INFECTIOUS DISEASES OP CATTLE. 431 



Although actinomycotic tumors on cattle had been the object of 

 study for many years, it was not until 1877 that the constant presence 

 of actinomyces was pointed out by Bollinger, of Munich, and since 

 that time considered the cause. This fungus has been observed in 

 these tumors as early as 1860 by Rivolta, and by others subsequently, 

 without having been suspected as causing them. 



Since Bollinger's publication a large amount of work has been done, 

 many observations made, and many hitherto obscure disease proc- 

 esses brought into relation with this fungus. Furthermore, a similar 

 disease in man was first definitely shown to be associated with the 

 same fungus in 1878 by Israel, and in the following year Ponfick 

 pointed out that the disease described by Bollinger in animals and 

 that found by Israel in man were due to the same cause; that is, that 

 the fungi described by these observers were one and the same. 



The tumors and abscesses wherever they may be situated are all found 

 to be the same in origin by the presence of the aetinomyces fungus. 

 When they are incised, a very close scrutiny with the naked eye, or at 

 most a hand lens, will*reveal the presence of minute grains which vary 

 from a pale-yellow to a sulphur-yellow color. They may be very abun- 

 dant or so few as to be overlooked. They are embedded in the soft 

 tissue composing the tumor or in the pus of the abscess. With a needle 

 they are easily lifted out from the tissue, and then they appear as 

 roundish masses about one-half millimeter (-^ inch) in diameter. To 

 anyone familiar with the use of a microscope the recognition of these 

 grains or particles without any previous preparation is a compara- 

 tively easy task. 



When examined in the fresh condition under a microscope magnify- 

 ing up to 250 diameters the general structure is made out without 

 much difficulty. These grains consist of collections of minute round- 

 ish masses. Their outer surface is made up of club-shaped bodies all 

 radiating from the center of the mass (see PL XLI, fig. 2), some- 

 what like a rosette. If the fungus is crushed, the interior is found 

 made up of bundles of very fine filaments, which are probably con- 

 tinuous into the club-shaped bodies. The addition of a dilute solu- 

 tion of caustic soda or potash greatly aids the examination, since it 

 removes the layer of cells adhering to the fungus, which obscures the 

 structure. Now and then these grains are found to be in a calcified 

 condition. The exterior is incrusted in lime salts, which are dis- 

 solved by adding some weak dilute acid, like acetic acid. Only by 

 this procedure can the fungus be definitely recognized when in a mum- 

 mified condition. 



These are the bodies whose presence causes sufficient irritation in 

 the tissues into which they find their way to set up inflammatory 

 growths. These growths increase as the fungus continues to multiply 

 until they reach enormous dimensions, if the affected animal is per- 

 mitted to live long enough. The true nature of this parasite is not 



