372 



In order to see that it is not really striped, but simply- 

 folded like a cloth, it is necessary to use a powerful object 

 glass of considerable angle of aperture. These different facts 

 show that the elements which appear contorted after the 

 action of acetic acid upon the tissue, for example, the elastic 

 fibres, and the germs of the smooth muscular fibres, owe this 

 form to the action of the reagent upon the intermediate sub- 

 stance. It is this of which we may be assured by direct 

 observation of the tissues, and employing tension before 

 using acetic acid. The cellular tubes exist in all tendons, 

 but they vary a little in their form, according to the tendons 

 submitted to examination. The rods which represent the 

 rolled up nuclei are more or less long, and the interval which 

 separates them one from another is more or less extended ; 

 this interval has often a length equal to, even superior to the 

 little rods themselves. Level with the interval, the sheath 

 becomes contracted, in such a way that the tube taken as a 

 whole presents a moniliform appearance. Almost always 

 the little rod which represents the rolled \\p nucleus is 

 bounded at its extremities by a transverse line and appears 

 cylindrical. The interval which separates the little cylinders 

 is occupied by a granular substance, which is nothing else 

 but a portion of the flat rolled-up cell itself. The tendo 

 Achillis of a frog supplies cellular tubes, such as have just 

 been described : by compressing them after the addition of 

 acetic acid, the opening and the unfolding of the cellular 

 tubes is brought about. 



After having placed the tail of s[ Rodent in a concentrated 

 solution of picric acid, at the end of some days the vertebrae 

 have lost their calcareous salts, and are become soft, whilst 

 the fibrous parts have acquired consistency. It is easy 

 then to effect very fine transverse sections, which compre- 

 hend at once the bones, the tendons, the nerves, and the 

 vessels. These sections, placed for several hours in the 

 picrocarrainate of ammonia, steeped, and examined in the 

 mixture of glycerine and formic acid, show at the surface of 

 the tendons the most beautiful plasmatic network (fig. 5) ; 

 but this is merely in appearance. It is necessary to be very 

 careful, as Henle said some time ago, not to mistake these 

 star-like figures and anastomoses for canaliculated networks 

 and for plasmatic cells. Already, with a little attention and 

 an object-glass at a considerable angle of aperture, it may be 

 observed that the star-like figures are limited by partitions 

 extending through the whole depth of the preparation. This is 

 seen still better when the cutting is slightly oblique to the 

 axis of the tendon. 



