268 BACTERIOLOGY. 



rarely that any condition other than that due to the 

 fusion together 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 exist, 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 noth- 

 ing characteristic, but may frequently, when closely 

 packed together in large numbers, give a mealy or 

 sandy sensation to the fingers. Stained sections of these 

 miliary tubercles present an entirely characteristic ap- 

 pearance, and the disease may be diagnosticated by these 

 histological changes alone, though the crucial test in 

 the diagnosis is the finding of tubercle bacilli in these 

 nodules. 



MICROSCOPIC APPEARANCE OF MILIARY TUBER- 

 CLES. The simple miliary tubercles under the low mag- 

 nifying power of the microscope present somewhat the 

 following appearance : There is a central pale area, evi- 

 dently composed of necrotic tissue because of its inca- 

 pacity for taking up the nuclear stains commonly 

 employed. Scattered here and there through this ne- 

 crotic area may be seen granular masses irregular in size 

 and shape; they take up the stains employed, and are 

 evidently the fragments of cell-nuclei in the course of de- 

 struction. Through the necrotic area may here and there 

 be seen irregular lines, bands, or ridges, the remains of 

 tissues not yet completely destroyed by the necrotic pro- 

 cess. Around the periphery of this area may sometimes 



