ACTINOMYCOSIS. 431 



(V.) The skin and subcutaneous tissues are a favourite seat of this 

 disease, producing the so-called wens or clyers so commonly seen in the 

 fen country. A wen is first recognised as a small tumour, the size 

 of a marble or walnut, which increases in size sometimes with great 

 rapidity, and breaks down and discharges its muco-purulent contents 

 through the inflamed and ulcerated skin ; or it may go on increasing, 

 and form a large compact growth, the size of a child's head. These 

 growths when excised, hardened, and cut, have a characteristic 

 honeycombed appearance, produced by the interlacing bands of 

 fibrous tissue, which form a spongy structure, from the interstices 

 of which the fungus tufts and thick yellowish pus have for the 

 most part dropped out. 



Actinomyces Hominis. Careful examination of pus from 

 a, case of actinomycosis in man will reveal to the naked eye little 

 yellowish-white or yellow bodies, which a casual observer might 

 mistake for grains of iodoform. On collecting some of the discharge 

 in a test-tube, and holding it between the light and the eye, the tufts 

 of fungi appeared as brownish or greenish-brown grains, embedded 

 in a muco-purulent matrix. 



On spreading some of the discharge on a glass slip, the largest 

 tufts of the fungus are found to be about the size of a pin's head. 

 They have a distinctly sulphur- yellow colour by reflected light, but 

 appear of a yellowish or greenish- brown tint by transmitted light. 

 With a sewing needle, or a platinum wire flattened at the end into 

 a miniature spatula, the grains can be readily picked out of the 

 discharge, or taken off the dressing, transferred to a clean slide, and 

 gently covered with a cover-glass. Examined with an inch objective, 

 they have the appearance of more or less spheroidal masses of a 

 pale greenish -yellow colour. On removing the preparation from the 

 microscope, and gently pressing down the cover-glass with the finger, 

 the grains flatten out like specks of tallow ; and on again examining 

 with the same power they are found to have fallen apart into a 

 number of irregular and sometimes wedge-shaped fragments of a 

 faintly brown colour, affording a characteristic appearance. By 

 preparing another specimen, and covering it with a cover-glass 

 without completely flattening out the grains, the spherical, oblong 

 and reniform masses of which the tufts are composed can be 

 recognised with a J- in. objective as rosettes of clubs. By examining 

 the peripheral part of a rosette with a Yj-in., and especially after 

 pressing the grains into a thin layer, with or without the addition 

 of a drop of glycerine, the characteristic clubs are most readily 

 demonstrated, and the most varied shapes observed by carefully 



