May 10, 1901.] 
The most difficult mental attitude, which 
the scientific man has to contend with in 
his struggle for the truth, is bias. We 
inherit, in a measure, certain notions of 
things and of life. This natural inheri- 
tance is strengthened by the earlier teach- 
ings of childhood, so when we reach the 
age of maturity we have formed certain 
Opinions, we are endowed with certain 
habits of thought which tend to dominate 
our mental attitude. Happily, most of 
these habits and most of these inheritances 
are sound, but now and then we find one 
which is clearly opposed to the conditions 
of existence as science reveals them. How 
difficult in this case to let go the old 
notion ; how hard to bring one’s self into an 
attitude to receive the truth! Perhaps it 
is only a species of conservatism which 
leads man to hold on to that which he has, 
and in this sense a certain difficulty of con- 
viction is a guaranty of stability of thought 
and of social, economic and political con- 
ditions. In other words, we should heed 
the warning in the Bible and not be swayed 
by every ‘ wind of doctrine.’ The tendency 
to too eagerly accept is more reprehensible 
than tardiness of belief. We have all seen 
wave after wave of illogical belief sweep 
over the country, and no difference how ab- 
surd a theory may be or how impossible a 
course of action which is marked out, it 
finds plenty of adherents. This instability 
_ tends to render all the conditions of natural 
growth and development precarious. The 
scientific man must be on his guard against 
being buncoed by any plausible or specious 
doctrine, as well as to keep his mind open 
for the acceptance of the truth. Here is 
where judgment comes into play, and not 
only should the scientific mind be open to 
conviction, but it should also be controlled 
by a sober and discreet judgment which can 
discriminate between the true and the false 
in evidence. But when soberly considered, 
certain facts are brought home with an 
SCIENCE. 725 
overwhelming evidence of truthfulness, the 
results of this evidence should be accepted, 
no matter how contrary they may be to our 
preconceived notions. Perhaps the greatest 
offense in this direction which the scientific 
man commits is a distortion of evidence to 
suit the case. By a slight inclination this 
way or that from the true point of direction 
an observed fact may be made to support 
this or that theory or condition. Iam far 
from belittling the value of theory. When 
formed on substantial evidence and with a 
becoming ingenuity it is a valuable aid in 
the discovery of further truth, but a theory | 
should never be a fetich to be reverenced 
and worshipped with the blind devotion of 
the religious devotee. There is nothing 
sacred about the theory. It is only a valu- 
able tool to be cast aside when a better or 
more effective one is at hand. The dignity 
of our profession, therefore, has been 
strengthened and increased by the habit of 
the chemical mind of accepting the dicta 
which experimental evidence has provided. 
Detracting somewhat, however, from this 
dignity has been the fact that certain con- 
tentions have arisen in our profession over 
the interpretation of ascertained phe- 
nomena. Chemists may agree upon the 
character of certain phenomena which are 
presented, but construe them differently, 
and often with acrimony. A scientific dis- 
cussion should be conducted with all the 
dignity of a scientific dissertation, and the 
honest differences between chemists should 
never be allowed to degenerate into per- 
sonalities or innuendo. There is no excuse 
whatever for speaking slightingly of the 
honesty or ability of a brother chemist who 
may happen to differ from you in his 
opinion of phenomena. Envy, backbiting, 
slander and scandal have no place in the 
chemical profession. I believe every one 
will admit that there has been less of it in the 
profession of chemistry than in almost any 
other. We know to what extent the per- 
