M DEVELOPMENT OF CONNECTIVE TISSUE. 



systems of pathology. For tlie embryonal connective tissue, 

 with whose genesis we are now concerned, is identical with the 

 much-discussed embryonic tissue (Keimgewebe) of morbid 

 growth, with the plastic exudation of the humoralists, witli 

 Virchoio's "proliferation of connective-tissue corpuscles," with the 

 accumulation of emigrant leucocytes discovered by CoJmheini. 

 When we come to discuss the theory of inflammation we shall 

 have occasion to become acquainted with the data afforded by 

 morbid histology in reference to this question ; suffice it for the 

 present to say that the possibility of the mignition of colourless 

 blood-corpuscles, and the production of plastic exudations by 

 their accumulation and aggregation, has been placed on a sure 

 footing; while, on the other hand, the farther possibility of 

 fission of the pre-existing stationary corpuscles is not excluded ; 

 nay, must in certain cases be considered indispensable. 



§ 74. The subsequent metamorphoses of the young con- 

 nective tissue, the formation of intercellular substances of different 

 kinds, and the resulting constitution of the various members of 

 the connective-tissue series, I must assume the reader to have 

 learned from books on normal histology (see Rolletfs article in 

 Strieker s Handbook, Syd. Soe. transL, vol. i.). We will do well 

 to distinguish rigorously l)etween such connective substances as 

 constitute independent organs, or parts of organs, between the 

 formed or functionally active connective substances (cartilage, 

 bone, tendon, &c.), and the formless, passive connective tissue, 

 which serves only to fill up gaps, and which the older authors 

 -called "cellular tissue." Henceforth I shall employ the terni 

 ^' connective tissue" to designate the latter variety only; it is to 

 this variety alone that the statements made above concerning 

 the ubiquity of connective tissue in the human body, concerning 

 the affinity of its cells to those of the endothelium, concerning 

 its significance as a proximate constituent of the intermediate 

 apparatus of nutrition, refer. I must not be understood to 

 question the relationship of this variety of connective tissue to 

 the formed connective substances (geformte Bindesubstanzen) ; 

 on the contrary, it will appear in the sequel that a clear idea of 

 their relationship is of peculiar moment for the right interpreta- 

 tion of many morbid phenomena ; I only want, with reference 

 to the growth of organs, to establish a timely distinction between 

 those organs which are made up of the connective substances, 



