ACTINOMYCOSIS. 2 55 



discharged from the " cold abscesses" which are formed in the 

 pig or in the human subject, similar small yellow points 

 (which appear as green or greenish yellow grains, even 

 when examined with the naked eye) may be found on 

 examination under the microscope. The pus discharged 

 from these abscesses has an exceedingly characteristic appear- 

 ance ; it is usually yellow or brownish yellow in colour, 

 is extremely granular, of a peculiar slimy consistence, 

 and contains the green points that may be said to be 

 specially diagnostic of the actinomycotic condition. The 

 small green points when taken from the cow are very 

 frequently somewhat gritty, this being due apparently to the 

 deposition of particles of lime in the core ; but the particles 

 that come from the pus in the human subject are usually 

 soft and tallow-like, so that they can be readily flattened out 

 between two cover glasses. The appearance of the actino- 

 myces or " ray fungus ' in cattle, as first described, was 

 so exceedingly characteristic that it was thought it could 

 not be mistaken for anything else, and the corresponding 

 condition in the human subject was for some time over- 

 looked, simply because the same typical appearances were 

 not always developed ; and it was only after some time that, 

 transition stages being found, first in cattle and then in the 

 human subject, the real nature of this fungus was thoroughly 

 understood. 



On examination of the fungus under a high magnifying 

 power, when the sections have been properly stained, the 

 organism is found to be like the capitulum of a daisy, the 

 sterile flowers in the centre corresponding to the club- 

 shaped rays, and if we conceive of two of these heads of 

 flowers as placed base to base, or stalk to stalk, we may 

 obtain an idea of the appearance of the ray fungus as a whole ; 

 the organism in sections of course having the appearance 

 of sections through the little ball formed by the two heads. 

 The clubs, however, are not all simple, but in some cases 

 branch, sometimes dichotomously, sometimes irregularly, 

 compound clubs being thus formed. 



In a tumour examined by Professor M'Fadyean, the transi- 

 tion stages between the forms sometimes found in the human 

 subject, and those most frequently seen in cattle, are met with ; 

 and as I have had the privilege of seeing Professor M'Fadyean's 

 specimens I shall follow pretty closely his descriptions, as 



