PUTREFACTION AND FERMENTATION 483 



to him preposterous. But when the microscope is apphed to these creatures, 

 and we see that they rank in the type of their organization with spiders or 

 crabs, and that they are similarly provided with organs of reproduction, it 

 seems to us as absurd to suppose that they have arisen from a mere alteration 

 in the cheese as it would be to imagine that crabs could spring spontaneously 

 out of a piece of dead fish or other garbage upon which they prey. Yet though 

 no physiologist doubts that cheese-mites do arise from parentage, it must be 

 confessed that there is some difficulty in accounting for their almost invariable 

 occurrence in some kinds of cheese kept for a sufficient length of time. 

 Whether the eggs are transferred by the hand of the cheesemonger, or whether 

 the adult mites migrate from cheese to cheese, may be matter for curious 

 discussion. 



But though with creatures as large, comparatively speaking, as the cheese- 

 mite, it may not be very easy to explain the extensive diffusion of their ova, 

 this difficulty becomes less and less the more minute the organism. If a vessel 

 containing preserved fruit is left exposed to the air, the surface of the preserve 

 soon becomes covered with mould, and it is then found to have a 'mouldy' 

 flavour — implying alteration in its chemical constitution. The mould itself 

 has a flavour of its own, and it has developed, in part at least, at the expense 

 of the preserve. If the mould is examined microscopically, it is seen to be just 

 as distinctly a vegetable as a cabbage is, and far more abundantly provided 

 with reproductive apparatus. Supposing it to be the ordinary blue mould, 

 the blue tint is simply the colour of the fructification. This is in accordance 

 with a general law in the organic world, that so far from an}' deficiency appearing 

 in the arrangements for reproduction in the lower forms of life, so as to make 

 it difficult to account for their originating from parents, the lower the organism 

 the more lavishly is this provided for. In some animals low in the scale of 

 being we find, besides the formation of ova, a faculty of self-multiplication 

 by segmentation, or, as it is termed, fissiparous generation. F^or what purpose, 

 I venture to ask, can be this ample provision for reproduction of the lowest 

 species by parentage, if they can spring spontaneously out of the materials 

 in which they grow ? 



Now, in the case of the blue mould, the sporules, besides being produced 

 in incalculable multitudes, arc of extreme minuteness, and constitute a very 

 fine dust, which cannot fail to be wafted and extensiveh- diffused through the 

 air. If a rav of sunlight were to shoot through this room, wo should see the 

 sunbeam peopled with motes. But the particles of dust which are rendered 

 visible to the naked eye by being so illuminated, are gross indeed compared 

 with the sporules of such a fungus. Some of them are complicated organic 



