ON THE STRUCTURE OF TENDON. 131 



The material which I have made use of in studying the 

 structure of tendon, is that to be found in the tail of young 

 and grown rats, as well as in the tail of the young rabbit, 

 and the results which I have arrived at on the subject will 

 be found in some respects to agree, in some respects to dis- 

 agree, with those obtained by Boll. 



In the first place, following Ranvier's method, I removed 

 the tail of a young rat or rabbit, isolated the very fine 

 tendons contained in it, and mounted specimens of them in 

 a drop of fresh serum. Here I found numerous tendons, 

 consisting of wavy bundles which cross each other, as well as 

 a smaller number of tendons composed of bundles which were 

 straight or wavy, but parallel, and of a homogeneous appear- 

 ance. When I now used a greater magnifying power (over 

 400), and carefully observed such a tendon, there came into 

 view, a short time after the specimen Avas mounted, peculiar 

 systems of clear lines. There were, indeed, to be seen, from 

 place to place in the various depths of the tendon, but especially 

 near its surface, groups of shorter or longer clear lines which 

 were arranged transversely to the long axis of the bundle, 

 while their length did not exceed the breadth of a bundle, and 

 they were placed in every case so as to form the boundaries 

 of spaces of equal breadth. In some places these clear trans- 

 verse lines were limited to the alternate bundles ; on the most 

 superficial bundles, however, they were found upon two or 

 three neighbouring ones, in which case they were united at 

 the conjoined border of two contiguous bundles by a longi- 

 tudinal line corresponding to it, so that two or three con- 

 tiguous superficial bundles appeared at such places as if 

 covered with a mosaic, mainly of quadrilateral plates. 



I next added very cautiously to such a specimen a dilute 

 solution of acetic acid ; the spaces so defined then became 

 distinctly granular, and within them there came gradually 

 into view a roundish nucleus, while the lines uniting the 

 cells mutually in contact lost the clear appearance they pos- 

 sessed in the fresh state and became dark. In addition to 

 the nuclei mentioned there appeared on many other places 

 rows of oblong or staff'-shaped nuclei lying imbedded in a 

 very limited clear rectangular space, each pair of nuclei 

 being separated by a short transverse line. 



When the action of the acetic acid was increased in inten- 

 sity, either by increased strength of the reagent or by its more 

 prolonged application, a different and highly significant ap- 

 pearance was found to be produced. While the tendinous 

 bundles became considerably swollen and transparent, the 

 quadrilateral plates became increased distinctly in breadth, 



