The Medical Summary, Jan., 1894.
_DIGESTIVE LEUCOCYTOSIS._
Many investigators, seeking after an explanation of the methods by which
nutritive material is carried from the alimentary tract to the different
tissues and organs of the body, have called attention to the possible
importance of the white corpuscles in the assimilation of food-stuffs,
citing the fact that in a well nourished carnivorous animal there is a
marked production of new cells in the lymph spaces of the intestinal
mucous membrane after the ingestion of food, the extent of said
production being apparently dependent upon the amount of assimilable
elements contained in the food. It has been further supposed that this
increased production of lymph cells is followed by a corresponding
increase in the passage of leucocytes into the blood, mainly on the
ground that only a comparatively few of the cells could have any local
action in aiding the nutrition of the intestinal walls. There has been,
however, a lack of positive proof of these assumptions until Pohl,[2] in
his studies on the absorption and assimilation of food-stuffs, took up
the matter experimentally, and sought to obtain some positive data
bearing on the question. This investigator made a careful study of the
physiological variations in the content of leucocytes in dog’s blood,
using young animals and feeding them only one meal a day. The leucocytes
were counted after Thoma’s method, preliminary experiments showing that
there was very little difference in the number of white cells contained
in a given volume of arterial or venous blood. Thus, in the case of a
fasting animal, blood taken from the jugular vein contained 16,378 white
corpuscles per cubic millimeter, while blood from the carotid artery of
the same side contained 15,449 white cells per cubic millimeter.
Further, from a well-fed animal, whose blood was examined during
digestion, similar results were obtained, _i. e._, 27,036 from the
jugular vein, and 26,866 from the carotid, thus showing that blood from
the capillaries of either veins or arteries would give essentially the
same results.
A single experiment, illustrative of the many reported by Pohl, may be
given here, as showing the marked effect of food upon the number of
white corpuscles in the circulating blood:
Time. Number white corpuscles per cubic millimeter blood.
9 A. M. 8,689
9 A. M. 100 grams meat fed.
10 A. M. 16,685
11 A. M. 17,296
5 P. M. 7,256
Maximal increase, 99 per cent.
About thirty distinct experiments were tried on ten different animals,
with only two or three negative results to fifty positive ones. The
results, taken collectively, plainly indicate that the increase in the
number of leucocytes in the circulating blood, after the ingestion of
food, is very marked, the maximal increase being 146 per cent., while
the average increase amounted to 78 per cent. This, as Pohl states,
would indicate for the total content of blood in an animal an increase
in some cases of 1,000,000,000 of leucocytes. Control experiments showed
that, normally, there were only comparatively small variations in the
content of leucocytes in the blood, from hour to hour, in the absence of
food. It is to be further observed that this marked increase in the
number of white corpuscles in the circulating blood, after the ingestion
of food, usually reaches its maximum in the third hour, _viz._: at a
time when digestion would most probably have reached its height, no
noticeable change being usually observed before the end of the first
hour after the taking of food. Evidently, some transformation-products
of the ingested food must be formed before leucocytosis becomes marked.
The return to the normal number of leucocytes shows no regularity; in
some cases being very gradual, in others quite rapid.
This marked action of food in increasing the number of leucocytes in the
circulating blood, naturally raises the question whether all varieties
of food possess this power, or whether it is limited to some one or more
individual food-stuffs. In attempting to answer this question, Pohl
tried a large number of experiments, the results of which afforded proof
that neither water, salts, fats, carbohydrates, or even meat extracts,
are able to materially affect the number of leucocytes in the blood.
Proteid-containing foods, on the other hand, such as meat, Witte’s
peptone, and gelatin peptone quickly raise the content of white blood
corpuscles to a marked degree. Somewhat noticeable was the result
obtained on feeding wheat bread. This food-stuff, in spite of its fairly
large content of proteid matter, failed to exert any influence on the
number of leucocytes in the blood, and in conformity with this result it
was found that in herbivorous animals there was an utter lack of
anything approaching a digestive leucocytosis, even after protracted
fasting.
In attempting to explain the cause of this increase in the number of
leucocytes in the circulating blood, after the ingestion of proteid
food, we are at once confronted with the possibility of this apparent
increase being relative rather than absolute; as possibly due to a loss
of water from the blood, incidental to the marked outpouring of
digestive juices accompanying digestive proteolosis. For this view,
however, there is very little support. In the first place, the blood
would need to become very much thickened by loss of water to account for
the increased number of leucocytes observed in the experiments.
Furthermore, we know that the outpouring of watery secretions into the
intestine during digestion is accompanied by an absorptive current in
the opposite direction, which would tend to counteract any tendency
towards concentration of the blood, and, indeed, might lead in many
cases to a direct dilution of this fluid. Again, if the increase in the
number of white corpuscles is to be explained in this manner, there
should be a corresponding increase in the number of red blood
corpuscles. As a matter of fact, Pohl’s results show that those
conditions of diet tending to increase the number of white blood
corpuscles are without any noticeable effect on the red corpuscles.
Abstraction of water can not, therefore, be the cause of the large
number of leucocytes contained in the blood after a proteid diet. Much
more plausible is the view that the increase is due to a more rapid
transference of the corpuscles from their point of origin, _viz._: from
the intestine and from the lymph glands of the mesentery, to the blood.
In other words, it seems probable that digestive proteolysis in the
stomach and intestine is followed or accompanied by a rapid production
of new cells in the lymph spaces surrounding the intestine. If this view
is correct, there should be a much larger number of leucocytes in the
blood and lymph flowing from the intestine, in an animal in full
digestion, than in the arterial blood coming to the intestinal tract.
That such is the case is shown by the following experiment taken from
the many reported by Pohl: