434 INFECTIVE DISEASES. 



grains. The grains are picked out of the pus and transferred to 

 watch-glasses containing strong potash, xylol, and benzol. If 

 returned to a slide and covered with a cover-glass, the clubs are 

 found unaltered. Water or weak potash washes away the clubs, 

 and the filaments become easily distinguished ; ether and strong 

 acids have no effect upon them. Oorallin soda, Hanstein's violet, 

 and iodine zinc-chloride fail to give any particular reaction. 

 Hoffman's blue stains the clubs, but without bringing out any 

 structural details which could not be observed in the unstained 

 specimens. 



Actinomyces bovis. — The fungus in cattle may in the same 

 way be detected with the naked eye in the muco-purulent discharge, 

 ■or in a scraping from the cut surface of a growth. The tufts of the 

 fungus vai'y in size under different circumstances, from that of a grain 

 of fine sand to that of a pin's head. If the pus or scraping be spread 

 out on a slide and examined against a dark background, the grains 

 appear to be white or yellowish-white in colour ; but if examined by 

 transmitted light, they appear distinctly brownish. On pressing the 

 ■cover-glass on the slide the grains readil}^ flatten out, being of a 

 soft, tallowy consistency ; or in the process of gently pressing the 

 cover-glass on the slide with slight lateral movement, a distinct 

 gritty sensation is transmitted to the finger, owing to the presence 

 ■of calcareous matter. On examination with a low power the 

 fungus will be recognised in the form of irregular patches scattered 

 over the field, which might readily be regarded as collections of- 

 granular debris of a brownish or yellowish-brown colour, but on 

 careful examination they are observed to have a more or less 

 characteristic appearance. On examining with a higher power, 

 spherical, ovoid, or reniform bodies are to be seen, which are 

 ■either typical rosettes of clubs or granular masses, with here 

 and there a club-shaped body at the periphery. Pus cells, round 

 cells, fat granules, and minute spherical bodies may also be 

 ■distinguished. If the grains consist of typical rosettes, and be 

 merely covered with the cover-glass, and examined without being 

 flattened out between the cover-glass and the slide, they will recall 

 to mind, on focussing alternately the centre and the periphery, 

 the appearance of the capitulum of a composite flower. The central 

 portion appears to consist of spherical forms ; these are the ex- 

 tremities of the component elements, and as we focus the edge of 

 the rosette these elements are seen laterally, and their characteristic 

 club-form is readily distinguished. The central portion may be 

 flattened against the cover-glass, and as the individual clubs vary 



