152 Distinctions between' Organisms and Minerals. [March, 
— such as alizarine, indigo-blue, vanilline — have become 
laboratory products. But chemists have failed in the 
synthesis of the more characteristically vital compounds, 
such as albumen. Further, till the year 1875, the idea of a 
chemical distinction between living and dead protoplasm 
was not even conceived. Prof. Pfluger (“ Pfliiger’s Archiv.,” 
x., p. 251) advanced the opinion of a necessary chemical 
difference between protoplasm in these two conditions. It 
may be well here to remark, for the benefit of such readers 
as are not conversant with modern bio-chemical research, 
that protoplasm is not an abstract idea or a mere theoretical 
body. It is a substance which can be obtained from certain 
plants — i.e., Ethalium septicum, and submitted to the investi- 
gations of the chemist and the microscopist. The idea was 
taken up by HH. O. Loewand Thomas Bokorny, of Munich. 
The former of these chemists in establishing a rational 
formula for albumen was struck by the circumstance that 
it contained a number of aldehyde-groups immediately bor- 
dering upon amide-groups. Such groups, according to 
modern chemical philosophy, must be distinguished by 
intense atomic motion. Hence, argued Herr Loew, this 
motion constitutes life, whilst the respective displacement 
of the aldehyde and amide-groups, and the necessary cessa- 
tion of the atomic motion involves death, it may be of a 
mere molecule of protoplasm, or of a larger portion, or of the 
entire animal or plant. Now, so far, we have to deal merely 
with a theoretical assumption. This point requires, there- 
fore, a little further explanation. The methods of the astro- 
nomer are utterly unintelligible to the majority, even of 
educated men. But when an astronomer on theoretical 
grounds predicts the existence of a hitherto unseen planet, 
and another, turning his telescope to the spot, discovers it 
there as foretold, the public is forced to admit that the 
hypotheses of astronomers deserve a great degree of confi- 
dence. Very similar is the case with the speculations of 
the chemist : no man has seen a molecule, much less an 
atom. No man can say, on the direct evidence of his 
senses, that in a molecule the atoms are arranged in this or 
the other manner. Nor has anyone witnessed the more or 
less rapid vibration which the atoms in a molecule, or the 
molecules in a compound body, are inferred to undergo. 
But when we find chemists setting out from these assump- 
tions come not by chance but intentionally to such results 
as the formation of artificial indigo, they are entitled to 
claim for their assumptions at least provisional acceptance. 
HH. Loew and Bokorny, however, were not content with- 
