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. CoralHn 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 vary 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 sUde the grains readily 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 yeUowish-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 wiU 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 



