INFECTIOUS DISEASES OF CATTLE. 409 



ACTINOMYCOSIS. 

 (Plates xxxix to XLI, inclusive.) 



Actinomycosis, also known as lump-jaw, big-jaw, etc., is a local dis- 

 ease due to the formation of peculiar tumors in various regions of the 

 body, more particularly the head. In these tumors a certain fungus 

 (actinoinyces) is always present and regarded as the cause of the disease 

 process. 



Although these tumors on cattle had been the object of study for 

 many years, it was not until 1877 that the constant presence of actino- 

 myces was pointed out by Bollinger, of Munich, and since that time 

 considered the cause. This fungus had been observed in these tumors 

 as early as 18G3 by Rivolta, and by others subsequently, without having 

 been suspected as causing them. 



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

 many observations made, and many hitherto obscure disease proc- 

 * 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 l>e the same in origin by the presence of the actinomyces 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 lew 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 comparatively 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 roundish 

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

 ating from the center of the mass (see Fig. 2 of Plate xxxix). somewhat 

 like a rosette. If the fungus be crushed the interior is found made up 

 of bundles of very fine filaments, which are probably continuous into 

 the club-shai>ed bodies. The addition of a dilute solution 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 

 < \t-rior is incnisted in lime salts, which are dissolved by adding .some 

 \vcak dilute acid like acetic acid. Only by this procedure can the fun- 

 gus be definitely recognized when in a mummified condition. 



