In the processes of inflammation leucocytes pass in great numbers through the walls of the capillaries.

The effect of quinine in arresting their movements, when mixed with them directly, naturally leads one to expect that it may arrest their migration from the capillaries, when injected into the blood, and this anticipation has been realised in the experiments of Professor Binz.

To observe this phenomenon the brain of a frog is to be destroyed, and a little curare injected under the skin, in order to abolish any spinal reflex movements. It is then laid on a piece of cork, such as that shown in Fig. 8, with a hole at one side, over which a piece of glass is fastened about half an inch higher, by means of two other pieces of cork and some sealing-wax. On this a piece of sheet cork of the form shown in the figure, and a round piece of glass are cemented so as to form a channel, in which the intestine lies. The body of the frog is fixed to the cork, the abdomen opened, the intestines drawn out, and the mesentery fastened with very fine pins over the aperture. In half an hour, or two hours, the leucocytes pass rapidly through the walls of the capillaries, and afterwards wander through the tissues.

Fig. 8.   Apparatus for examining the mesentery of the frog under the microscope

Fig. 8. - Apparatus for examining the mesentery of the frog under the microscope.

The drug may then be injected into the lymph-sac, or locally applied to the mesentery.

When quinine is applied locally to the mesentery in this condition it arrests the movements of the leucocytes, which have already emerged, but does not prevent those which are still within the vessels from going out; they therefore form a dense accumulation around the vessel (Fig. 9, b). When injected into the circulation, on the contrary, the leucocytes which are in the vessels are prevented from passing from the capillaries, while those which have already passed out continue to wander onwards, and thus a clear space is left outside the vessel (Fig. 9, c).

Fig. 9.   Diagram to illustrate the action of quinine on leucocytes, modified from Binz (Das Wesen der Chininuirkung. Berlin, 1868)

Fig. 9. - Diagram to illustrate the action of quinine on leucocytes, modified from Binz (Das Wesen der Chininuirkung. Berlin, 1868). The thick lines represent the walls of the blood-vessel, and numerous leucocytes are shown both inside it and outside distributed through the adjoining tissues. a represents the vessel before, and b after, the local application of quinine. The leucocytes outside the vessel have their movements arrested, and cannot wander on through the tissues, while those inside are not affected and continue to emigrate. c represents the effect of quinine injected into the circulation or lymph-sac. The leucocytes inside the vessel are here affected first, and their emigration stopped, while those outside still continue to travel onwards.

The quantity of quinine necessary to produce this effect is 1/25000 th to 1/20000th of the animal's weight.

If quinine were given to stop the exit of leucocytes from the vessels in peritonitis, three or four grammes would be required to be given within a short time, to a man weighing 150 lbs.

In guinea-pigs a dose of quinine sufficient to kill the animal does not stop the movements of the leucocytes in its blood, which are seen to go on, when a drop of it is examined after death.