DISEASES OF THE OX AND SHEEP. 273 



recovery. In sheep we ourselves have not met with any cases. 

 Doubtless, sheep may become affected ; but, fortunately, it is not 

 common among them. The goat is sometimes affected. 



Of the symptoms and methods of treatment of actinomycosis 

 we now propose to treat ; but before concluding we ought to 

 point out emphatically the inadvisability of employing mouldy 

 food for horses or cattle, for it is so commonly a source of 

 disease. Mouldy oats, mouldy hay and straw are equally bad 

 for cattle or horses, and should not be given as food. 



Of the many natural groups of the vegetable kingdom pro- 

 bably no one is less generally studied by agriculturists than 

 that of the fungi, to which the moulds or hyphomycetes, of 

 which we spoke above, belong. There is another mould 

 which we might have mentioned, it being of great interest 

 as the cause of salmon disease. We allude to the saproleffnia, a 

 fungus which consists of colourless tubular filaments forming 

 gelatinous masses on living or dead animal and vegetable matter 

 existing in fresh water. 



Our readers are aware that no fungus contains any chlorophyll, 

 the green colouring matter which gives other vegetals the power 

 of dissociating the carbonic acid gas of the air, so as to retain 

 the carbon and liberate the oxygen. This, green plants are 

 enabled to do in the presence of sunlight; but fungi cannot 

 Hve without organic matter, living or dead, unless certain 

 complex organic compounds, such as tartrate of ammonium, be 

 supplied. The saprolegnia grows on the skin of living fish, and 

 thus sets up serious mischief, just as Tinea tonsurans grows on 

 the hair of man, or Tinea circinata on the human skin. 



It is to Professor Huxley that the honour of first demonstrating 

 this fungus as the cause of salmon disease is due. 



The filaments of this mould penetrate the scales of the skin 

 in the affected areas of the salmon, and then they grow inward, 

 boring their way through the superficial layers of the skin. 

 The stem portion of the parasite is situated in the scarf-skin or 

 epidermis, and the root portion in the deeper layers ; each of 

 the filaments then elongates and branches out. The free ends 

 of the stem filaments rise above the surface of the skin, and 

 become converted into flask-shaped zoosporangia^ or little 

 bulbar endings containing in their interior numbers of oval 

 spores or zoospores possessed of motile power. This power they 



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