126 NATURE OF NERVE CURRENT. 



accuracy of Beale's anatomical view of the nerve ter- 

 mination, I can see no reason for doubting that 

 glandular protoplasm may be influenced directly by 

 the vis nervosa, even if the nerves are distributed 

 as he supposes, just as all protoplasm is suscep- 

 tible to the stimulus of heat, electricity, and other 

 active forces, although we may not yet understand the 

 exact mode in which the force is transmitted. The 

 same remark applies to the direct action of nerves on 

 nutrition, under certain circumstances. Of this there 

 are too many well- ascertained examples* to be ex- 

 plained away by the argument of Dr. Beale viz., 

 that nutrition and growth take place independently 

 of all nervous action, and are, in fact, most active 

 before the nerves themselves are formed. Because 

 these operations take place under other stimuli, with 

 pabulum and conditions, than nerve stimulus, that is 

 no reason why nerve stimulus should not influence 

 them when developed; not, of course, in any sense 

 being the source of their vital power, but merely rousing 

 that into activit}^ like other stimuli. Dr. Beale seems 

 lately to have changed his opinion on this subject. 



On the Nature of the Nerve Current. The chief 

 theories of the nature of the vis nervosa are first, 

 that it is a molecular force, like electricity ; or, second, 

 that it is electricity itself; or, third, a chemical action, 

 propagated from particle to particle, liberating energy, 

 like a train of gunpowder set on fire by a spark at . 

 one end. To this last, Dr. Beale objects that, if by 



* See Laycock's papers in the " Medical Times," also H. Power's, 

 in the " Practitioner," 1873 ; also Ranke, "Physiologic," p. 83, and 

 many other sources. 



