Page:Transactions of the Royal Society of Tropical Medicine and Hygiene, volume 2 (3).djvu/19

ON KALA-AZAR 127 which, according to Statham, distinguished the kala- azar parasite taken from the cadaver some time after death, when probably the lowered temperature and the altere conditions in the tissues had promoted the first stages of a development ordinarily undergone in the gut of the invertebrate host.

Dr. Sambon considered that the present tendency to split up diseases and parasites into multitudinous types was in many instances erroneous, and could only lead to greater confusion in a matter already exceedingly complex. He made that statement all the more readily because he had himself followed such lines. Indeed, at the 1905 meeting of the British Medical Association, he had suggested that probably in relapsing fever, owing to its wide geographical distribution and to the different kinds of arthropoda concerned in its transmission in the various zoo-geographical regions, they might be able to distinguish various types of the disease due to different varieties or sub-species of Spiroshaudinnia recurrentis, and now, to his surprise, he found Professor Nuttall and other authorities on protozoa enumerating no less than five different species supposed to give rise to as many separate forms of relapsing fever ! He believed these species to be founded on very doubtful characters, and even doubted whether the majority of them could be looked upon as separate varieties. Eecent observations which he had been able to make whilst studying cer- tain epizootics (diphtheria, pneumonia, tuberculosis, and various other diseases of protozoal or metazoan causa- tion), affecting many different kinds of animals, had convinced him that whilst undoubtedly they would have to add new diseases to those already known, many others, now looked upon as distinct entities, would have to be reunited.