Gilpin observer., 1906-01-04
DIFFER ON HERED1TY
TWO SCHOOLS OF MEDICINE IN
CONFLICT.
long-Accepted Idea Of the Direct
Transmission Of Disease Largely
Abandoned, but Predisposition to
Maiadies May Be Inherited.

Opinions have changed considerably
with reference to the connection be-
tween heredity and disease, says the
Medical Record. The belief was once
universally current that most diseases
could be transmitted directly to chill
dren, notably tuberculosis diathesis.
Clement Lucas, in the Wightman lee
ture delivered in London short time
ago, considered the question of hered.
itary bias and early environment in
their relation to the disease and de-
fects of children. The lecturer, while,
on the whole, inclined to agree with
the new views as to the transmission
of disease, thought perhaps that the
pendulum had swung somewhat too
far in that direction and that scarcely
sufficient attention was paid at the
present time to the influence of hered-
ity in the causation of some diseases.
For instance, he does not think that
the old observations as to the tuber-
culosis types of patients are quite val
ueless and is of the opinion that the
pearly sclerotics, the sharp, refined
features that may be seen in any vast
ing disease, may be produced by the
tuberculosis process. This may be
transmitted to the offspring. SO that
after few generations sufferers from
the disease would have the type oc.
curing in a healthy individual, and
merely indicating diminution of re-
sisting powers, perhaps to all diseases.
Malaria, again, formerly described as
a climatic diathesis, is now known to
be due to an organism conveyed by
the agency of mosquitoes. In the case
of cancer Lucas holds the view that
there are distinct grounds for doubt
ing the belief in the hereditary trans
mission of the disease
There Is, however in the affections
and abnormalities of the nervous sys-
tenn the clearest evidence of the in
fluence of heredity in disease. Fletcher
Beach has stated that of idiots 81
per cent have history of mental de-
fects in the family, 20 per cent OF
epilepsy and 16 per cent of alcoholism.
Gerrish has recorded an instance in
which, through five generations. pare
sis of the anterior tibial muscle ap-
peared between the ages of 2 and 26.
Deaf mutism, judging from statistics.
would also appear to be hereditary.
Notwithstanding the fact that hered-
ity is regarded, and rightly so, as not
having the preponderating influence in
the causation of disease which it was
once thought to exert, it may be ques-
toned whether hereditary influence is
not now too lightly regarded as
a factor in disease. tuberculosis is
not directly transmitted, but the pre-
disposition to disease is inherited. and
the descendants of tuberculosis for
bears are more prone to contract the
disease than those whose ancestors
were free from the malady. OF course.
the discovery that many diseases are
caused by microbes and the likelihood
that most organic affections originate
in the same way has unduly shaken
our belief in the influence of heredity
in disease. AS yet however. the proofs
that heredity exerts no influence in
this direction are not sufficiently con-
vincing to overthrow completely the
old views. The theory of heredity has
been modified, not overturned en-
tirely.