434 DISEASES OF CATTLE. 



the lung tissue could be recognized, although even there it had been 

 largely converted into very dense, whitish, connective tissue inclosing 

 the fungoid growth. In the other case the external form of the lung 

 and the shape and outline of the lobules were preserved, but the lung 

 tissue itself was not recognizable as such. In the case first mentioned 

 the changes were still less marked, and actinomycosis would not have 

 been suspected by a simple inspection. These few illustrations suffice 

 to show that actinomycosis of the lungs may appear under quite dif- 

 ferent forms, and that the nature of the disease can be accurately 

 determined only by finding the fungus itself. Rarely actinomycosis 

 attacks the body externally in places other than th9 head and neck. 

 Crookshank describes the case of a bull in which the flank was 

 attacked and subsequently the scrotum became diseased. A large 

 portion of the skin of the flank was destroyed and covered with a 

 leathery crust. When this was pulled away the pus beneath it showed 

 the actinomyces grains to the naked eye. 



Actinomycosis may also involve the udder, the spermatic cord of 

 castrated animals, vagina, and, when it becomes generalized, the brain, 

 liver, spleen, and muscular tissue. 



Actinomycosis may in some cases be confounded with tuberculosis. 

 The diagnosis does not offer any difficulties, since the presence of the 

 actinomyces fungus at once removes any existing doubts. As has 

 already been intimated, these grains, simulating sulphur balls, are 

 visible to the naked eye, and their nature is readily determined with 

 the aid of a microscope. 



The course of the disease is quite slow. As the tumors grow they 

 may interfere with the natural functions of the body. According to 

 their situation, mastication, rumination, or breathing may be inter- 

 fered with, and in this way the animal may become emaciated. Acti- 

 nomycosis of the jawbones leads to destruction of the teeth and 

 impedes the movements necessary to chewing the food. Similarly, 

 when the disease attacks the soft parts of the head obstructions may 

 arise in the mouth by an inward growth of the tumor. If tumors 

 exist in the pharynx they may partially obstruct the movements 

 necessary to breathing, or close the air passages and cause partial 

 suffocation. Actinomycosis of the tongue, in interfering with the 

 many and varied movements of this important organ, is also a serious 

 matter. There is no reason to suppose that the localized disease 

 interferes with the general health in any other way than indirectly 

 until internal organs, such as the lungs, become involved. 



A very small proportion of the cases may recover spontaneously, 

 the tumors being encysted or undergoing calcification. In most cases 

 the disease yields readily to proper treatment, and about 75 per cent 

 of the affected animals may bo cured. 



Prevention. — The question as to how and where animals take this 

 disease is one concerning which we are still in the stage of conjecture, 



