135 



specimen immersed for some days in dilute liquor potassse, 

 and reduced to a pulp, this substance was run into masses, one 

 from each nerve corpuscle, and having a firm waxy appear- 

 ance contrasting with the pulpiness of the rest of the texture. 

 There are thus ajsparently three more or less waxy-looking 

 substances in the grey matter of the brain, to which the 

 attention of chemists should be directed to distinguish them, 

 viz. the matrix granules, the medullary sheaths of nerves, 

 and the granules of the nerve corpuscles. 



I have been able to verify the appearance of striation or 

 fibrillation which Arndt has remarked in the structure of 

 some of the nerve corpuscles. I do not see, however, that 

 this appearance is explained by the process of development 

 which Arndt imagines from what he has seen in the infant 

 brain ; and when he proceeds to dej)reciate the importance 

 of the nerve corpuscles, on the grouud that they have a 

 fibrillated texture, he is certainly very wrong. Contracti- 

 lity may fairly be taken as one of the most markedly vital 

 properties of texture ; and this property is exhibited in the 

 highest intensity by a texture which can easily be made to 

 show far more fibrillation than these corpuscles. He should 

 have remembered that however fibrillated the texture of the 

 nerve corpuscles may be, it is composed of albuminoid or 

 protoplasmic, not of gelatinous substance ; and it is in vain, 

 in the present state of our knowledge, to attribute to the 

 differentiated protoplasm of the nerve corpuscles a lower 

 amount of vital property than to the comparatively undiffer- 

 entiated protoplasm round about. 



The present teaching of science, with regard to the func- 

 tions of protoplasm in connection with the special properties 

 of nervous textures, may, I think, be fairly summarized thus : 

 that vital properties — to wit, irritability, contractility, sen- 

 sibility, selection of food, reproductive power, and capability 

 of development into differentiated vital tissues, are resident 

 in nucleated corpuscles consisting essentially of masses of 

 protoplasm ; and the various differentiated tissues referred to, 

 such as the nervous, muscular, and glandular, are specially 

 developed so as to exhibit in perfection certain of the pro- 

 perties of those bodies from which they all originally spring. 

 Taking this view, I see no objection to supposing that the 

 nucleated protoplasm of the brain may foster and facilitate 

 the actions of innervation ;' but it seems most probable that 



•^ In connection with the attributing of vital properties to the nucleated 

 protoplasm of the brain, it is interesting to note the curious observation by 

 \Valther of amoeboid movements in sections of a frozen frog's brain, referred 

 to in Henle's ' Bericht,' for 1868, p. 60. 



