450 RECENT PROGRESS IN PHYSIOLOGY. 



nerve cell and the nerve cell alone. We see its dendrites branching 

 out in various directions, each alert to dance the molecular dance 

 assigned to it at once by the more lasting conditions which we call 

 structural, and the jnore passing ones which we call functional, so soon 

 as some partner touch its hand. We see the body of the cell with its 

 dominant nucleus ready to obey and yet to marshal and command the 

 figure so started. We see the neuraxon prepared to carry that figure 

 along itself — it may be to far distant parts, it may be to near ones — or 

 to divert it along collaterals — it may be many, or it may be few — or to 

 spread out at once among numerous seemingly equipollent branches. 

 And whether it prove ultimately true or no that the figure of the danc- 

 ing molecules sweeps always onward along the dendrites toward the 

 nucleus, and always outward away from the nucleus along the neu- 

 raxon, or whatever way in the end be shown to be the exact differences 

 in nature and action between the dendrites and the neuraxon, this at 

 least seems sure, that cell plays upon cell only by such a kind of con- 

 tact as seems to afford an opportunity for change in the figure of the 

 dance — that is to say, in the nature of the impulse — and that in at least 

 the ordinary play it is the terminal of the neuraxon (either of the main 

 core or a collateral) of one cell which touches with a vibrating touch 

 the dendrite or the body of some other cell. We can thus, I say, by 

 the almost magic use of a silver token — I say magic use, for he who for 

 the first time is shown a Golgi preparation is amazed to learn that it 

 is such a sprawling thing as he sees before him which teaches so much, 

 and yet when he comes to use it acquires daily increased confidence in 

 its worth — it is by the use of such a silver token that we have been 

 able to unravel so much of the intricate tangle of the possible paths of 

 nervous impulses. By themselves, the acquisition of a set of pictures 

 of such black lines would be of little value. But — and this I venture to 

 think is the important point — to a most remarkable extent, and with 

 noteworthy rapidity, the histological results thus arrived at, aided by 

 analogous results reached by the degeneration method — e-specially by 

 the newer method akin to that of Golgi, that of Marchi — have confirmed 

 or at times extended and corrected the teachings of exjjerimental 

 investigation and clinical observation. It is this which gives strength 

 to our present position ; we are attacking our i^roblems along two inde- 

 pendent lines. On the one hand we are tracing out anatomical paths, 

 and laying bare the joints of histological machinery; on the other hand, 

 beginning with the i^henomena, and analyzing the manifestations of 

 disorder, whether of our own making or no, as well as of order, we are 

 striving to delineate the machinery by help of its action. When the 

 results of the two methods coincide, we may be confident that we are 

 on the road of all truth; when they disagree, the very disagreement 

 serves as the starting point for fresh inquiries along the one line or the 

 other. 

 Fruitful as have been the labors of the past dozen years, we may 



