728 MICROBIOLOGY OF DISEASES OF MAN AND DOMESTIC ANIMALS 



by hardening of the tongue, and by suppuration. The latter is one of 

 the most constant and conspicuous characteristics. Head parts, in- 

 cluding the facial bones, are commonly affected; lungs and various other 

 internal organs and even the vertebrae may be involved. 



The extent of injury done by this fungus depends on the location 

 and size of the involved area. Usually the most conspicuous injury is 

 impaired nutrition. 



There is probably but Uttle risk to human health from actinomycosis 

 in cattle as parts of the carcass most commonly affected are not eaten 



Fig. 153.— Actinomyces hovis. The ray-fungus from cow. (Diagrammatic.) 



{After Williams.) 



and edible parts are usually cooked. It is generally considered that 

 sound portions of carcasses which do not show generalized disease are 

 fit for human food purposes. 



There are apparently several varieties of Actinomyces all of which 

 are recognized for the present as Actinomyces bovis. 



The varieties of Actinomyces are to be regarded as members of a very 

 complicated group of microorganisms higher than bacteria and are 

 generally spoken of as fungi. Actinomyces bovis is commonly known 

 as the ray-fungus (Fig. 1 53 ) . Its relation to the disease of actinomycosis 

 is probably specific but it is frequently aided by pus producing bacteria. 



It is believed that the Actinomyces vegetate on various grasses, 

 especially wild barley, and that infection occurs by inoculation with the 

 awns and barbs of such grasses through the mucou^ membrane of the 

 mouth or other portions of the aUmentary tract. 



