580 MICROBIOLOGY OF THE DISEASES OF MAN AND ANIMALS. 



the effort to use other fungi as insect-destroyers. The conditions which 

 make possible their development in epidemic form only occur occasionally. 

 These conditions in themselves are, as a rule, very unfavorable to insects. 

 Under other climatic conditions, these diseases appear only as isolated 

 cases, negligible in their effect upon the insect population, no matter 

 how carefully the inoculating material is spread by man. 



ACTINOMYCOSIS.* 



Actinomyces bovis.^ 



This is a rather common disease of domestic animals, especially cattle. 

 It prevails in Europe, North and South America, and is known by various 

 names as lumpy jaw and wooden tongue. Cattle are most commonly 

 affected, but humans, horses, sheep, and dogs are susceptible. Actino- 

 myces produces a local disease which never spreads widely or rapidly. 



Actinomycosis is to be considered as an infectious disease which 

 spreads by inoculation. 



The disease produced by this microorganism usually runs a chronic 

 course and is distinguished especially by enlargement of affected parts, 

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

 most constant and conspicuous characteristics. Head parts, including 

 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 little risk to human health from actinomycosis 

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



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

 complicated group of microorganisms higher than bacteria and are 



* Prepared by M. H. Reynolds. 



t Actinomyces bovis has been classified by Frost (page 55) as a species of bacteria, 

 but, because of many features, it is here inserted with the organisms strictly belonging to 

 molds and yeasts. Ed. 



