?( 19 ) Search for segmenting forms should be made an hour or so before the time of onset of the febrile paroxysm. If one can secure a case of regularly intermittent Quartan fever, very perfect segmenting " daisy like " forms will be easily found in the peripheral blood. The spirillum obermeyeri. The Filaria nocturna. Trypanoso mata. 2.-The examination of specimens of blood for other parasites. The possibility that other parasites than those of malaria may be present in a blood film must always be kept in mind during the examination of the film, and occasionally we should turn our attention away from the careful scrutiny of the red blood corpuscles and concentrate it upon the clear spaces between the corpuscles, focussing upwards and downwards with the fine adjustment especially with a view to ascertain the presence or absence of the spirillar or spirochete organism which is the cause of relapsing fever. (Plate II, g.) This organism is about three times as long as a red blood corpuscle, but it is exceed ingly thin and therefore is not easily detected in stained preparations unless the observer's attention is concentrated upon the attempt. In the examination for this parasite as well as for other parasites which occur free in the blood plasma, such as trypanosomes and embryos of filariæ, it is best to employ in the first place specimens of fresh blood. The fresh film to be examined for the spirochetes of relapsing fever should be taken during a period of pyrexia and examined with a one-sixth inch objective. The movements of the parasites cause a vibratory disturbance of the corpuscles which plainly indicates that a living organism is moving about amongst them. Afterwards dry films should be prepared and stained and examined with the one-twelfth inch objective. The fresh film to be examined for filarial embryos should be taken as late in the even- ing as possible, because as a rule they appear in the peripheral blood at night- time only. The examination should be made with a two-thirds inch objective with which, owing to their comparatively large size, the embryos can be plainly seen violently pushing the corpuscles about in all directions. (Plate II, d.) Trypanosomes (Plate II, f) have not been found in human blood in India up to the present but, they have been found in human blood in Africa where they are the cause of the prolonged and fatal fever called trypanosomal fever and of the deadly disease called sleeping sickness. They occur, however, in many animals in India and one species, Trypanosoma lewisi, can be easily studied in the blood of rats. Another species, Trypanosoma evansi, is the cause of the fatal disease of horses, oxen, mules, camels, etc., named surra. \ill\