196 PHYSIC 



gradually disintegrates, and, with the aid of a cough, 

 succeeds in expelling, leaving a cavity behind, which in 

 time is joined by other such cavities, due to similar patho- 

 logical processes, and converted into the fully developed 

 " tubercular pulmonary cavity," such as is met with in the 

 advanced or concluding stage of the disease. 



This pathological sequence of events is generally slow, 

 but it must be remembered that it is not necessarily always 

 so, because cases are sometimes met with in which the 

 whole phenomena are so hurried, and the progress so rapid, 

 that from the first a fatal issue is inevitable, the assistance 

 of hygiene and therapeutics being alike futile. 



In many of the slowly progressive cases, however, the 

 phenomena of metastasis are to be observed ; thus when 

 the peculiar cough of pulmonary phthisis becomes estab- 

 lished, and the disintegrative changes, due to advancing 

 growth of the bacillary organisms of the miliary tubercles 

 and the consequent breaking down of contiguous lung 

 textures begins, we observe, and may trace, the invasion 

 of the central nervous system, by zymotic growth of the 

 specific bacillus, along the pneumo-gastric terminal fibres, 

 and their connected trunks and inter-neurilemmar spaces, 

 into the cerebro-spinal cavity. Having reached this 

 cavity, and overrun its contained lymph and nervine 

 elements, the bacillary organisms are conveyed far and 

 wide by the distributive agency of that lymph, as it is 

 continuously excreted, along the inter-neurilemmar spaces 

 of the entire cerebro-spinal nervature, sensory as well as 

 motor, hence the secondary invasion of the skin and the 

 joints, as well as the textures and organs more directly 

 innervated by the sympathetic nervous system, by way of 

 its rami communicantes. 



Moreover, there are cases of tuberculosis or tabes, in 

 children especially, where the invasion of the intestinal 

 canal is effected primarily by imbibition with the food or 

 drink, and secondarily from the lungs by the expectorated 

 tubercle, laden with pulmonary detritus, which conveys the 

 bacillus along the secretory paths by which the chyle is 

 conveyed into the blood streams, leaving en route in the 

 mesenteric glands sufficient organisms to produce, through 

 destructive changes and mechanical blockage, a more or 



