10 



MODERN STEPS OF PROGRESS. 



and that this form is changed by the fixation of water when the 

 cell dies : 



. CN + H 3 0= . CO NIL 

 But it may be here objected, that such changes do not take 

 place spontaneously or easily. r) 



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. Pflilger (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, whrch 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 Pfliiger 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 



1) Pfliiger had here evidently the comparison with nitrilcs 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 fiom dead was declared by Pfliiger to be one 

 of the greatest enigmasof nature (Die allgemeinen Lebenserscheinungen, Bonn, i88g). 

 The supposition of Pfliiger that Licb'g entertained the belief in a cltcmical 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. 



