190 CONNECTIVE TISSUE. 



cells of the cornea and connective tissue generally." Thin obtained, by silver- 

 staining, appearances similar to Heitzmann's, but unfortunately misinter- 

 preted them. 



In 1879, Spina reviewed the subject. * He accorded to Heitzmann the 

 merit of the discovery, but as in the intervening seven years I alone had 

 publicly corroborated it, and he was not aware of that corroboration, he 

 thought that "the existence of cells with solid offshoots in genuine hyaline 

 cartilage is not definitely proved," and undertook to settle the question. 

 After many fruitless attempts, he found out a method of examination "by 

 which ramifying cells in hyaline cartilage can be demonstrated, not only with 

 ease, but also with certainty." The method and the results, as he has 

 described them, are as follows: "The cartilage, best the articular ends of 

 bones, is placed into alcohol for three or four days ; then the sections are 

 made and the examination is conducted in alcohol. From such specimens 

 positive proof is obtained that the cells of hyaline cartilage have solid off- 

 shoots. These offshoots emanate mostly from the body of the shriveled 

 cells, penetrate the basis-substance, and inosculate with offshoots of other 

 cells. Their number, and thickness are subject to numerous variations. . . . 

 The cell offshoots do not, as a rule, ramify. . . . Examination with powerful 

 immersion lenses (Hartnack, No. 15) teaches positively that the cell offshoots 

 not only pierce the capsule, but that the capsule extends also to the offshoots 

 themselves, so that at their origin they are surrounded, like the cell body, by a 

 wall. . . . Upon adding a drop of glycerine to the alcohol specimen, or on 

 staining it after one of the usual methods, the cell offshoots disappear more 

 or less rapidly; hence, it is clear that the hyaline, structureless aspect of 

 the cartilage basis-substance is really due to the methods of preparation hith- 

 erto in use, while, when examined in alcohol, as above described, the cell 

 offshoots invariably become visible." He added that he had succeeded a few 

 times in seeing faintly only, it is true the same structure in living hyaline 

 cartilages. On incorporating, for a sufficient length of time, carmine into 

 the body of frogs, Spina found cartilage corpuscles of which the nuclei, the 

 body, and the offshoots had taken in some of the coloring matter. As the 

 offshoots disappeared and the carmine granules seemed to lie in the hyaline 

 basis-substance when a drop of glycerine was added, it is easy to see how 

 previous investigators came to be misled into supposing the coloring matter 

 to have passed into the hyaline substance and into interfibrillar fissures. 

 With excessive caution, Spina adds : " Whether they (the coloring particles) 

 can also move along outside of the cell offshoots has not yet been proved." 



In the same year Prudden,t and, in 1880, Flesch, t also described cilia-like 

 processes of cartilage corpuscles ; and the latter admitted that in exceptional 

 cases he had succeeded in tracing them more or less distinctly into the basis- 

 substance. 



Varieties of Cartilage Tissue. Cartilage is a very dense, 

 opaque, and highly elastic tissue, the basis-substance of which is 

 not strictly gelatinous, as on being boiled it yields a cloudy, 



* " Ueber die Saf tbahnen des hyalinen Knorpels," Sitzungsber. der K. Akad. d. Wiss. in 

 Wien, Ixxx., Abth. iii., November, 1879. 



t " Beobachtungen am lebenden Kuorpel." Virchow's Archiv, Ixxv., 1879, p. 185. 

 t Loc. cit., pp. 59-63. 



