Now Kurloff in the course of extremely careful and laborious researches, estimated the total number of leucocytes, and then from the percentage numbers, the total quantity of pseudoeosinophil, neutrophil, eosinophil, vacuole containing cells, and lymphocytes, and could thus demonstrate that in uncomplicated cases of removal of the spleen, where inflammatory processes, accompanied by an increase of the polynuclear neutrophil corpuscles, were avoided, a =gradual increase of the lymphocytes= alone in course of time results. This may be a two- or threefold increase, whereas the numbers of all other elements remain unchanged. Kurloff obtained his figures as follows: first he estimated the relative proportion of the different kinds of white blood corpuscles one to another in a large number of cells (500 to 1000). A count of this kind however gives no evidence as to whether one or other kind of cell is absolutely increased or diminished. A fall in the percentage of the lymph cells may be brought about by two quite different factors: (1) by a diminished production of lymphocytes, (2) by an increased influx of polynuclear forms, which naturally lowers the relative count of the lymphocytes. It was therefore necessary to obtain a method which would show alterations in the absolute number of the individual forms of leucocytes. Kurloff used for this purpose the "comparative field"; that is, he counted by the aid of a moveable stage the different forms which lay on a definite area (22 sq. mm.) of the dried blood preparation. This procedure gave very exact results, as only faultlessly prepared, and regularly spread preparations were used. The following figures (from Exp. II.) illustrate the method and its results: April 12 52% pseudo-eos. 10% lymphocytes counted. Sept. 2 (one month after the operation) 22% " 53% " " By the aid of the comparative surface, these figures were supplemented by the following averages. On each surface used for comparison were found: April 12 38 white = 19.8 pseudo-eos. 10.6 lymphocytes. Sept. 2 81 " 18.0 " 46.9 " From this example it follows without doubt, that the =total number of the white blood corpuscles had about doubled itself=, but that in this increase the lymphocytes exclusively were concerned, and the pseudo-eosinophil cells had not undergone the smallest increase. The results which Kurloff obtained by means of this method in animals whose spleens had been removed, may be illustrated by one of his original researches and its accompanying chart and table. Exp. I. Young female, weight 234 gr. Number of red corpuscles in a cubic millimeter of blood 5,780,000. Number of white 10,700. On April 19, 1888, the spleen was removed, the wound healed by first intention. The results of the further investigation of the blood are found in the following table.