IO 
MODERN STEPS OF PROGRESS. 
and that this form is changed by the fixation of water when the 
cell dies : 
. CN + H 2 0 = . CO NH 2 
But it may be here objected, that such changes do not take 
place spontaneously or easily. 1 ) 
The conclusion however that a chemical difference exists 
between living and dead protoplasm is plain logic.— If the dead 
matter of our food is converted into the living matter of our 
nerves, muscles and glands, a considerable chemical change 
must take place and just in the opposite direction to that 
connected with the loss of life. Pflüger ( 1 . c.) expressed his 
conviction in the following words: “An albumen-molecule, 
which in the brain concurs in the production of thought, which 
in the spinal column mediates sensation, which in the muscles 
performs mechanical work or in the glands starts chemical 
activity, is doubtless derived from the same dead albumen of the 
blood, but it is changed in chemical character as soon as it 
enters the living cell. 2 ) From the moment it forms a part of the 
living protoplasm, it commences to respire, to live. Only the 
cells have the property of life ; such albumen, which has not 
become protoplasm, is dead albumen, even in the living body.” 
The deductions of Pflüger did not attract the attention they 
deserved, they were even ignored by most physiologists. The 
cause may be found on the one hand in want of knowledge of 
the progress of modern chemistry, and on the other in the reac¬ 
tionary situation created by the echo of the “ ignorabimus ” of 
1872, still vibrating through the sultry atmosphere. Foremost 
among those who assented, stood of M. Nencki, who declared 3 ) : 
“ I have repeatedly expressed my opinion, that investigation into 
the albuminous bodies must take a new direction, if we want to 
ï) Pflüger had here evidently the comparison with nitriles in view. Certain 
other cyanogen-combinations, as cyanic acid, cyanamid, which undergo spontaneous 
changes, of course can not serve here for comparison or explanation.— 
2) This production of living matter from dead was declared by Pflüger to be one 
of the greatest enigmas of nature (Die allgemeinen Lebenserscheinungen, Bonn, 1889). 
1 he supposition of Pflüger that Liebig entertained the belief in a chemical difference 
between albuminous matter in living and dead cells, is an error. Nowhere in 
Liebig's writings can a decisive opinion be found. 
3) Arch. f. exper. Pathol, und Pharmacol. Vol. 20, p. 343. and Journ. f. prakt. 
Chem. Vol. 26. 
