238 SPECIAL HISTOLOGY. 



proved, that in the higher animals, a similar division of the 

 contents is to be regarded as natural, and that into fibrils as 

 artificially produced. 



The diameter of the primitive fasciculi varies, not incon- 

 siderably, in different muscles, or in one and the same muscle. 

 Henle (who is followed by Gerlach), at an earlier period, 

 assigned to them a diameter of 0005 — 0006"', and at most of 

 001 7"', but more lately (Stadelmann, "Sectiones transversa?"), 

 has declared that these measurements are not universally 

 correct. I will here give some particulars upon which the 

 measurements stated above, in the text, are founded. In a 

 female, the fasciculi of the sacro-lumbalis measured 0016 — 

 0028'", the majority 0020 — 0-022'"; in the pectoralis major 

 0-01 — 003'", most of them 0-02'"; deltoid 0-016 — 0-026'", the 

 majority 002 — 0-022"' ; in the masseter 0-006—0-02"', the 

 majority 0-01 — 0-018'"; in the retr aliens auricula 0-006 

 0-015'", the greater part 0*008 — 001'". In a male, their 

 diameter, in the pectoralis, amounted to 001 8 — 0-28'", the 

 greater number measuring 0*02 — 0-022'"; in the deltoid 0012 

 —0-024'" for the largest, and for the smaller 0-016—002'"; 

 in the obliquus abdominis externus 0'16 — 0024'" and 00 16 — 

 002'"; in the orbicularis oris 0008— 0016'" and 0-01 — 

 0-012"'; in the frontalis 0006—0-014'" and 0-008— 001'". 

 In a second individual, the pectoralis major contained fibres 

 of 0-0068— 0-024'", most of them 0018— 002'"; the pyra- 

 midalis, some of 0-01—0-028"', the majority 0-02'". 



With respect to the nature of the primitive fibrils, much 

 still remains to be cleared up. In general they must be 

 regarded as solid, and in fact there is nothing to indicate the 

 existence of a cavity in them. It is fully ascertained, that it 

 is to them, that the transverse striation of the primitive fasci- 

 culus is due. It is still doubtful, however, whence the appearance 

 of transverse striation in the fibrils themselves arises; whether 

 from their being spirally twisted (Arnold) ; from zigzag 

 curvatures (Will) ; or from varicosities. All that I have seen, 

 leads me to adopt the latter view, which is also that most 

 generally entertained. I do not deny, that in the examination 

 of numerous fibrils, appearances are occasionally met with, 

 favorable to the other two views, and particularly to that of 

 Will, but it is much more usual to find simple nodular 



