1883.] Distinctions between Organisms and Minerals. 
153 
out testing their supposition experimentally. They found 
that living protoplasm has the power of reducing silver from 
a very dilute alkaline solution, whilst in dead protoplasm 
this property is wanting. By dint of a long course of inves- 
tigation they determined that this reduction could be due 
merely to the presence of the aldehyde-groups in the proto- 
plasm whilst living. In living protoplasm the aldehyde- 
groups of each molecule are brought in immediate proxi- 
mity with the amide groups of the next, and thus a consider- 
able intensification of the vital molecular motion ensues. 
But with increasing complexity and motility follows increas- 
ing instability. Apparently trifling agencies displace the 
molecules and their action ceases. During every such mole- 
cular displacement, which is in fa6t a combustion, heat is 
liberated. Hence the rise of temperature in fevers, and 
that which occurs upon death. On the other hand, when 
lifeless albumen is assimilated and converted into the proto- 
plasm of a living cell, heat becomes latent. The absorption 
of oxygen, and the formation of carbonic acid, in short, the 
whole process of respiration, becomes intelligible, since it is 
admitted that an increase of molecular motion promotes 
chemical action and consequently oxidation. Vital force, 
Herr Loew considers to be, in short, reducible to the tension 
of the aldehyde groups ultimately due to electric differences. 
Life is the total result which the protoplasmic structure 
yields by means of such vital force. Space does not allow 
us to reproduce here the experimental evidence which the 
authors here set forth in support of their theory. They trust 
that at any rate the first step has now been taken towards 
explaining the numerous mysteries which appear in the 
manifold fun< 5 tions of protoplasm. Even the cardinal pro- 
blem, the first origin of protoplasm upon our earth, seems to 
them only a question of time. 
Whilst wishing the authors good speed in the arduous 
task they have in hand, and whilst admitting that they have 
laid down a fair working hypothesis on the nature of life, 
which must stand or fall by its results, we wish to point to 
one difficulty. They appear to regard albumen and proto- 
plasm as substantially identical in composition. Now, 
according to the analyses of Reinke, referred to in the 
“ Journal of Science” for 1881, p. 182, protoplasm contains 
scarcely 30 per cent, of albuminous matter, and contains 
upwards of 40 proximate principles. The question now 
arises whether all these principles are truly components of 
the protoplasm molecule ? 
VOL. IV. (THIRD SERIES.) 
M 
