JUNE 10, 1915 | 
NATURE 
413 



tion of the film, support for our line of reasoning. 
The substances present in tobacco—probably the in- 
tensely allxaline substance nicotine in chief—set up in 
the cell those same electro-negative conditions which 
cause or assist it to promote the formation of the 
latent image, and in this way locally precipitate a 
state of mitotic instability which from other causes— 
to be presently discussed—may prevail as a tendency 
throughout the body cells of the patient. Local 
mechanical stimuli may contribute. It is, of course, 
not impossible that in many cases of the kind the 
effect is so far due to the local causes that but for 
these the cancer would not anywhere have invaded 
the body. 
According to Dr. W. S. Bainbridge (‘‘The Cancer 
Problem,” p. 67; New York: The Macmillan Co.), 
“cancer of lip, tongue, cheek, and buccal mucous 
membrane is of relatively frequent occurrence in both 
sexes in India, in consequence of the chemical irrita- 
tion produced by the chewing, or holding in the 
mouth, of a mixture of betel leaves, areca nut, tobacco, 
and slaked lime.” 
The seeds of Areca catechu are rich in tannin and 
also contain arecolin, an alkaloid closely related to 
nicotine, being, in common with it, a derivative of 
pyridine. Choline, a strong base answering the 
general reactions of alkaloids, is also present. The 
betel leaf is the leaf of Piper betle, and contains yet 
another alkaloid of the pyridine group—piperine (Haas 
and Hill, ‘‘Chemistry of Plant Products’; London : 
Longmans, Green and Co., 1913). It is worth noting 
that in this case both sexes suffer the increased 
liability to mouth cancer, and both sexes indulge in 
the habit. 
An increase in the number of deaths from malignant 
disease within recent years is admitted by high 
authorities to be the only conclusion we can draw 
from the statistics, after every allowance for error has 
been made.*7 Modern advances in surgical and medi- 
cal science undoubtedly enable life to be prolonged in 
many Cases, or even cure to be effected where formerly 
speedy death alone must ensue. This ought to be a 
set-off against improved diagnosis as a source of error 
in the statistics. If this increase is a fact, we have 
to look around for the cause. It is, assuredly, not 
founded in anything of an evolutionary nature. I say 
this because if its origin be in the cell itself, a very 
profound change—profound because seated in the 
primary organic structure—must be supposed to have 
taken place within a few decades. Indeed, if the 
increase is what we iudge it to be from the figures, it 
has taken place within a single generation, or at most 
two generations. This quite precludes evolutionary 
change acting through Mendelian factors. The view 
that some general body-change is involved appears to 
be supported by the fact that local causes will initiate 
the disease in some subjects and not in others. Conse- 
quently we must look to some article of diet or some 
custom of life which can reach and affect the stability 
of the cell. There are obvious difficulties in laying 
the blame for a change so deep-seated on a custom. 
Moreover, we look in vain for any custom at all likely 
to be responsible. When, however, we come to the 
possibilities of diet, we see much less difficulty. 
In view of what has already been stated, it is 
legitimate to pursue the matter yet further, and to 
ask if within recent years we are not taking into 
our bodies more abundantly than formerly some sub- 
stance or substances which might be held responsible 
for the increase of cancer. Many accustomed articles 
W See “Encyclopedia Britannica,” last ed., Art. Cancer. Statistics for 
canc'rin England and Wales (1912) show the highest mortality till then 
recorded. (Daily Mail Venr Book, 1915.) ‘The more recently issued 
s‘atistics for 1913 reyeal a still higher death rate. 
NO. 2380, VOL. 95] 

| 
! 
of diet may, doubtless, contribute in some degree 
towards abnormal cell mitosis and yet be quite harm- 
less under the conditions of consumption. As already 
stated, it is known that alkaline solutions of lactose 
and glucose possess the parallel qualities required for 
affecting the photo-sensitive films. I have not ob- 
tained this action on the ordinary dry plate, nor got 
any latent image with ordinary sugar in alkaline 
solution. Milk, however, gives a faint effect, and this. 
may be due to lactose. Sugar is an article of diet 
the consumption of which has increased in modern 
times, and the evidence for its sensitising activity— 
either directly or indirectly—should not be lost sight 
of as possibly concerned in the cancer problem; 
although it must be regarded as a priori improbable 
that a great natural food would act in this way. 
A more suspicious substance is found in tannin. 
This substance enters, as all know, largely into the 
composition of teas of all varieties to the extent of, 
usually, 11 to 26 per cent.; and 60 to 80 per cent. of 
this is obtained in the normal extract. Tea, as an 
article of diet, has replaced all other beverages in the 
light meals of the day. This especially applies to the 
better-off classes. In former years this beverage was 
only taken at ‘tea-time.”’ The cancer statistics 
when compared with the statistics for the consumption 
of tea in this country show features in common. Both 
curves rapidly rise for several decades preceding the 
last, and within recent years show a somewhat less 
rate of increase.'* 
As regards the consumption of tannin in other 
countries, it is to be remarked that this substance 
enters into coffee to the extent of about 22 per cent., 
and is present in red wines. Obviously without 
statistics both as to the consumption of tannin- 
containing beverages and of the prevalence of cancer 
we cannot discuss the geographical evidence. It is 
stated that in China cancer has long been a prevalent 
disease. In Australia tea is said to be largely con- 
sumed. The cancer death-rate is reported to be as 
large as in Great Britain, and to be increasing. 
Tannin or gallotannic acid is itself a photographic 
sensitiser, and has long been known as such. It 
absorbs the halogens.!® It is the parent substance of 
a complicated and only partially studied group of 
substances in which the reducing properties required 
for development and sensitisation seem to prevail- 
Thus gallic acid, a derivative which does not coagulate 
albumen, and is said to be absorbed in the body by 
administration of tannic acid, is a developer and 
sensitiser. Another derivative is the powerful developer 
pyrogallic acid, which along with gallic acid is stated 
by some writers to be excreted by the kidneys. As 
transported in the circulatory system these substances 
must, of course, acquire neutral or faintly alkaline 
characters. Other substances which possess the re- 
quisite reducing properties, and are constituents of the 
complex tannins, are pyrocatechol and hydroquinone. 
Thein (or caffein) does not appear to exert more 
than a very feeble effect on the film, even when in a 
state of saturated solution, either neutral or distinctly 
alkaline. This substance is stated to be excreted un- 
changed. 
If the increased prevalence of cancer is wholly or in 
part traceable to the increased consumption of tannin, 
we must regard the derivatives of this substance as 
predisposing the cells throughout the body to the inci- 
dence of the disease. The appearance of the disease 
at any particular point in the body is probably deter- 
mined by local stimulus of cancerous mitosis. The 
view suggested is that a general instability or irrit- 
18 Compare figures given for tea-consumption in Thorpe’s ‘‘ Dictionary of 
Applied Chemistry,” art. Zea, with the Cancer Tables in Burns's ‘ Vital 
Statistics Explained.” (London: Constable, 1914.) 
19 Meldola, doc. c7t., p. 98. 
