WATER ESSENTIAL TO ALL LIFE. 229 



and millions tliere must be in a very thin layer ot a xQvy 

 small area of the grey matter of the cerebral convolutions 

 of the human brain. Hundreds and thousands of these 

 very minute cells act together — act consentaneously, not 

 only in thought but in voluntary movements. 



Cerebral action seems to depend on the living maiter of 

 these "■cells'' When the living matter is much injured, or 

 poisoned by tlie presence of certain poisonous matters in 

 the blood, their action is seriously deranged, or tlie result 

 may be fatal. 1 daresay while I am now speaking the 

 living particles of millions of my " brain cells " are actively 

 engaged at the same time, for the same purpose and in the 

 same direction. Of course I do not feel it, or understand it, 

 but from the arrangement of the living matter structure one 

 can see and study and think over, I cannot but feel pretty 

 sure it must be so. There is, I believe, no other explanation ; 

 and the conclusion I have ventm-ed to draw is certainly 

 justified by the facts ascertained by microscopical investi- 

 gation of the cortex of the cerebral convolutions of the 

 human brain in excessively thin and well prepared 

 specimens. If you were to see the actual appearances 

 under the microscope you would I think come to the same 

 conclusion. The statements involve much more than 1 am 

 able to describe, for it Avould indeed take a long time to 

 give but a short account of what I have seen in the course 

 of my investigations. But the broad fact to consider is that 

 the living matter of the " cells " Ave think with, must be 

 freely aerated, as they receive a direct and very large supply 

 of blood just oxygenated by having just passed through 

 the vessels of the lungs, I think a larger supply than is 

 received by most organs, except the lungs themselves. The 

 delicate " cells " and fibres are separated from one another 

 by fluid, thus being carefully protected from pressure or 

 shock, and the living matter in the centre of each cell is 

 constantly kept moist. As is well knoAvn, there is fluid not 

 only around the brain and spinal cord, but in all the 

 interstices of the brain tissues, by which the mi mite 

 bioplasts and fibres are kept from pressing on one another, 

 while probably many adjacent fibres may be carrying a nerve 

 current in different directions. 



A cousiderable quantity of water is required in all the 

 changes connected Avith the living matter of all " cells." If 

 you want to understand the action and movements of living 

 matter you have only to look at some of the " cells " in 



