INFLAMMATION AND TUMOURS. 233 



inflammation. Hence we can only admit the existence of in- 

 flammatory — and we may add, of neoplastic processes generally 

 — in those organs where the blood-corpuscles originate, viz. the 

 lymphatic glands ; on the other hand, we not only admit, but 

 most distinctly affirm, that such inflammatory action may influ- 

 ence and alter the composition of the blood itself. 



§ 199. A former attempt to define the leading characters of 

 lymphadenoid tissue led us to the conclusion that it could not 

 be better described than as a tissue in which an early phase of 

 development — a phase very nearly allied to embryonic tissue — 

 had become in a measure permanent. This circumstance must 

 be borne in mind when we see how readily the lymphadenoid 

 tissue may be induced to develope in any direction whatever, 

 when prompted by an appropriate stimulus. Should the organs 

 fi'om which the lymphatic glands derive their lymph be inflamed, 

 this may give rise to suppurative, caseous, and indurative lym- 

 phadenitis ; the specific inflammations are all reproduced in the 

 corresponding lymphatic glands ; e.g. the syphilitic gumma, the 

 mihary tubercle, the typhous product (§ 112) ; finally, almost 

 all the carcinomata implicate the nearest lymphatic glands as 

 a first step towards infecting the entire organism. Moreover, 

 the morbid product, whatever it may be, manifests itself in the 

 lymphadenoid tissue with a simplicity and completeness often 

 lacking in the primary growth ; to this rule there are but few 

 exceptions ; and hence it is that the lymphatic glands may be 

 recommended as especially adapted for the investigation of the 

 proper structure of a tumour. This however must not be taken 

 to mean that the lymphatic glands are equally favourable for the 

 study of the developmeyit of morbid growths ; on the contrary, 

 this is just the point at which our knowledge fails us most, as 

 will be cleai'ly enough seen from the following summary. 



§ 200. I. Acute lympliadenitis. The internal condition of a 

 lymphatic gland which, owing to inflammatory changes in the 

 area of distribution of its afferent lymphatics, has become mode- 

 rately swollen and tender, may be taken broadly to consist in 

 hyperasmic distension of its vessels, together with an increase in 

 the number of its contained lymph-corpuscles. Whence are these 

 corpuscles derived ? We may adopt one of three hypotheses to 

 account for the fact, and bring very weighty analogies in sup- 

 port of each in turn. For instance, we may assume a migration 



