THEIR MICRO-CHEMICAL RELATIONS. 77 



homogeneous, this must be still more the case with the primitive 

 bundles. We have already referred to the nuclei on the surface of 

 the muscular fibres; the elementary fibrils themselves, however 

 nearly they approximate to one another, or however closely they 

 are invested by the sarcolemma, are yet connected by an interme- 

 diate substance, which is itself of a double nature ; for, in the first 

 place, certain distinguished microscopists have observed, on trans- 

 versely cutting through a muscular fibre, that there is a granular 

 and molecular substance lying between the extremities of the indi- 

 vidual fibrils ; and secondly, we can scarcely seek for the juice, 

 which has been so admirably investigated by Liebig, elsewhere than 

 within the sarcolemma of the primitive bundles, which it appears 

 to permeate. 



We must, therefore, separate our chemical investigation of the 

 animal muscles into several sections ; of these, passing over the ever- 

 present connective tissue of the perimysium as not at present con- 

 cerning us, the numerous ramifications of blood-vessels, the nervous 

 twigs, and the sparingly scattered lymphatics, the micro-chemical 

 investigation of the sarcolemma and of the cylindrical bundles of 

 fibrils within it demands our special attention ; from this we will 

 pass to the macro -chemical reactions, which can be exhibited with 

 muscular tissue, terminating our inquiries with the examination of 

 the parenchymatous juice. 



Very dilute acetic acid (1 part of acetic acid in 5000 parts of 

 water) causes the primitive bundles of the muscles to swell very 

 rapidly, and to assume an extremely pale colour ; after a prolonged 

 action of two or three or even four days, we observe that the bun- 

 dles are much swollen, that the transverse striae are very distinct, 

 and approximate more closely to one another, and that the nuclei 

 parallel to the long axis of each bundle are very narrow, elongated, 

 granular, and not sharply defined ; many of them are constricted 

 at four or five points, whilst others protrude with the muscular sub- 

 stance from the sarcolemma, and are scattered about transversely 

 and obliquely in relation to the axis of the muscular bundles. 

 There is never any appearance of longitudinal striae (indicating the 

 existence of primitive fibrils) in the muscular substance itself; on 

 the other hand, a transverse striation may often be distinctly per- 

 ceived. At the cut extremities of several primitive bundles we 

 may frequently recognise portions of muscular substance, corres- 

 ponding to an individual transverse striation, and which, without 

 having any distinct form, such as Bowman has delineated, clearly 

 show the division of the muscular fibre in the direction of the 



