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170 rapid and easily excited. The cervical glands and the glands of other parts of the body enlarge and may become tender. It may be that only one gland is visibly involved, or there may be a recognizable general polyadenitis, including the abdominal glands. The implicated glands may be very prominent, or they may not be easily felt. In the early stage of the infection they are soft, later they are indurated. Sometimes they, are painless, sometimes distinctly painful and tender, rarely suppurating. This condition of irregular fever, of debility, of polyadenitis, of slight anæmia, may go on for months, or even, in some instances, for years.

There is reason to hope that in a proportion of cases the disease may terminate at this stage. I know and have seen three cases in which after many months of illness the symptoms entirely disappeared, and have been absent for several years, during which the parasite could no longer be found in the blood, whether tested by microscope or by animal injection (two cases). But, considering that the disease may present at various stages periods of quiescence which, in some instances, may be very prolonged, it would be rash to say whether in any instance of apparent recovery we are dealing with a radical cure, or merely with one of these long periods of latency. Experiments and observations by Laveran and others in other forms of trypanosoma infection, as well as cases of the disease in Europeans, justify the belief that occasionally the parasite does die out, either spontaneously or as a result of treatment.

It would appear that in a given area and in a given population there is a tendency for the virulence of the local trypanosome to i decrease with lapse of time. Thus, the trypanosome of Southern Nigeria, where sleeping sickness presumably ms been long endemic, is less virulent and much more amenable to treatment than that of Uganda, where it is of quite recent introduction.

Remarkable features of human as well as of animal trypanosomiasis are the skin affections and the local œdemas. In many of the lower animals