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HANDBOOK OF PHYSIOLOGY. 



Krause's membrane, which passes from side to side from the sarcolemma 

 across the light stripe. This membrane corresponds to Dobie's line. 

 The transverse compartments are divided longitudinally into smaller 

 ones by lines which correspond with the boundaries of Cohnheim's areas, 

 and each such compartment is termed a muscle casket. Within the 

 middle part of the casket is a muscle prism made up of darker rods of 

 contractile material called muscle rods, and above and below the muscle 

 prism is a more fluid substance. When the muscle contracts, the fluid 

 substance is pressed more between the muscle rods, causing them to be 

 further away from one another. 



Muscle Reticulum Theory. According to the views of certnin 

 observers (Retzius, Melland. Marshall, van Gehuchten, and Carnoy), the 



Fig. 88A. 



Fig. 88. Transverse section of one of the truuk muscles of the Hippocampus, stained in chloride 

 or gold. (Rollett.) 



Fig. 88A. Portion of muscle-fibre of Dytiscus. showing network very plainly. One of the trans- 

 verse networks is split off, and some of the longitudinal bars are shown broken off. (After Melland.) 



part of fresh muscle which is stained in chloride of gold, is a meshwork 

 of fibrils which corresponds to the intracellular meshwork of ordinary 

 protoplasmic cells, i.e., the spongioplasm, and is the part which is the 

 contractile element in muscle. The meshwork on one level is connected 

 with the meshwork on another level by means of longitudinal fibres, at 

 the junction of which the meshes appear more or less knotted (figs. 88 

 and 88A). The longitudinal fibres of the network are, according to this 

 theory, the chief agents in the active contraction. The transverse mesh- 

 work is more passively elastic, and may be the cause of the speedy relax- 

 ation of muscle after contraction has ceased. The material filling up 

 the meshwork is a more fluid and non-contractile material. 



Rollett has minutely criticised the idea of the gold-staining sub- 

 stance of the fibre being the contractile portion. His views are the 



