118 NERVOUS TISSUE. 



salts in the brain of an insane patient, whilst, according to Vau- 

 quelin and Fremy, 6^ is the smallest normal quantity. 



Schlossberger* has recently made the remarkable observation 

 on the brain of a child which died at birth, that, in the first place, 

 the corpus callosum in new-born infants is as rich in water as the 

 grey substance; further, that the quantity of fat is nearly the 

 same at this age in the grey and white substance; and, finally, 

 that the brain of new-born infants is generally much richer in 

 water and poorer in fat than the brain of adults. 



Schlossberger found that the quantity of water in the brain of 

 the child referred to, varied only in different parts from 8 7*4 to 

 89-6, whilst the fat fluctuated between 4'5 and 3'8. 



When we pause to inquire whether any important conclusions 

 can be deduced from the chemical investigations hitherto instituted 

 in reference to the nervous mass, as to any special function of the 

 nervous system, we are obliged to admit the complete insufficiency 

 of our chemical knowledge. But, however forcibly we may be 

 compelled to admit the incapacity of chemical assistance to explain 

 the actions of the nervous system, chemists will not suffer them- 

 selves on that account to be deterred from further investigations ; 

 for they must be well aware that, without a careful examination of 

 the chemical phenomena presenting themselves in the nervous 

 system, they can never succeed in tracing nervous action to definite 

 physical laws. The very great significance of the axis-cylinder dis- 

 covered by Remak, and termed by him " the primitive band," the 

 important discoveries of Dubois regarding electric currents in the 

 nerves, and the minute and ingenious physiological experiments on 

 the different functions of the individual systems of nerve-fibres 

 and cells, will not afford us any deeper scientific insight into the 

 general functions of this most delicate of animal matters, or justify 

 us in establishing definite laws, and not merely individual propo- 

 sitions or rules, until we shall succeed in forming for ourselves a 

 mental representation of the reciprocal actions of the chemical 

 substrata when the nerves are in a state of activity. If observers 

 should ever succeed in detecting the presence in the nerves of a 

 peculiar agent, active only in living animals, or if the propagation 

 of nerve-force, and the corresponding phenomena of reflex action, 

 irradiation, &c., should be found to depend upon electrical currents 

 passing through cylinders endowed with more or less thoroughly 

 isolating walls, chemistry must still be called to our aid if we wish 

 to obtain an exact physical explanation of such phenomena. 

 * Ann. d. Ch. u. Pharm. Bd. 86, S. 119-125. 



