THE ENERGY OF THE LIVING PROTOPLASM. 185 
tion of 0.318 g. peptone, over î of it again in the urine, and after 
subcutaneous injection about §. Trypsin, present in minute 
quantities in all parts of the body, may gradually form amido- 
acids from the circulating protein ; also decompositions of an¬ 
other kind may simultaneously take place, whereby sugar is one 
of the products, which process can not only occur in the liver 
but also in the milt and kidneys (Lepine and Metvoz). The great 
amount of urea discharged a few hours after a meal may be due 
mostly to the amido-acids formed by the pancreatic juice from a 
part of the proteids of the food. 
The view of Nencki is further supported by observations in 
plants. In all cases where the proteids are attacked in plants to 
support respiration, a previous formation of amido-acids takes 
place, whose residues are finally found in form of asparagin (cf. 
Chap. V) (t) ; a synthetical product corresponding to the urea of 
animals. 
The view here taken as to the cause of respiration, corres¬ 
ponds in its principal feature to the definition Ncigeli gives of 
oxidising fermentation. 1 (2) This author says : “ the specific state 
of motion in the living protoplasm of the mycoderma cells is 
extended simultaneously to the alcohol and to the oxygen 
molecules. If, thus, the equilibrium is disturbed to a certain 
extent, chemical change takes place by aid of chemical affini¬ 
ties.” This theory, however, is still imperfect, as it does not 
show how the “ specific state of motion ” in the protoplasm is 
caused and does not define whether it consists of a molecular or 
of an atomic motion. (3) The new theory which assumes a 
chemical difference between the proteids of the living and those of 
the dead protoplasm furnishes the key to the “ specific state of 
motion it infers from physiological facts (cf. Chap. V) the 
presence of highly labile atomic groups, viz., aldehyde- and 
(1) Asparagin must be defined as the form in which ammonia is stored up in 
plants, whether it be formed by decomposition of proteids and amido-compounds or 
it be resorbed from tbe soil. Cf. Kinoshila, this Bulletin. 
(2) Theorie der Gärung, p. 43. 
(3) Nägeli published his “ Theorie der Gärung ” in the year 187g. A few years 
later, I often had discussions with him concerning the difference between living and 
dead protoplasm, which he had taken for a physical and anatomical one. Later on, 
however, he agreed that there must exist a chemical difference. 
