When, in 1872, I published my lectures on helminthology, I remarked that it was not improbable that, ere long, many more cases of Bilharzia disease would be brought to light. What has been added in this respect is chiefly due to the researches of Sonsino, but a case of some interest has been recorded comparatively recently by Dr W. K. Hatch, stationed at Bombay. From the particulars furnished it seems evident that the victim, an English gentleman, contracted the disease by drinking water, either in Arabia or in Egypt, in which latter country, however, he had only sojourned fifteen days. From the patient’s statements it appears that, hæmaturia is frequent amongst the Arabs. Incidentally, Dr Hatch mentions that Dr Vandyke Carter had informed him that, so early as the year 1862, he (Dr Carter) had detected the embryos of Bilharzia in the urine of an African boy admitted to the Jamsetjee Jejeebhoy Hospital. The treatment employed by Dr Hatch was that recommended by Dr Harley in his well-known memoir. Having myself energetically opposed Dr Harley’s views on pathological grounds, I am not surprised to see it stated that Dr Harley’s method of treatment effected “no diminution in the number of the parasites.” As I said in my lectures (now out of print) it is evident that “nature” in view of moderating the hæmaturia--by the formation of plugs at the ulcerated points of the mucous surface--sets up the artificial barriers above referred to; therefore if you catheterise and employ medicated injections you do more harm than good. As to the administration of belladonna internally, in view of retarding development, or of destroying the parasite, no good can be expected from this source. I certainly obtained better results with buchu and bearberry (_Arctostaphylos_). In the matter of sanitation it is quite evident, from the foregoing data, that the danger of infection cannot arise from the drinking of impure water, as ordinarily understood. The embryonal larvæ would be killed by an admixture of sewage. It is obvious that infection can only occur from swallowing free cercariæ or freshwater mollusks which contain the higher larval forms in their encysted or pupa condition. Slow running streams or stagnant pools with sedgy banks are eminently favorable to the existence and multiplication of intermediary bearers, and consequently their waters are dangerous if employed for drinking purposes.