406 APPLICATION OF METHODS OF BACTERIOLOGY 



a pin-point to that of a hempseed, and, as a rule, are, in 

 this stage, the result of the fusion of two or more still smaller 

 foci. Though the two terms "miliary" and "conglomerate" 

 are employed for the description of the macroscopic appear- 

 ances of these nodules, yet it is very rarely that any condition 

 other than that due to the fusion of several of these minute 

 foci can be detected by the naked eye. 



The miliary tubercles are of a pale gray color, with a 

 white centre, are slightly elevated above the surface of the 

 tissue in which they are located, and, as stated, vary con- 

 siderably in dimensions, usually appearing as points which 

 range in size from that of a pin-point to that of a pin-head. 

 They are not only located upon the surface of the organs, 

 but are distributed through the depths of the tissues. To 

 the touch they sometimes present nothing characteristic, 

 but when closely packed together in large numbers they 

 usually give a mealy or sandy sensation to the hand 

 passed over them. Stained sections of miliary tubercles 

 present a distinctly characteristic appearance, and the dis- 

 ease may be recognized by these histological changes alone, 

 though the crucial test in the diagnosis is the demonstra- 

 tion of tubercle bacilli within the nodules. 



Microscopic Appearance of Miliary Tubercles. — ^A miliary 

 tubercule under a low magnifying power of the microscope 

 presents somewhat the following appearance: there is a 

 central pale area, evidently composed of necrotic tissue 

 because of its incapacity for taking up the nuclear stains 

 commonly employed. Scattered through this necrotic area 

 may be seen granular masses irregular in size and shape; 

 they take up the stains employed and are evidently frag- 

 ments of cell-nuclei in course of destruction. Throughout 

 the necrotic area may be seen irregular lines, bands, or 



