In the July number of the journal Drs. Dods Brown and Ross give an account of the various methods which have been used to produce an increase in the number of leucocytes in the blood. These methods are numerous and varied, but they do not include one which was discovered accidentally in the treatment of the case about to be described, nor have I been able to find any reference to a similar case in the literature. Various drugs such as nucleic acid, ceredin and argentum colloidale have proved efficacious, and Dr. Lewis Bruce has stimulated the leucocytes by the injection of such an irritant as turpentine. In the present case, however, the simple intra-venous injection of normal saline solution, containing no drug whatever, was found to produce a marked leucocytosis, which in one instance reached the high figure of 28,000. For permission to publish the notes of this case I am much indebted to the kindness of Dr. T. C. Mackenzie.