1870.] with Recent Experiments. 493 



and preparing for this, and at once proceeded to catch the rain as 

 it fell, and at the same timo to prepare an infusion of filtered 

 orange-juice in pure distilled water. This infusion I divided 

 between two glass-wells, one of which I closed with cotton-wool, 

 whilst the other was freely exposed to the atmosphere ; and side 

 by side with these I placed a tall champagne glass full of the rain- 

 water which I had collected during the shower, and which contained 

 numerous particles of dust. 



None of these liquids showed any undoubted signs of life when 

 I examined them with the microscope, before exposure. The 

 infusion contained organic yellow particles ; the rain-water organic 

 particles, fragments of minerals, empty sheaths, empty cell-walls, 

 and minute moving specks. 



The very next day, however, August 5th, I was astonished to 

 find in the open infusion of orange-juice the mycelium figured 

 and described by Dr. Bastian as having been present in his infu- 

 sion of turnips, or one closely resembling it; and in my infu- 

 sion it was accompanied by innumerable minute unicellular oval 

 organisms, the careful examination of which satisfied me beyond 

 a doubt that they were an earlier stage of the thread-like filaments. 

 Some of them were single, others were undergoing subdivision into 

 two or more segments, whilst on the other hand some of the fila- 

 ments were giving off cells exactly resembling the smaller detached 

 ones. 



During a long course of microscopical observation of biological 

 changes, I never was so much astonished as on that occasion to find 

 with what rapidity Nature (or that I may not be misunderstood — 

 Nature's Ruler) brings back to active life the decomposing materials 

 which have been its previous stronghold ; and had I been led away 

 by momentary impressions I could not have conceived it possible that 

 the change had been produced in that case by any other process than 

 heterogenesis, or the elevation of a portion of the organic infusion 

 into organized types, without the auxiliary influence of pre-existing 

 germs. But a little reflection reminded me that it is just these 

 first surprises and impulses which lead men to disseminate erroneous 

 views, as it was no doubt the extraordinary appearance of maggots 

 and flies on some decaying carcase which gave rise to the idea of 

 those insects being spontaneously generated there. I therefore 

 contented myself with figuring the cells and the mycelium as they 

 appeared under varying powers of the microscope on the day in 

 question and the four following days (Figs. 1 and 2), and during 

 that time the mycelium gradually developed into a true mould or 

 mildew fungus, some of which floated on the surface. At the same 

 time numerous ciliated infusoria made their appearance. 



On the 9 th August I opened the other glass-well containing 

 the infusion, and found it covered in like manner with mildew. I 



2 l 2 



