102 0. F. MARSHALL. 



transverse networks comes into play, and they shorten to their 

 original dimensions, and by fluid pressure extend the longi- 

 tudinal fibrils to their original length, the elastic sarcolemma 

 aiding in the process. 



The alternate action of the longitudinal and transverse net- 

 works no doubt causes the special features of the contraction 

 of striped muscle, viz. the quick response to stimulus and 

 the rapid contraction ; and we have seen that the network 

 is developed wherever rapid movements have to be per- 

 formed. 



In connection with the foregoing considerations, the results 

 of Gerlach, Retzius, and Bremer, should they prove to be 

 correct, are of importance. I think there is little doubt that 

 the longitudinal striae described by Gerlach are identical with 

 the longitudinal bars of the network figured by Retzius, 

 Bremer, Melland, and myself. Gerlach traced these strise into 

 connection with the nerve endings. Retzius showed the con- 

 nection between the muscle-corpuscle and the transverse strise, 

 and Bremer traced the axis cylinder of the nerve into direct 

 continuity with the muscle-corpuscles. It therefore appears 

 that the network is connected with the nerve, and that the 

 longitudinal bars are connected with it indirectly through the 

 transverse networks. The direct continuity of the network with 

 the nerve does not necessarily imply that the network is itself 

 nervous ; in fact, it really supports the view that it is the part 

 actively concerned in contraction ; for we should expect a 

 priori, that if a differentiation occurred in muscle it would be 

 with the contractile part that the nerve would be in continuity. 

 On the other hand, with regard to the transverse networks* 

 it is possible that they may be in part nervous in nature, and 

 have for their function the more rapid conveyance of the 

 stimulus through the muscle ; and that the more rapid response 

 to stimulus, the special characteristic of striped muscle, may 

 be partly explained in this way. 



There are two obvious objections to the. theory of contrac- 

 tion we have arrived at, which I shall proceed to discuss : 

 1. It necessitates a difference between the longitudinal and 



