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sloughing of the extremities about the region of the fetlocks. A curious 

 fungus, which is known as actinomyces, or rayed fungus (fig. 477), attacks 

 certain grains and grasses, especially in river valleys, which, on being 

 consumed, sets up centres of disease in different parts of the animals 

 which feed on the infested plants. Sometimes it gets an entrance to the 

 alveolar cavities by the side of a loose or decayed tooth, penetrating into 

 the sinuses of the head and the cellular structure of the bones, causing 

 enormous swellings, giving rise to the disease which is known in America 

 as " Lumpy jaw". In other situations it causes large tumours in the 

 neighbourhood of the throat, in the stomach, 

 and also in the intestines. 



Besides the vegetable parasitic fungi 

 which attack food plants there are numerous 

 animal parasites, and animals supplied with 

 food so attacked suffer in various ways; in 

 the first place from the damage done to the 

 fodder by the ravages of £he parasites, and 

 in the second place from the direct attack 

 of the parasites themselves, some of which 

 produce irritation of the skin. An unfortu- 

 nate circumstance connected with the effects 

 of damaged food invaded by animal or vege- 

 table parasites is the difficulty of connecting 

 the disease of the animal with the disease 

 of the plant. The tendency undoubtedly is 

 to exonerate the food from suspicion, even 

 to ignore it altogether as a possible cause 

 of disease, until a considerable fatality has 

 forced the owner to conclude that some 

 common cause must be at work to produce it, and even then it frequently 

 occurs that the investigation which is made is directed into the wrong 

 channel by the history of the case which is presented to the investigator, 

 who is very likely to be informed that exactly the same articles of food have 

 been, and are still being, supplied to other animals on the same premises, 

 which have not suffered in consequence. This is a source of error which 

 is particularly likely to occur when the food wdiich is suspected is some 

 kind of cake. It is quite possible that a cake contaminated with mould 

 may be part of a lot which was supplied at the same time as the cake 

 on which other animals are feeding with impunity, and that the animals 

 which are poisoned are the only ones which have eaten the fungus-in- 

 fected food. The investigator, therefore, should not be satisfied until 



Fig. 477. — Actinomyces Bovis 



1, The fungus on cow's tongue; 2, Cell 

 or group of cells with actinomyces ; 3, 

 Clubbed filaments and centre filaments 

 of the fungus; 4, Filaments from the 

 centre enlarged. 



