

CONNECTIVE TISSUE. 181 



both, a very bright strip demarcating the ribbon from adjacent 

 protoplasmic bodies. 



In the periosteal tissue of a new-born pup, therefore, we are 

 enabled to trace the transitions of different forms of medul- 

 lary elements into sometimes narrow, sometimes broad and flat, 

 spindle-shaped protoplasmic bodies. We become convinced that 

 by a gradual change of the latter arise both the " connective tis- 

 sue" and the " elastic fibers." 



The development of the connective tissue in general is a much 

 disputed, and to this day unsolved, question. 



In looking over the vast literature on this subject, we may sum up all the 

 views of prominent observers into two theories. One of these may be termed 

 the secretion theory; it implies that the intercellular- or basis-substance is pro- 

 duced by a sort of secretion of the cells frpm an originally homogeneous mass 

 between the cells. The other, which may be styled the transformation 

 theory, maintains that the cells themselves are transformed into basis-sub- 

 stance, either by a process of splitting in their entirety, or by a process of 

 transformation of the cell-protoplasm at its peripheral portions. 



Secretion Theory. Henle * was the first to assert that an originally homogene- 

 ous substance splits into nbrillee and bundles of fibrillae. According to Eeichert, 

 the homogeneous substance proceeds from a fusion of the cell-membranes with 

 an intercellular substance, and the fibrillae are only the optical expression of the 

 foldings of this substance. The fusiform cells present in embryonal connect- 

 ive tissue, according to Virchow, Bonders, Gerlach, and Kolliker, do not 

 share in the formation of fibers, but persist, as Virchow expressed it, as cells, 

 or are converted into a plasmatic canal-system. The last-named observer is 

 the originator of the idea that the intercellular-substance is a product of 

 secretion of the cells, and this view prevailed for quite a time. Among the 

 recent observers, A. Eollett, L. Eanvier, and I. Kollmann advocate the modi- 

 fied theory that fibrous basis-substance may, to a certain extent at least, orig- 

 inate independently of cells. 



Transformation Theory. Th. Schwann t first maintained that the cells, after 

 being elongated, split into bundles. After Max Schultze's discoveries concern- 

 ing the protoplasma, t the theory of Schwann was modified. Max Schultze held 

 that the fibrous basis-substance of connective tissue arises from a coalescence 

 of embryonal cells composed of protoplasm, and destitute of an investing mem- 

 brane, and that a thin layer of unchanged protoplasm remains around the 

 nucleus of the primary cell representing the connective-tissue cell. Lionel 

 Beale, in England, independently of the German observers, expressed sim- 

 ilar views ; he claimed that the connective tissue is originally made up of 

 elementary parts, consisting of germinal matter, and that subsequently a 

 part of the germinal matter is converted into formed material. According to 

 these views, the originally living protoplasm is, by chemical and morpho- 

 logical changes, transformed into the lifeless basis-substance, though the cen- 



* "Allgemeine Anatomie." Canstatt's Jahresbericht, 1845. 



t " Mikroskopische Untersuchungen," etc. Berliii, 1839. 



\ Reichert and Du Bois Reymond's Archiv. 1861. 



" The Structure of the Simple Tissues of the Human Body." 1860. 



