13G DK. MITCHELL BRUCE 



In regard to the " elastic stripe/' I cannot agree with 

 Boll at all. In a tendon, when the bundles lie parallel, and 

 the rows of cell-plates jjresent themselves to view from the 

 surfiice, I do not find anything of a median stripe ; but when 

 the row of cell-plates is seen in half profile there is visible on 

 one side of each of them, evidently Avhere it bends round, 

 and therefore is seen from the edge, something which may 

 be compared to the elastic stripe. On the other hand, I 

 must say that on some parts of tendons which do not exhibit 

 the bundles in a parallel disposition, and which are, therefore, 

 to be regarded out of their natural condition, irregular cell- 

 plates are to be found, which, when seen from the surface, 

 exhibit something like a median stripe. In this respect, 

 consequently, I agree with Boll, if it is meant that a folding 

 or a crumpling of the cell-plate may produce the appear- 

 ance of a median stripe. (Compare Torek's " Vorlauf. 

 Mittheil.," ' Centralblatt,' 1873, No. 5, p. 67.) 



I come now to deal with the question — have the fibril- 

 bundles of the tendon a sheath ? Boll agrees with the older 

 investigators in so far as he assumes with them that the indi- 

 vidual bundles are surrounded by a sheath; at least, he 

 assumes it as very probable. And this opinion he has arrived 

 at by studying the appearances presented by transverse 

 sections of tendons. Without being in a position with cer- 

 tainty either to deny the existence of a sheath or the fibril- 

 bundles, or to grant it, I must still mention that it is ex- 

 actly the appearance of a transverse section that can be satis- 

 factorily explained without accepting the presence of a sheath. 

 If we study, for example, the cross section of a tendon of 

 the tail of the rat from a gold preparation,^ we observe, 

 Avhat has been held by all authors, that the processes of the 

 stellate figures (which often contain a nucleus very distinctly), 

 break up into branches which reunite in such a maimer as to 

 make a network, each mesh of which is occupied by the 

 transverse section of a bundle. This appearance may be easily 

 explained when we reflect that each bundle is ensheathed by 

 nearly a half-cell-cylinder, so that the ring by which the 



^ I have obtained the best and most complete preparations of cross 

 sections of tendons in the following manner : — The distal half of the tail is 

 removed from the living animal, the skin stripped off, and the organ placed 

 in a half-per-cent. solution of chloride of gold for fifteen or twenty-five 

 minutes, after which time it is removed, and exposed to the light in 

 distilled water until it has become coloured. The tail is then placed in a 

 one-tenth or one-eighth-per-cent. solution of chromic acid for two or 

 three days, until the bones become softened, then transferred to alcohol 

 for a quarter or half an Jiour, and finally imbedded. The sections cut from 

 it should be washed in water and mounted in glycerine. 



