M. Dutrochet mi the Origin of Mouldiness. 309 



distilled water, and put it into a flask. This liquid was pre- 

 served for a whole year, both exposed to the light and put into 

 the dark, but it never exhibited the least trace of the thallus of 

 mould. It did not even develope a single atom o^ greenish mat- 

 ter. Thus, it has been indisputably demonstrated, that this 

 albuminous liquid is wholly unfit for the production or the nu- 

 trition of the vegetable infusores. I then took six flasks, into 

 each of which I put an ounce of water, mixed with albumen as 

 above, and to each of them I added one drop of an acid. The 

 acids employed were the sulphuric, nitric, muriatic, the phos- 

 phoric, acetic, and oxalic. In less than eight days, the thallus 

 of mould appeared in the whole six flasks. These thai! uses 

 were simultaneously produced at the bottom and sides of the 

 vessels, and were observed to develope themselves in concentric 

 rays. I then took some of each of these thalluses, and I pro- 

 ceeded in the way described above, so that I might produce 

 their aerial moulds, and they all, without exception, produced 

 monilia of different kinds. ir. 



Into separate flasks, containing the same albuminous water, 

 I put severally equal quantities of caustic potash, and soda, in 

 the proportion of 0.005 to the weight of the water. In both 

 the thallus of mould appeared, but it was not till about the end 

 of three weeks. In the aerial growths of these thalluses I could 

 only discover Botrytis of various kinds. 



It would result from these experiments, that the acids exclu- 

 sively favour the production of the monilia, whilst the alkalies 

 conduce only to the production of the botrytis. But these re- 

 sults are not constant. They are altered by the employment of 

 other organic substances than albumen. Thus, if to distilled 

 water there be added a small quantity of aqua potassa, in which 

 ^a little of the fibrin of the blood is dissolved, this liquid gives 

 origin to thalluses, which produce monilia. I have also seen, 

 that when phosphoric acid is added to the distilled water of let 

 tuce, the liquid gives origin to the thalluses of botrytis. In this 

 last experiment, there was in the water no other organic sub- 

 stance but that which had passed over with it in the distillation. 

 I have observed that this distilled water of lettuce, pure and 

 abundant in itself, deposits in the bottom of the vessels in which 

 it is contained a while substance, which is entirely composed of 



