582 FRAGMENTS OF SCIENCE. 



were exposed should include those previously alleged to be 

 efficient. The conditions laid down by the heterogeuist 

 were accurately copied, but there was no corroboration of 

 his results. Stress was then laid on the question of warmth, 

 thirty degrees being suddenly added to the temperatures 

 with which both of us had previously worked. Waiving 

 all protest against the caprice thus manifested, I met this 

 new requirement also. The sealed tubes, which had 

 proved barren in the Royal Institution, were suspended in 

 perforated boxes, and placed under the supervision of an 

 intelligent assistant in the Turkish Bath in Jermyn street. 

 From two to six days had been allowed for the generation 

 of organisms in hermetically sealed tubes. Mine remained 

 in the washing-room of the bath for nine days. Ther- 

 mometers placed in the boxes, and read off twice or three 

 times a day, showed the temperature to vary from a mini- 

 mum of 101 degrees to a maximum of 112 degrees Fahr. 

 At the end of nine days the infusions were as clear as at 

 the beginning. They were then removed to a warmer 

 position. A temperature of 115 degrees had been 

 mentioned as particularly favorable to spontaneous gener- 

 ation. For fourteen days the temperature of the Turkish 

 Bath hovered about this point, falling once as low as 106 

 degrees, reaching 116 degrees on three occasions, 118 

 degrees on one, and 119 degrees on two. The result was 

 quite the same as that just recorded. The higher 

 temperatures proved perfectly incompetent to develop 

 life. 



Taking the actual experiment we have made as a basis 

 of calculation, if our 940 flasks were opened on the hayloft 

 of the Bel Alp, 858 of them would become filled with 

 organisms. The escape of the remaining 82 strengthens 

 our case, proving as it does conclusively that not in the air, 

 nor in the infusions, nor in anything continuous diffused 

 through the air, but in discrete particles, suspended in the 

 air and nourished by the infusions, we are to seek the 

 cause of life. Our experiment proves these particles to be 

 in some cases so far apart on 'the hayloft as to permit 10 

 per cent, of our flasks to take in air without contracting 

 contamination. A quarter of a century ago Pasteur proved 

 the cause of "so-called spontaneous generation" to be 

 discontinuous. I have already referred to his observation 

 that 12 out of 20 flasks opened on the plains escaped 



