ty-five to forty-five. This fact is the source of frequent
fallacies when different countries or districts and different periods
are compared with each other, unless account is taken of the differences
in age and constitution. With regard to sex females are far more liable
than males; the respective death-rates per million living for England
and Wales in 1904 were--males 740; females 1006. But the two rates show
a tendency to approximate; the increase shown over a series of years has
been considerably more rapid among males than among females. One result
of more careful examination of statistics has been to discredit, though
perhaps somewhat hastily, certain observations regarding the prevalence
of cancer in special districts and special houses. On the other hand the
fuller statistics now available concerning the relative frequency of
cancer in the several organs and parts of the body, of which some
account is given above, go to confirm the old observation that cancer
commonly begins at the seat of some local irritation. By far the most
frequent seats of disease are the uterus and breast in women and the
digestive tract in both sexes, and these are all particularly subject to
such irritation. With regard to the influence of heredity the trend of
modern research is to minimize or deny its importance in cancer, as in
phthisis, and to explain family histories by other considerations. At
most heredity is only thought to confer a predisposition.

Treatment.

The only "cure" for cancer remains removal by operation; but improved
methods of diagnosis enable this to be done in many cases at an earlier
stage of the disease than formerly; and modern methods of surgery permit
not only of operation in parts of the body formerly inaccessible, but
also more complete removal of the affected tissues. Numerous forms of
treatment by modern therapeutic means, both internal and external, have
been advocated and tried; but they are all of an experimental nature and
have failed to meet with general acceptance. One of the most recent is
treatment by trypsin, a pancreatic ferment. This has been suggested by
Dr John Beard of Edinburgh in conformity with the theory, mentioned
above, that failure of the pancreatic secretions is the cause of cancer.
It has been claimed that the drug exercises a favourable influence in
conjunction with operation and even without it. The experience of
different observers with regard to results is contradictory; b