two or three vibrios under 

 each field. A third quantity was opened on the 25th, when no 

 increase had taken place. This latter result tends to show that 

 although oxygen appears to favour the development of germs, still it 

 does not appear to favour their reproduction. 



As the weather had become much warmer, and a marked increase 

 of life in the atmosphere had taken place, some of the same albumen 

 solution as had been employed in the above experiments was left 

 exposed in similar tubes to its influence, when a large quantity of 

 life was rapidly developed and continued to increase. This result 

 appears to show that the increase of life is not due to reproduction 

 merely, but to the introduction of fresh germs ; for, excepting this 

 fresh supply, there appears to be no reason why life should increase 

 more rapidly in the open than in the closed tubes. 



In concluding this paper I have great pleasure in recognizing the 

 able and persevering attention with which my assistant, Mr. William 

 Thompson, has carried out these experiments. 



