DIFFERENTIAL COUNT. Lymphocytes 34 = 4,490 Large mononuclears 3 = 400 Polymorphonuclears 61·5 = 8,120 Eosinophiles ·1 = 130 Mast cells ·5 = 66 Chalmers Watson some years previously investigated the blood in cases of _acute gouty polyarthritis_ both during an exacerbation and in the _inter-paroxysmal_ period. His findings were as follows:— During the _attack_ the films showed very marked _leucocytosis_. Also there was present a large number of peculiar myelocyte-like cells, these more than half as numerous as the ordinary finely granular oxyphil leucocytes. “Each of these cells contained a large oval or horse-shaped nucleus, poor in chromatin. The nucleus occupied about half of the total area of the cell. It did not stain uniformly, and it was usually situated to one side, coming right up to the cell outline, and occupying from a third to a half of the total circumference. In many of these cells the nucleus was almost round, with but one slight indentation; in others the indentation was pronounced. The whole cell stained a pale blue, presented a degenerated appearance, and contrasted markedly with the ordinary leucocyte seen in the same film, with its brilliant blue nucleus and bright red eosinophil granules. The special cells under description were also remarkable for their size, measuring about 15 m. in diameter, a few being smaller, about 10 m. Some of them contained vacuoles in the cytoplasm. The general appearance of these cells suggested exhaustion in so far as the cytoplasm did not contain the typical fine oxyphil granules characteristic of the myelocyte. From the character of the nucleus and cytoplasm, they were undoubtedly distinct from lymphocytes. The large lymphocytes were scarce; small lymphocytes were numerous. True eosinophil cells were also scarce. The main bulk of the leucocytes consisted of the ordinary finely granular oxyphil leucocytes and the peculiar myelocyte cells described. “_Blood plates._—Some of the blood-plates were large (4 m. in diameter), and often formed very irregular torn-looking masses. The red cells were apparently normal.” Shortly after Chalmers Watson, Bain published his results of blood examination in _acute gouty polyarthritis_. He also noted the presence of a distinct _leucocytosis_. A differential count disclosed a marked increase of the eosinophil cells, and he adds: “There was present a moderate number of the peculiar myelocyte-like cells originally described by Chalmers Watson.” Dr. Munro, though he carefully examined the gouty blood films to this end, was unable to identify the myelocyte-like cells noted by these observers.