544 THE POSTERIOR PITUITARY AND THE NERVOUS SYSTEM. 



lene-blue and a modified chloride-of-gold stains were those 

 mainly used by Apathy, no confusion can occur on this score. 



Indeed, if we convert all of Apathy's neuro-fibrils into 

 minute capillaries, their identity as inherent parts of the gen- 

 eral circulation is placed on a solid foundation by the following 

 remark of Professor Barker's: "The doctrine of the fibrillary 

 nature of the axon and unstainable portion of the protoplasm 

 of the nerve-cell has recently received support from the studies 

 of Lugaro 39 and Levi. 40 The former, too, in his studies of the 

 nerve-cell under pathological conditions for example, after 

 poisoning with lead and arsenic finds that the fibrils may be- 

 come very distinct in the nerve-cells." That this directly points 

 to the one system through which the morbid changes can occur, 

 i.e., the adrenal system, and that it precisely coincides with the 

 foregoing remarks bearing upon this system, is evident. 



The similarity of the neuro-fibril, on the one hand, to the 

 axis-cylinder and its cell-body extensions, on the other, now 

 becomes a normal consequence. "Each neuro-fibril is," Apathy 

 states, "made up of a large number near its origin, at any rate 

 of 'elementary fibrils/ and in the course which it follows ele- 

 mentary fibrillaB are being given off at short intervals until 

 finally the neuro-fibril itself may be reduced to a single ele- 

 mentary fibril." The fibrillary structure of an axis-cylinder is 

 as clearly reproduced here as it can well be; the giving off of 

 fibrils but typifies the irregular distribution of "non-medul- 

 lated" nerve-fibers, and particularly those of the "sympathetic" 

 system. 



All this recalls a structure which appears to us to be inti- 

 mately connected with the general circulation, the neuraxon 

 and its cellular extensions, and Apathy's neuro-fibrils all 

 being considered as component parts of the general vascular 

 system: i.e., Virchow's neuroglia. 



The prevailing view concerning the role of this structure 

 is that it affords a supporting frame-work for the nervous ele- 

 ments. Both in the white matter and gray matter the medul- 

 lated nerve-fibers are separated one from the other by a net- 

 work of glia-fibers. In the gray substance, however, the neu- 



89 Lugaro: Rivista di patol. nerv. e mentale, vol. i, 1896. 

 * Levi: Rivista di patol. nerv. e ment., vol. 1, 1896. 



