ACUTE MILIARY TUBERCULOSIS. 349 



sages. It might be assumed that where each organism is 

 deposited from the blood there results the accumulation of 

 epithelioid and lymphoid cells, with possibly a giant-cell in 

 their centre, which constitutes the typically histological 

 tubercle ; and that the " system " of such histological tubercles, 

 of which even the smallest gray miliary tubercle visible to the 

 naked eye is formed, results from the presence of as many 

 organisms. Secondarily are noted the exudations into the 

 surrounding air-spaces. The conditions which hold in the 

 lungs differ from those in other organs of the body on account 

 of the accessibility of the former not only to the tubercle 

 bacilli in larger numbers, which is regarded as an explanation 

 of the greater prominence of inflammatory exudations, but 

 also to streptococci and other secondarily infecting organisms, 

 which play a most important part in pulmonary tuberculosis. 



Acute Miliary Tuberculosis. 



Acute miliary tuberculosis occurs usually as part of a gene- 

 ral miliary tuberculosis, which not infrequently results from 

 the rupture of some tubercular focus such as a caseous 

 lymph-gland into a bloodvessel ; or follows operations upon 

 tubercular joints or bones. Clinically the disease has always 

 had a peculiar interest on account of its resemblance to 

 typhoid fever at certain stages. 



The lungs are congested and studded throughout with small 

 grayish, gelatinous-looking nodules about the size of millet 

 seeds or small shot; at first they may be so small and trans- 

 lucent as to be scarcely visible to the naked eye, though 

 finally becoming quite large, especially in the lungs of chil- 

 dren. They may be widely separated or so closely set as to 

 solidify the whole lung. Some may be yellowish from ad- 

 vancing caseation. Microscopically it is noted that these 

 nodules are situated in the intorlobular or interalveolar septa, 

 and are composed of several histological tubercles (Fig. 154). 

 In these acute processes giant-cells are not often seen, the 

 centre and often the entire tubercle being caseous. The sur- 

 rounding air-spaces may be more or less completely filled 

 with inflammatory exudates, and the interalveolar septa con- 

 siderably thickened. 



