G. H. F. Nuttall 
433 
rounded and degenerated and ultimately disappear from microscopic 
observation. Although the parasites may reappear in small numbers after 
some days their presence is not accompanied by outward symptoms and 
the animals proceed to recovery. Relapses may, however, occasionally 
occur with the reappearance of parasites. Fatal relapses have only been 
observed in two of our dogs. The influence of the treatment upon the 
fever is very marked. Both in dogs and cattle suffering from piroplas- 
mosis,the temperature usually falls rapidly to normal, and coincident with 
the fall in temperature there is a general improvement in the appearance 
of the animals. The effect of the dye appears to be to cut short the 
acute attack and to convert it into a mild, chronic form of the disease, 
which seems to exert no injurious influence upon the animals. In fact, 
the animals may rapidly improve in condition as evidenced by a gain in 
body-weight and in appearance. Having recovered from the acute 
attack the animals harbour the parasites in small numbers for a long 
time and by virtue of the continued presence in their bodies of the 
piroplasms they continue, for a like period of time, to remain resistant 
to reinfection. Whereas the animals cannot be described as “cured” in 
the sense that they are rendered free from parasites, they are rendered 
proof against reinfection; in other words they are “salted.” 
Judging from the immediate effect of the dye upon the parasites and 
upon the symptoms of piroplasmosis both in dogs and cattle and the 
subsequent behaviour of the animals after treatment, I am fully con¬ 
vinced that trypanblue will prove of great value in practice until such 
time as we shall discover an equally efficient remedy not possessing 
the colouring properties of the dye. The fact that trypanblue dyes the 
tissues for a considerable length of time will necessarily militate to 
some extent against its usage in cases where cattle are intended for 
meat-consumption, but it will assuredly protect valuable breeding 
animals which it is proposed to introduce into a country where piro¬ 
plasmosis prevails. In the case of dogs, this objection will scarcely 
weigh in the balance as against saving the animal from a disease which is 
so commonly fatal. That the colouration of the tissues disappears with 
time is clear from the case of Dog 6 (see p. 422) which was killed on 
the 236th day after the dye was injected and found to be quite normal 
in appearance. Only further observations can determine how long the 
colouration of the tissues lasts in cattle and dogs and it would be well 
if different observers recorded their experiences in this particular. 
At present there exists, to my knowledge, no other remedjr which 
will cure piroplasmosis in either cattle or dogs. 
