74 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES 
taining visions of things seen, echoes of sounds, the sadness 
of grief, the fury of anger, the quiet power. of loving kindness, 
and forcing these at intervals upon the present consciousness. 
Such a concept might be compared to some ever-changing, ever- 
constant Niagara—perhaps the drops which make up that eat- 
aract are not more numerous or of more changing relationships 
than are the atoms which enter into ane metabolism of the 
neurone. 
As in all living cells, the metabolism of the neurone is con 
trolled by its nucleus. The functional integrity of the neurone 
depends upon its structural integrity. This quality, aiso, 
it shares with all other cells, as well as with organs of the 
body and with systems of organs. The nature of the nuciear 
influence upon the nutrition of the cell is yet the subject of 
much discussion. The nucleus is not large, probably not more 
than twenty-five microns (one-thousandth of an inch). The 
length of the axon is, In many instances, more than a meter. 
The nucleus, then, controls the nutrition of thirty million 
times its own mass of protoplasm. 
Rolleston has shown that nerves undergo a rise of tempera- 
ture at death. A number of observers find the normal aika- 
linity of both gray and white matter to be decreased after long 
stimulation. Halliburton and Brodie found the reaction acid 
shortly after death, but they were unable to render the splenic 
nerve of the dog acid to litmus during life, even by six hours 
faradisation. Hill, by applying Ehrlich’s intra vitam methy- 
lene blue method to nerve tissues, has shown that these changes 
represent processes of oxidation, as was to be expected. These 
statements are verified by the classic experiments of Dr. Waller, 
who has demonstrated a discharge of carbon dioxide upon the 
passage of impulses over the axon. It is evident, then, that 
the axon in itself has a certain metabolic activity, which is, 
“however, never independent of the nucleus. The investiga- 
tions of Donaldson and Hoke, in the Laboratory of Neurology 
of the Chicago University, show that the mass of the axon is 
approximately equal to the mass of the medullary sheath. 
This is found to be true in more than fifteen hundred measure- 
ments of nerve trunks of animals of more than twenty genera, 
representing fish, amphibia, reptiles, birds and mammals, in- 
eluding man. The phenomena of degeneration and regenera- 
tion also indicate that the function of the medullary sheath 
is metabolic. 
Neurones, in common with other somatic cells, are fed by 
lymph secreted from the blood by the endothelial cells of the 
capillary walls. Every nerve cell of the brain, probably of 
the whole nervous system, lies in a pericellular lymph space. 
