210 Mr. W. K. Sullivan on the nature of Lactic Fermentation, 



during which the whole of the oxygen must have been slowly used 

 in oxidizing the caseine? Then, again, no trace of yeast-globules 

 could be found in the milk when the bottle was opened ; but 

 after a few days mould and abundance of infusoria were developed 

 in the Uquid, partially neutralized by zinc. 



The growth of moulds, as for example the beautiful Penicillium 

 glaucum, from milk-globules has been long noticed. Indeed 

 Dutrochet states that he observed milk-globules changed into 

 the spores of mould, or at any rate developed into moulds. But 

 in all instances the growth of the fungi appears to have been 

 subsequent to the production of lactic acid. Turpin*, it is true, 

 supposed that the growth of P. glaucum might be the cause of 

 the knotted condition of an engorged breast, the germination of 

 the spores taking place in the undischarged milk in the lacteal 

 ducts. But there is no proof whatever that any such growth 

 ever took place in unaltered milk within the body. It is very 

 probable that Pasteur^s lactic yeast M'as nothing more than the 

 mycelium of Penicillium glaucum. 



If we recollect that the spores of some fungi are not more 

 than ro'j-o'" in diameter, we may easily understand how germi- 

 nation may take place as the result of an incipient decay wholly 

 unrecognizable by chemical reactions. The quantity of ammonia 

 required to feed such minute plants could not be detected by any 

 means which we possess ; and hence we might under certain 

 circumstances be led to suppose that the germination may have 

 preceded the change of the substance upon which the plants 

 grew. 



The question raised by Pasteur is one of very great import- 

 ance, because if we admit the existence of distinct ferments 

 having each a speciality of action, we must of necessity also 

 admit that the original cause of many diseases, both in plants 

 and animals, is the germination of fungi, — and perhaps also the 

 possibiUty of spontaneous generation. The latter M. Pasteur 

 appears to accept. Experience, however, shows that although the 

 spores of fungi abound everywhere, they do not succeed in 

 germinating and growing except where certain favourable con- 

 ditions exist. In all cases where fungi have been observed in 

 the animal body during life, it has been on free surfaces, such 

 as the external skin, the mucous membranes, &c. : J. Vogel, a 

 very competent authoritj', states that he knew of no undoubted 

 case of fungi having been found in the middle of the parenchyma 

 of human organs. I believe that no case has ever been observed 

 of the growth of fungi in the blood, bile, or other secretions 

 during life ; and yet there cannot be the slightest doubt that 

 their spores continually find their way into the body. As an 

 * Me'moires du Mus. d'Hist. Nat. 1840. 



