ACTINOMYCOSIS. 431 



(V.) The skin and subcuta/neous tissues are a favourite seat of this 

 disease, producing the so-called wens or dyers 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 bi-own 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, Y^-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 



