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great advance has been made in any branch 
of science, the question has arisen how early 
should this be incorporated in the teaching of 
that science; in a word, how closely teaching 
should follow research, and various answers 
have been given. 
That we are dealing here with a funda- 
mental question is obvious after a moment’s 
reflection. Shall we teach the beginner, in a 
judicious way, of course, the science as it is 
at the time in question, or shall we teach him 
what is not only hopelessly out of date, but 
what is known to be absolutely untrue? 
In answering this question we must take 
into account that the beginner of to-day is 
the advanced student of to-morrow, and the 
chemist of the near future. It is true that 
most of the beginners in any branch of sci- 
ence never pursue that science at any length, 
and to these perhaps the least harm is done 
by teaching the science in an out of date 
manner; but the question becomes more 
serious when we are dealing with those who 
propose to devote their lives to the branch of 
science in question. 
Why has the question that we are discus- 
sing arisen at this time? As is well known, it 
thas come to the front as the result of certain 
fundamental discoveries made in chemistry 
towards the later part of the last century. 
‘These are usually known as physical-chemical 
generalizations, because they were reached 
through the application of physical methods to 
chemical problems. 
I think the term “ physical-chemical” is 
unfortunate, because it may leave the impres- 
sion that we are dealing here with something 
different from chemical, while, in fact, we are 
Indeed, I think the term “physical 
chemistry ” is unfortunate, since it may lead 
to the conclusion that here is something that 
is not chemistry, while it is simply an inte- 
gral part of chemistry. I greatly prefer the 
term “general chemistry” or “generalized 
chemistry”; since the generalizations which 
have been reached in this field concern most 
vitally and fundamentally the whole science 
of chemistry. This same thought is echoed 
jn the title of Ostwald’s great work, “ Lehr- 
not. 
SCIENCE 
[N.S. Vou. XXXV. No. 890 
buch der allgemeinen Chemie.” The term 
“physical chemistry ” is, however, so widely 
disseminated, and the leading journals in this 
field in German and French both bear this 
title, so that the hope of reform in this nom- 
enclature seems remote. 
The generalizations that we have in mind 
are: The discovery of the Law of Mass Ac- 
tion, by the Norwegian physicist, Guldberg, 
and the Norwegian chemist, his son-in-law, 
Waage, in 1867; the discovery in 1886 of the 
applicability of the laws of gas-pressure to 
the osmotic pressure of dilute solutions of 
non-electrolytes, by one of the greatest men of 
science who has ever lived, Van’t Hoff; and 
the explanation by Arrhenius in the same 
year, of the apparent discrepancies presented 
by electrolytes, ¢. e., the announcement of the 
theory of electrolytic dissociation; of less im- 
portance perhaps is the interpretation of 
chemical valence in terms of Faraday’s law, 
but scarcely so, at least from the pedagogical 
standpoint; and finally, the discovery of the 
electron, by Sir J. J. Thomson, and the insta- 
bility of the chemical atom, by Rutherford. 
The question then is, shall these generaliza- 
tions be taken into account in the early stages 
of the teaching of chemistry, or shall they 
not? I know of no productive chemist who 
doubts the value of introducing them into 
more advanced stages of work. To do so 
would be to teach and learn a science of chem- 
istry, with the science all left out. 
A fair way to judge of the value of any dis- 
covery is to imagine that it had not been 
made, and see how the science would be af- 
fected by its absence. Similarly, in dealing 
with a question like the one under discussion, 
it would seem to me that a logical way to ap- 
proach it would be to ask, What is lost by not 
incorporating the modern advances into ele- 
mentary chemistry, and then what is gained 
by doing so? 
It is certainly true that if we omit these 
generalizations from the early stages of chem- 
ical work we are teaching something that is 
out of date. There can be no two opinions on 
this point. But this alone does not solve our 
problem. 
