PRODUCTS, ADVENTITIOUS. 



in these productions ; carcinoma may even, 

 in predisposed persons, be formed in their 

 trails, hut not (so far as evidence goes) be 

 produced in their cavity as an evolution of 

 blastema exuded from their lining membrane. 



Miiller has recently applied the name cysto- 

 sarcoma to growths, principally composed of a 

 fibro-vascular texture, but invariably found 

 to contain solitary cysts in their substance. 

 The cysts may be solitary or compound ; the 

 solid substance, of greater or less density, has 

 an indistinctly fibrous structure, contains no 

 cells, and is of albuminous basis. This growth 

 is essentially distinct from carcinoma, but that 

 it differs genetically from sarcoma seems ques- 

 tionable. 



Secondary cysts are not spontaneously 

 generated, but form through the influence of 

 bodies foreign to the site they occupy : around 

 effused blood, after a series of modifications 

 (the apoplectic cyst), around adventitious pro- 

 ducts, extra-uterine foetuses, and bodies intro- 

 duced from without, as musket-balls, shot, 

 pins, &c. 



A sort of pseudo-cyst is sometimes produced 

 by distension and closure of small natural cavi- 

 ties, or of the excretory ducts of glands. In 

 the first class we find dilated cutaneous follicles, 

 intestinal crypts, and solitary glands ; to the 

 second class belong cysts of the lactiferous 

 and pancreatic tubes, of the labial and sub- 

 maxillary glands, some of those in the testicle, 

 and, it is commonly believed, in the kidney.* 



Fibrous and Elastic Pseudo-Tissues. Of the 

 production of white fibrous-tissue of an im- 

 perfect kind, numerous examples have been 

 referred to in the past pages, it is one of 

 the commonest of new formations. 



Less common by far is the generation of the 

 yellow fibrous element, which is distinguished 

 by resisting the action of acetic acid ; the 

 mesh-like arrangement of bifurcated fibres is 

 much rarer in the imitation new tissue than in 

 its prototype, nor does the former occur 

 (so far as we know) in masses of any size. 

 The modification of this texture which con- 

 stitutes the main element of artery is doubtless 

 produced in new vessels. 



Osseous Pseudo-Tissue. The most perfect 

 imitation of a complex natural texture is ex- 

 emplified by adventitious bone, produced for 

 the reparation of injuries (Permanent Callus). 

 It is even said that the permanent callus has 

 all the characters of true bone, a proposi- 

 tion which appears to us to require more 

 absolute proof than it has yet received. The 

 new bony shaft, produced to supply the ravages 

 of necrosis of the long bones, is a ruder 

 imitation of original bone ; it is darker in 

 colour, rough, and tuberculated on the surface, 



* Cystic productions in the kidney still require 

 investigation from the minute apparently soli- 

 tary cyst, to those clustered masses causing de- 

 struction, more or less complete, of the proper renal 

 substance. Dr. Johnson (Med. Chir. Trans, vol. 

 xxx.) adduces arguments of a novel kind to prove 

 that the simple cyst is in reality a dilated tube ; 

 Mr. Simon (eod. torn.) seeks to show that it is a 

 new development within the parenchyma. 



141 



(See 



and often much denser than the latter. 



OSTEOMA, p. 134.) 



Nervous Pseudo-Tissue. In certain of the 

 simpler varieties of neuroma the induration- 

 matter mainly forming the tumour appears to 

 contain a larger proportion of tubular fibres, 

 than would in the natural state fall to the 

 share of a portion of nerve of similar length. 

 The tissue in excess (admitting the fact to be 

 substantiated) might, however, be rather re- 

 garded as an hypertrophy than a new produc- 

 tion. 



The regeneration of voluntary nerve (ren- 

 dered probable by the experiments of Haigh- 

 ton) has been proved by those of Steinriick*, 

 Nasse, Giintherf, and Schrdn.J The tubules 

 produced in the exudation, connecting the 

 cut ends of a nerve, differ from the natural 

 ones in being more widely apart, of smaller 

 diameter, less parallel to each other, more 

 intertwined, and more mixed with cellular 

 fibrils. The time required for their produc- 

 tion varies, a month appears to be the shortest 

 period yet observed ; the length of nerve 

 which may be excised is yet unsettled. In 

 the majority of cases, even where reproduction 

 is seemingly perfect, the physiological action 

 of the injured cord remains imperfect; probably 

 because the corresponding parts of the same 

 fibres are nut, or because sensitive and motor 

 fibres are, brought into connection ; besides 

 the new tubules are not the precise physical 

 counterparts of the old, nor is their number 

 as great as in the original texture. 



Cerebral substance removed from animals is 

 replaced by a brain-like matter : the precise 

 nature of this matter (as of that appearing in 

 hernia cerebri in man) has not been examined 

 sufficiently. It seems very doubtful that 

 dynamic vesicular texture ever forms adventi- 

 tiously. 



Blood-vessel. The development of new 

 blood-vessels, though so common, is but ill 

 understood. They must obviously be pro- 

 duced from pre-existing trunks, or be evolved 

 independently. 



Viewed as productions from the old vessels, 

 they have been supposed to be mere prolonga- 

 tions of these, a notion set aside by the fact 

 that vessels do not terminate by open mouths. 

 Or, again, they have been considered the pro- 

 duce of a looping process the increased 

 impulse of the circulation towards the site of 

 vascularisation being supposed, when com- 

 bined with a relaxed state of their own tex- 

 ture, capable of elongating the old trunks into 

 loops : it seems probable that increased vas- 

 cularity may, to a limited degree, be produced 

 on this plan. Or, again, it has been conjec- 

 tured that processes, first solid, subsequently 

 hollow, spring from the sides of the original 

 vessels, an hypothesis unsupported by direct 

 evidence and deficient in plausibility. Or, 

 lastly, it has been maintained that the first step 

 in the process consists of rupture of original 



* De Nerv. Regenerat. Berol. 1838. 

 t Miiller's Archiv. Heft V. S. 405. 

 J Miiller's Archiv. 1840. 



1839. 



