DISEASES OF THE BLOOD. 121 



whence probably the frequency of invasion of lymphatic 

 glands ; or by continuity and contiguity of structure. 

 The systemic symptoms are not acute enough to constitute 

 fever^ producing rather a cachexia, or unhealthy state of 

 the constitution. Determination of whether any local can- 

 cerous deposit is primary or secondary is of importance 

 from a surgical point of view. When primary, a growth 

 may be excised with some chance of success in permanent 

 removal of the disease. In secondary cases the system is 

 hopelessly invaded ; and it will be found that any injury, 

 however slight, is almost sure to take on unhealthy action. 

 Local treatment except by excision has not proved satis- 

 factory, probably in consequence of the difficulty of access 

 to all the diseased parts. Acetic acid has been recommended 

 as causing alterations in the cells, of which, the growth is 

 composed. Its value is doubtful. When the morbid matter 

 is removed by excision care must taken that not the smallest 

 diseased part remains as a centre for renewed growth. 



Scrofula, Tuberculosis, is frequent in cattle, extremely 

 serious in its effects, and has interesting relations with 

 human disorders. It is a constitutional disease, specific, 

 and infective. It seems to increase in frequency pari 

 passu with improvement of the breed, and thus short- 

 horns, especially good milkers, are most predisposed to the 

 disorder. That it is a blood disease is proved by the fact that 

 it very frequently affects many organs of the body, that its 

 local manifestations are varied in position, and that its 

 presence is generally denoted by a cachexia, an ill-disposed 

 habit of the body, which is termed the scrofulous diathesis. 

 It is undoubtedly hereditary, and therefore manifests 

 its presence most forcibly after " breeding in and in.^' 



Scrofula is the disease of the system of which Tubercle 

 is the local manifestation. That we may be in a position 

 to appreciate the interesting questions raised in the study 

 of this disorder, we must first note the forms which it 

 assumes in the ox. 



Phthisis Pulmonalis is pulmonary scrofula. It is a 

 chronic disorder in which tubercles occur in the lungs, and 

 give rise to a slow local inflammation by the irritation 



