M. H. Hoffmann on Fermentation. 275 



tube in as oblique a position as possible. The spores, which 

 contain air, and are therefore specifically very light, rose as 

 usual ; but instead of meeting the air, they came in contact with 

 the wall of the tube, and often remained immersed in the fluid. 

 The tube was agitated once a day ; and as early as the second or 

 third day a mycelium was developed around the spores, and at 

 this point, and then only, an evolution of gas commenced. From 

 this time the tube had to be shaken more frequently. This ex- 

 periment, modified in many different ways, proves that the de- 

 velopment of the gas is intimately connected with the vegetation 

 of the Fungus. In course of time the liquid becomes acid, and 

 the evolution of gas ceases. If it be examined by the microscope, 

 besides a few fructiferous filaments (in their atypic state), it is 

 found to consist of mycetoid filaments and spores in various 

 stages of germination, besides a great many yeast-cells in all 

 phases of development. 



A fermentation of greater or less strength may be produced 

 not only with the spores of Penicillium, but also with those of 

 other Fungi. M. Hoffmann succeeded in setting up fermenta- 

 tion in fresh wort, in grape-sugar, cane-sugar, and boiled goose- 

 berry juice, by adding to the fluids spores of Ustilago carbo, 

 Ascophora mucedo, and Stachylidium pulchrum, and also by 

 putting in rose-leaves infected by Phragmidium incrassatum, and 

 Uredo Rosce, and finally by means of Torula fructigena, Pers. 

 The dust collected on books also produces fermentation. The 

 liquid at first contains yeast and a greater or less number of 

 Bacteria ; finally, Penicillia or Ascophora are developed on its 

 surface. 



The yeast thus artificially produced has all the physical and 

 chemical properties of the ordinary yeast of the juice of raw 

 fruits. M. Hoffmann has even made leaven with yeast produced 

 by means of the Fungi of the Rose. On the other hand, he 

 never succeeded in producing fermentation or the formation of 

 yeast by means of fresh spores of Agarics or Boleti. From this 

 it follows that all Fungi cannot assist in the production of yeast. 

 This property appears to depend upon their capacity of forming 

 conidia by their filaments of germination, and also perhaps upon 

 the fact of their having been produced upon parts of plants in 

 good health, or dead or dying. M. Hoffmann is inclined to think 

 that this property of decomposing and penetrating deeply into 

 the surrounding fluids is due especially to the mycetoid fila- 

 ments. 



And now the question presents itself, what part do Fungi and 

 Infusoria take in the decomposition and putrefaction of organized 

 bodies ? 



If certain Fungi (and Infusoria) alone possess the property of 



