ELECTRO-PHYSIOLOGY 



CHAP. 



almost imperceptible, before any other alteration due to the trans- 

 formation can be discovered." The strong surf ace -growth of 

 lamellae depends (as Engelmann showed), previous to the forma- 

 tion of loculi, essentially upon multiplication of the fibrils at the 

 periphery of the lamellae, not upon the thickening of those which 



a b e 



FIG. 254. Raja clavata. Successive stages in the development of an electrical plate from a cross- 

 striated muscle-fibre. (Engelmann.) 



already exist, or upon the widening of the inter-fibrillar spaces. 

 Later on, in the perfected organ, no fibrillated structure of the 

 lamellae can be detected. 



If the optical alterations in the series of strata during the 

 development of the electrical are compared with those seen in 

 vigorous, physiological contraction, there are striking coincidences, 

 as pointed out by Engelmann. On the one hand, the arimetabolous 



