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are very marked. Relapsing Fever of man is a rather rare disorder and is described
as occurring in direct and immediate association with such debilitating influences as
famines and imperfect nutrition. The blood contains spirilla, which, as Murchison
(Path. Trans., 1875, p. 317,) points out, disappear from the blood before the crisis,
are absent during the intermissions and re-appear with the relapse, phenomena exactly
corresponding to those noted in the mules' disease. Vandyke Carter of Bombay has
conveyed relapsing fever from man to monkeys by inoculation with but six failures
in twenty-one trials (Med. Chir. Trans., 1880, p. 125). It has been observed that
men suffer more than women (3 : 2), whereas I find that females are most liable, but
not markedly so. It is most common in adolescence and early manhood, but the mule
disease seems to affect animals of all ages indiscriminately. The disease of man is
attributed to the following as the principal causes : scarcity of food, overcrowding, want
of cleanliness, and contagion. I could obtain no evidence of the latter, and with regard
to the former, some of my mules which died were fat; none of them are specially crowded,
and their lives and persons are kept decidedly cleaner than those of the average
mule. The blood, in addition to the parasites, has been noted as containing " large,
colorless transparent cells," often two to four times as large as the white corpsuscles ;
these I have generally noted at a certain stage of the fever in the mules as " gelatinoid,
decolorised, red corpuscles," which sufficiently expresses my views as to their nature.
It seems strange to me to read in accounts of the human disease of " even a fourth
relapse," whereas in the mule we get even a seventeenth in some cases; also the low
mortality in man is in striking contrast with the invariably fatal result in equine
patients. Season has little effect although the disease' of man prevails most in winter.
Relapsing fever also occurs to an extent in mules at all seasons, and specially attracts
attention as an enzootic in winter and late autumn. The spirillum of man (Spirochæte
Obermeieri) seems larger, more uniform in diameter, more markedly spiral, and less
ferocious than that of the mule, which I had termed Spirochæte Evansi after its
discoverer, but I find that he is not willing to accept the view that it is a spiral
bacterium, a matter which I shall have to enter into detail about later on. I may
here remark that I have never studied Relapsing Fever of man or its organism
practically, and that I am in the main indebted to Quain's Dictionary of Medicine for
the above facts about them, the articles being by Grimshaw and Bastian. Fever has
not been specially prevalent among the transport drivers who live in lofts above the
mules, nor have any cases of apparent communication of the disease from the mules
to men constantly handling them occurred. I have tried inoculation of a monkey
with marked success. Thus we are in a position to compare the human and mule
disease on a common ground by contrasting Carter's cases of monkey disease with mine.
9. Manifestly it is not possible to verify by experiment its communicability to man,
for the disease conveyed by inoculation might prove fatal after causing much disturb-
ance to the system occurring in paroxysms extending over a long time. The follow-
ing circumstances, trivial in themselves, may be alluded to as possibly links in the chain
of evidence on this point. Veterinary Surgeon (First-class) Frost; when attending mules
affected with this disorder, became ill; he suffered from pain in the left side and used to
say he had caught ulceration of the stomach from the mules ; he recovered only when
he went away to district work. I also, on arrival and having attended the mules for
a short time, had pain in my left side, which especially rendered laughing acutely
painful; this, with an accompanying constant hunger, persisted until my trip to Tonghoo.
I was examined by a doctor because I suspected pleurisy, but none was present.
Subsequently, when collecting specimens of blood from one of the affected animals,
I made a minute puncture accidentally on my hand ; in a few days it became a star-
shaped congested spot and later some fluid collected beneath the epidermis, but these
phenomena ceased after remarkably resembling unsuccessful inoculation of an insus-
ceptible subject. My monkey bit me on one occasion. The wound suppurated freely
for several days, but has now healed, and I feel no ill effects from the accident. We
may conclude that the British Burma disease is of the same class of disorders as "Famine
Fever " of man, and that they are probably not exact pathological equivalents, although
we require more evidence on this point.
10. In the class " Relapsing Fevers " we must also include those which have been
observed and induced by Drs. Vandyke Carter and Evans and myself. Monkeys have