154 
Similarly we follow up the changes which, according to the 
most recent — shall we say advanced ? — teachings of science, 
are coeval with and cause death. The transformation from 
life unto death — otherwise of the aldehyde groups just alluded 
to — is, according to the same teaching, the change into one 
or another, or it may be all, of those chemical products; the 
names alone of a few, very few, I can now enumerate, thus : 
amyl- alcohol, amylamine, amyl-diethyl-benzene, amyl-methyl- 
benzene, and so on.* 
We follow up the definitions thus given, and here is what, 
by a recognised authority on such subjects, f we are led to. 
We ask, In what, precisely, do aldehyde groups consist ? We 
learn that “ they are derived from primary alcohols by elimi- 
nation of one or more molecules of hydrogen, without intro- 
duction of an equivalent of oxygen, so that they hold a position 
intermediate between the alcohols and the acids.” Again : 
“ Diatomic alcohols can yield by oxidation two classes of alde- 
hydes, according as one or two molecules of hydrogen are 
removed.” And so on. And then this sentence occurs : 
“ Only a few of these compounds have been obtained.” 
In what manner are theories, of which those stated are ex- 
amples, to be designated ? It has, indeed, been said “ that 
science is nothing but une langue bien faite ” ; or, in other 
words, that the one sufficient rule for discovering the nature 
and properties of objects is to name them properly.^ But in 
the quotations given, have the nature and properties of the 
objects indicated been so named ? 
13. In the second quarter of the present century, a London 
physician of eminence thus wrote regarding “ errors of con- 
ception,” and his remarks are appropriate to our present 
theme : — Whether their objects relate to real or imaginary 
things, the person “reasons very correctly ; he assumes things 
to be true, and reasons from those false premises with pre- 
cision. Instances of this prevail in the world in religion, 
philosophy, medicine,” &c. The author quoted from gives 
instances of such speculations from the works of an older 
writer ; he states that upon such assumptions many followers 
of the leader alluded to act as if they were truths ; that, having 
been taught such things, they uphold them as if they were 
realities ; that they do this because they have not the fortitude 
to exercise their own thoughts. Men professing these opinions. 
* Fownes’s Chemistry , 1877, p. 244. 
t Op. et loc. cit. 
$ Condillac ; see Meryon, Hist, of Med., vol. i. p. 189. 
