1896 - 97 .] 
Chairmans Opening Address. 
183 
conceptions were founded on the microscopical scrutiny of sections 
prepared by the older methods of hardening and staining, from the 
time of Lockhart Clarke to nearly the present day. 
The notions of physiologists, as is usually the case, were more or 
less in conformity with, and were influenced by, these histological 
conceptions. Nerve cells were supposed to be excited by nervous 
impulses, or to originate nervous impulses, and nervous impulses 
appeared to pass from cell to cell. Many illustrations, some fanci- 
ful, were culled from the nomenclature of electrical science. 
Notions also of more or less “ resistance ” in the passage of nervous 
impulses passed into current use. These notions were founded on 
the statement of the histologists that there w T as continuity of 
nervous elements, and they were derived from a fanciful analogy 
to the passage of electricity along conductors. No one offered 
proof of anything similar to resistance (in the electrical sense) 
occurring in a nerve ; and the term resistance, in nervous pheno- 
mena, was employed to explain certain cases of delay in the 
transmission of a nervous impulse in centres, and of an apparent 
choice of path by the nervous impulse. Further, there was no 
recognition of a nervous structural or physiological unit, unless in the 
separation of the nervous elements into cells and fibres ; and these 
two were often discussed as if they were separate and distinct. 
In science, the invention of a new method of research, by bringing 
to light new facts, or by upsetting notions founded on incorrect 
observation, leads not only to a critical examination of older 
ideas, but the formation of new ideas. A new method marks a new 
step in progress. For a time, things seem to be in confusion; old 
pathways have to be abandoned and new ones opened up ; and it 
is not until a fresh theory has been devised to meet and embrace 
the new facts that men feel they are again on safe ground. 
With regard to the physiology of the nervous system, we are at 
present passing through such a critical, and, it must be confessed, 
a dark period, in consequence of an entirely new set of facts having 
been elicited by a new method, now well known to histologists, in 
the preparation of sections of the nervous organs for microscopical 
examination. The method, first devised by Golgi, and applied 
with much success by Ramon y Cajal, Retzius, and many other 
observers, consists in acting on the nervous organs with bichromate 
