180 E. A. Schäfer, 



which are seen in muscle in longitudinal view, and of the reticular 

 appearances seen in transverse view. According to the view taken 

 by those occupying' the other camp, a muscular fibre is not composed 

 of fibrils and muscle-columns in the sense above mentioned, but is in 

 its actual constitution composed of a uniform substance which is con- 

 tinuous throughout the length and breadth of the fibre, and which 

 occupies the interstices of a reticulum pervading the whole fibre; the 

 reticulum being composed of transverse networks which cross the fibre 

 at regular intervals and produce the cross-striae of the longitudinal 

 view and the reticular appearance of the transverse section, and of 

 longitudinal filaments which unite the transverse networks with one 

 another and produce the longitudinal striae of the longitudinal view. 

 The pervading idea of camp B was started by Retzius (who now 

 appears to have practically abandoned it) and its most powerful cham- 

 pions have been van Gehuchten and Ramon y Cajal. I suppose that 

 I must m) T self be regarded as a pioneer öf camp B since I expressed, 

 in 1873, a similar opinion so far as the continuity of the principal 

 part of the muscular substance is concerned, and also as regards the 

 lack of pre-existence of fibrils and muscle-columns in the living muscle. 

 These opinions were, however, founded on the appearances presented 

 by the living muscular fibres of a single insect and although those 

 appearances were described and depicted accurately, I have been long- 

 conscious that so limited a study of the subject was insufficient to 

 decide a question which bristles with difficulty. For some years, there- 

 fore, I have held aloof from the conflict of opinion which has been 

 carried on regarding this subject, making only such observations as 

 opportunity from time to time afforded, and reserving any decision 

 regarding the matter until I should find opportunity to re-investigate 

 such points as seemed to require elucidation. This opportunity I have 

 lately found, and as will presently appear, I have seen reason to 

 modify my earlier expressed opinions. 



Although the larger number of recent observers are ranged in 

 camp B, there is by no means unanimity amongst them as to what 

 is actually the contractile substance of the fibre, although most are of 

 opinion that it is the network and not the inter-reticular substance. 



