HO 



PRODUCTS, ADVENTITIOUS. 



cartilaginous. Such products are most com- 

 monly composed of dense fibrous substance, 

 or induration-matter, as in the instance of 

 so called loose cartilages of joints.* 



Adventitious cartilage is either of the em- 

 bryonic or adult type : the former has already 

 been described under the name of enchon- 

 droma. Cartilage of adult type, certainly, 

 sometimes forms the matrix in which adventi- 

 tious bone originates ; this we have seen 

 beautifully exemplified in spicular osteophytes. 

 Analogy would lead to the admission that a 

 cartilaginous stage should always precede 

 bone-production ; yet not only is proof of the 

 constancy of this stage wanting, but we have 

 looked in vain for its traces in many specimens 

 of adventitious bone. In a very few prepar- 

 ations of that rare variety of false-joint in 

 which a pseudo-synovial membrane is pro- 

 duced, the bony surfaces (whether from frac- 

 ture or dislocation) have exhibited a cartila- 

 ginous look in patch-work ; but we have not 

 had an opportunity of submitting such a speci- 

 men to microscopical examination. Of the 

 appearance of cartilage in various Growths 

 enough has already been said. 



Nor is the production of cartilage for 

 reparative purposes more easy. A fractured 

 cartilage unites by dense fibrous tissue, or by 

 bony substance. 



SIMPLE VASCULAR TISSUES. 



Cellular Tissue. Cellular pseudo-tissue is 

 one of the most common of adventitious for- 

 mations, composed of associated white fibrous 

 and yellow fibrous (elastic) fibrils. But 

 rarely does it possess the character of the 

 natural texture in perfection ; the distinction 

 of its component filaments is less clear, the 

 fasciculation of these less regular than in the 

 typical structure. A more or less successful 

 attempt at its production is made in all cases, 

 where induration-matter forms, the highest 

 degree of perfection seems to be attained in 

 old adhesions of serous membranes. A lapse 

 of many months is necessary, however, to 

 mould the new structure into its most perfect 

 attainable form ; while on the other hand, a 

 period of seven days (as we have seen in a fatal 

 case of pleurisy) will suffice for the production 

 of an imperfect tissue of this class. 



Schwannt found that embryonic cellular 

 tissue yields no glutin ; the same fact has 

 been ascertained by SimonJ in respect of the 

 adventitious cellular tissue of condylomata, - 

 by Gueterbock, in respect of that of granula- 

 tions. The latter observer found pyin in 

 the water in which the granulation-substance 

 had been boiled. At an early period of for- 

 mation fibrin is found in association with the 

 principle (tritoxide of protein ?) to which the 

 name of pyin has been given ; eventually glu- 



* We should be unwilling to affirm that these 

 bodies are never truly cartilaginous ; but we have 

 examined a considerable number without disco- 

 vering the chemical or textural qualities of that 

 tissue. 



t Untersuchungen, S. 136. 



j Miiller's Archiv, 1839. P. 26. 



tin is yielded on ebullition, but it may be 

 doubted whether the chemical constitution of 

 the new, is ever precisely the same as that of 

 the imitated texture. 



Serous Tissue. A single layer of polygonal 

 pavement epithelium, beneath this a basement 

 membrane of singular tenuity, and yet beneath 

 this a stratum of cellular tissue, constitute a 

 serous membrane. This structure is essen- 

 tially disposed to form shut sacs, and produce 

 and retain a certain secretion. So far we have 

 a texture which is often generated adventiti- 

 ously ; but if, as is now admitted, natural 

 serous tissue is supplied in its proper sub- 

 stance with nerves*, it becomes a complex 

 structure, of which a perfect adventitious copy 

 is never generated. 



Anew serous sac may be produced (a) by 

 modification of natural structure, with addi- 

 tion of a new element ; or (b) be completely 

 adventitious. 



(a) In this class appear those well known 

 cases in which pressure, with or without fric- 

 tion, causes condensation of cellular tissue 

 with production of epithelium, the latter form- 

 ing a lining for a sac of the former. So are 

 produced new supernumerary bursae about the 

 knees, the shoulders of porters, between the 

 skin and bone of stumps, between the skin and 

 spinous processes in spinal curvature, whether 

 primary or from caries, &c. 



(/;) Purely adventitious serous tissue is 

 either (a) laminar or (b) saccular. 



(a) By the laminar variety, we understand 

 those strata of pseudo- serous tissue which 

 invest false membranes in serous cavities. 



(b) The saccular variety comprehends cysts, 

 primary and secondary. Primary cysts are 

 spontaneously evolved, are capable of indefi- 

 nite increase in number and size, through some 

 intrinsic force, constitute in themselves the 

 disease where they exist, form the material 

 they contain, are closed on all sides, lined with 

 epithelium, and simple or compound. 



Simple cysts occur singly or in clusters, 

 and may appear in almost every region of the 

 body ; their walls are of variable thickness 

 and simply cellular, fibrous or calcareous ; 

 their contents serous or glairy. The mamma 

 and ovary are the most frequent seats of the 

 clustered simple cyst. 



The compound cyst (cystoma) is charac- 

 terised by its faculty of producing secondary 

 cysts in its walls, these a tertiary series and 

 so on. Their closest investigator, Dr. Hodg- 

 kin, assigns them three chief varieties of 

 form, the pedunculated, the intermediate, 

 and the broad-based, for a full description of 

 which we must refer the reader to his treatise. f 

 The growth of the contained cysts is some- 

 times so active, as not only to give a nodulous 

 outline to the main mass (which may attain 

 enormous bulk), but to cause rupture of" the 

 walls of the primary cyst. Various morbid 

 changes, inflammatory and other, may arise 



* Todd and Bowman, Physiol. Anat. p. 130. 

 t Morbid Anat, of the Ser. and Muc. Mem* 

 brancs, vol. i. 



