THE SARCOLEMMA. 85 



lemma does not differ very much from syntonin. It is dissolved 

 with nearly equal rapidity by dilute alkalies ; it swells in concen- 

 trated alkalies, dissolving very rapidly when water is added. It 

 behaves in precisely the same manner as the substance of the 

 fibrils towards concentrated acids, as, for instance, nitric acid. A 

 difference is observed in the case of acetic acid, and of the mineral 

 acids, when extremely diluted ; for, although these reagents render 

 the nuclei more distinct, they exert a certain amount of solvent 

 action upon them; the nuclei wholly disappearing after a pro- 

 longed digestion in dilute acids, leaving only some fine molecules, 

 which probably consist, for the most part, of fat. 



We may readily convince ourselves that the clots or granules 

 visible in the sarcolemma which has been emptied by acids or 

 alkalies, consist for the most part of fat, either by repeatedly 

 shaking with ether the remains of muscular fibres that have been 

 treated with a dilute solution of soda, or, better still, by repeatedly 

 boiling them in alcohol ; for we can not only recognise the presence 

 of fat in the ether or alcohol, but fewer clots and granules can be 

 detected under the microscope in the less granulated sarco- 

 lemma. 



Kolliker* and Scherer have demonstrated that the sarcolemma 

 does not consist of connective tissue, and that it yields gelatin on 

 boiling ; and this view is confirmed by the above-mentioned micro- 

 chemical reactions, which show most obviously that its chemical 

 substratum has no affinity whatever to protein-bodies. If we bear 

 in mind that neither acids nor alkalies cause the sarcolemma to 

 lose its elasticity, which, as in the case of elastic tissue, resists 

 alike the action of alcohol and boiling, we shall be led to concur in 

 Kolliker's opinion, that the sarcolemma contains a substratum 

 analogous to the elastic tissue ; but it is by no means easy to deter- 

 mine whether, like elastic tissue, it acquires a yellow colour from 

 the action of concentrated nitric acid. Kolliker was unable to 

 produce any yellow colour in the sarcolemma of the Axolotl by 

 means of nitric acid. As may be inferred from the above-described 

 micro-chemical relations of nitric acid towards the muscular fibre, 

 the sarcolemma cannot be isolated and distinguished in the flesh 

 of the higher animals; but the yellow colour produced in the 

 elastic tissue by nitric acid is not so distinctly visible on a micro- 

 scopical examination as in the protein-like tissues, and on that 

 account the microscope can afford no reliable information in 

 reference to this point ; when it occurs on a large scale, the elastic 

 * Mikrosk. Anat. Bd. 2, S. 250. 



