490 The Controversy on Spontaneous Generation ; [Oct., 



had risen considerably, and I then examined the tubes. (It should 

 be added that I had in the meantime added distilled water to that 

 in the open tube to compensate for evaporation.) 



The exposed water contained numerous zoospores, and uni- 

 cellular forms. Some of these were quiescent and attached toge- 

 ther in clusters ; others in active motion. There were some small 

 amoebae, small particles of protoplasm, with elastic cell-walls, well 

 known to micro-zoologists. In these, not only the characteristic 

 changing prolongations were visible, but I clearly followed the 

 rhythmical movements of the contractile vesicle. From the other 

 tube, the cotton-wool appeared to have excluded the dust and 

 germs* — the former having collected on the cotton, for I found no 

 organisms of any kind. It is right, however, to mention that 

 cotton- wool does not permanently exclude the germs; and in an- 

 other case, where the conditions of development were favourable (if 

 the view be correct that they are conveyed by the atmosphere), it 

 will be found that the substance referred to failed to exclude them. 



As to my saucers of distilled water, on going to examine them 

 I found the contents dried up, but a considerable quantity of dust 

 remained. This I scraped together; retained it until my return 

 from a journey on the 19 th July, and then submitted it to the 

 following process in the laboratory of my friend Mr. Tate, of Liver- 

 pool, aided by his assistant : — 



First we heated the dry dust in an open tube to 480° C, and 

 then, allowing it to cool, we heated it again to 280° 0. It had 

 then caked, and after loosening it with a wire we added distilled 

 water, and boiled it for a few minutes. Then I closed the tube 

 containing the liquid temporarily with a little stopper of cotton- 

 wool. 



The same evening, on examining the sediment with a power of 

 200 diameters, I observed many of the appearances described by 

 investigators who have opened infusions after they have been kept 

 in vacuo several days ; some, for example, similar to those described 

 by Dr. Bastian in his first experiment recorded in ' Nature ' of 

 July 7th. But I did not feel justified in attributing the movements 

 of the particles to their being endowed with life. 



I then divided the chief part of the water containing the dust 

 into two tubes, closing one with cotton-wool and leaving the other 

 exposed, and a little of it was left in an open wine-glass. The open 

 tube I examined on the 22nd, 23rd, and 24th July. The tempe- 

 rature was very high — 82° in the shade — and the development of 

 the little Cercomonas, so frequently described by me in former 

 years* was very rapid, so that on the 25th its movements were 

 clearly traceable amongst other lowly types. 



The water in the wine-glass was again dried up, but the effect 



* ' Journal of Science/ vol. i., p. 607, and elsewhere. 



