134 



in a tear of a section, I have seen, as I believe, three medul- 

 lated fibres spring from one of these irregular corpuscles, 

 one passing inwards, one to the siu-face, and one horizontally 

 (PL VII, fig. 4). In another instance I have seen a similarly 

 shaped corpuscle with three principal poles, which differed in 

 this respect, that both the deep and the horizontal process were 

 bifurcated (fig. 5). Trne p\-ramidal corpuscles are sometimes 

 to be met with among others of different shapes in the 

 apparent white substance beneath the broad band of hori- 

 zontal fibres which limits the grey matter. 



Hitherto we have dealt only with the arrangement of the 

 nerve corpuscles, nerve fibres, and nucleated matrix ; a few 

 words may be added on the composition of each of these 

 elements. As regards the matrix, I agree with the view of 

 Henle and MerkeP that it is not proper connective tissue, 

 but allied to protoplasm. It is not swollen, but made firmer 

 with boiling. 



Amdt, while right with regard to its protoplasmic nature, 

 is doubtless mistaken with regard to its fibrous character ; 

 the fibres which he and others have described being produced 

 by the coagulating effect of reagents. In sections which 

 have been exposed to only weak reagents the fibrous appear- 

 ance is absent ; and in the densely nucleated parts a ball of 

 protoplasm seems to surround each nucleus. Scattered 

 through this basis are granules of a substance probably allied 

 to cholesterine or protagon; but those granules are mere 

 chemical deposits, probably run into more distinct granules 

 after death, and certainly without structural connections. 

 Masses of matrix, with granules in them, are no doubt often 

 seen adhering to torn extremities of processes of the nerve cor- 

 puscles, just as Arudt has figured them; but it is the merest 

 hypothesis, to my mind not a probable one, to suppose that 

 those processes are structurally continuous with the adherent 

 substance or its granules. 



The medullated fibres of the convolutions are limited by 

 no membrane round the medullary sheath ; and that sheath 

 consists apparently of a uniform substance, probably enough 

 pure protagon, which softens and becomes semifluid or fluid 

 on addition of various substances such as oxgall. The nerve 

 corpuscles contain a similar, but not identical, substance, 

 which has already been alluded to, and to which they owe 

 their granular appearance. It runs into larger globules under 

 prolonged subjection to the action of dilute oxgall, but 

 remains entangled in the stroma of the corpuscle. In a 



' Henle's 'Bericht iiber die Forfschritte der Anat. u. Phvs. im Jabre,' 

 1S67, p. 63, and 1868, p. 58. 



