398 Lecture on the Parasitic Fungi of the British Farm. 



VII. I will lastly touch on the facts now established relative 

 to the fungi attacking animal tissues, which are very surprising-. 

 Sapy meat has always a fungus something analogous to what is 

 called the yeast fungus. T\ns fungus is a mass of molecules, pro- 

 bably an early state of the same that is called the Vinegar Plant, 

 the last stage of which has been stated to be a penicillium. 

 What are called sclerotia, from aycXnpos, hard, appears in animal 

 matter under particular circumstances ; but these are only states 

 of other fungi, for even agarics have been known to spring 

 from them. The fungus of the West Indian wasp, of the 

 caterpillar of New Zealand, and the muscardine of the silk- 

 worm, are all well-known examples of fungi attacking living 

 animals. The last is easily propagated by inoculating healthy 

 caterpillars, which I mention to show that a fungal disease may 

 be conveyed from one animal to another in a state of health. I 

 believe a more accurate knowledge of such facts will be ultimately 

 of great use in investigating certain diseases prevalent among 

 animals of the farm and hitherto inexplicable. Sclerotia have been 

 found in bad fractures, but they are not parasites ; true parasitic 

 animal fungi grow only on the skin or mucous membranes. M. 

 Robin published in 1847 a most curious account of the vegetable 

 matters growing on living mammalia, which he classes into two 

 divisions — those of the skin, and those of the mucous membranes. 

 The mucous membranes of the digestive canal and of the lungs 

 are subject to their attacks ; nor is the stomach free. All herbi- 

 vorous animals are liable to moulds in the digestive canal, very 

 like the yeast fungus, but larger ; yet it is confined to them, and 

 never found in carnivora, birds, or reptiles. A penicillium of 

 birds is tolerably well known; and pheasants, fowls, and pigeons 

 are the prey occasionally of a mould as yet imperfectly described. 

 An aspergill is found in eggs ; and that found in the air-cells of 

 the lungs of the eider-duck has been often noticed. Parasitic 

 animal fungi yield, it is said, to sulphuric acid, whence a hint 

 may be obtained as to remedy ; but I wish to speak with due 

 caution on these novel investigations. Attempts have been made 

 to inoculate dead animals with these fungi; they have entirely 

 failed ; the life of the animal is essential to their growth, the con- 

 ditions of which seem generally to be imperfect states of respira- 

 tion or nutrition, or irregularity. There seems to be a moment 

 when the powers of assimilation flag, and then the fungi step in 

 and appropriate the nourishment designed for the system. It 

 may be the same with apparently healthy plants. We may here 

 have the first ward of the key to many a hidden secret as to the 

 ailments of the animals of the British farm. 



VIII. I have now completed my humble attempt to give a. 



