o
be observed. Thus Weiss found an important increase of the white blood
corpuscles in simple catarrh of the stomach and intestines, which
presented the main features of a lymphocytosis.

Whooping-cough, according to the recent observations of Meunier, also
belongs to the small number of diseases which are accompanied by a
pronounced lymphaemia. In the convulsive period of this disease both the
polynuclear cells and the lymphocytes are increased, the latter in
preponderating amount. The former cells are increased to twice, the
lymph cells to four times their normal amount. Doubtless in these cases
also the lymphocytosis is due to the stimulation and swelling of the
tracheobronchial glands.

An increase of the lymphocytes from chemical stimuli is exceedingly
rare, though, as is well known, a large number of substances (bacterial
products, proteins, nucleins, organic extracts, and so forth) can call
forth a polynuclear leucocytosis. In quite isolated cases, an increase
of the lymphocytes in the blood in consequence of the injection of
tuberculin into tuberculous individuals has been seen. (E. Grawitz.)
From the rarity of these cases it can scarcely be doubted that here a
tuberculous disease of the glands also plays a part, so that the
increased immigration of lymphocytes is brought about not by a chemical
property of the tuberculin but by the extensive specific reaction of the
diseased glands.

Only one single substance has so far been mentioned in the literature as
capable in itself of producing a lymphocytosis. Waldstein asserts that
he has produced by injection of pilocarpine, a lymphaemia which undergoes
a progressive increase with a rise in number of the injections.

The origin also of lymphocytosis is therefore sharply marked off from
that of the ordinary leucocytosis, which consists in an increase of the
neutrophil elements. Whilst the latter is admittedly the expression of
chemiotactic action, and arises by action at a distance of soluble
substances on the bone-marrow, lymphocytosis is due to a local
stimulation of certain glandular areas. Thus in the leucocytosis of
digestion, of intestinal diseases of children, we refer it to the
excitation of the lymphatic apparatus of the intestine, in tuberculin
lymphaemia we recognise mainly a reaction of the diseased lymph glands.
Hence we conclude that a lymphocytosis appears when a raised lymph
circulation occurs in a more or less extended area of lymphatic glands,
a