110 Messrs. Kanthack, Durham, and Blandford. 



appear in the blood, and, with daily variations, quickly increase in 

 number. The variations are sometimes remarkable ; thus on one day 

 the haematozoa may be extremely numerous, while on the next day 

 they will have become scanty. 



6. Horse. Systematic observations on this animal, as well as on the 

 donkey, have been made by Bruce. In our first horse the latent period 

 was seven days. The first appearance of haematozoa in the blood was 

 followed by a sharp rise of the temperature. After the haematozoa 

 once showed themselves they were generally scanty and often absent 

 (the centrifuge was not used), but an appearance of the haematozoa in 

 the blood was generally followed immediately by a paroxysm of fever. 

 A few days before death, however, the number increased greatly, 

 falling again to zero two days before death and being low at the time 

 of death. 



7. (hdnea-pigs. After a subcutaneous inoculation, a few haematozoa 

 will generally be found in the blood about the fifth to seventh day. 

 They may then again disappear and reappear from time to time, to 

 disappear again after a few days. This alternation may go on for weeks. 

 Then suddenly the haematozoa become numerous and gradually increase, 

 sometimes with irregular variations, till the blood is almost crowded, 

 200,000 500,000 per cubic millimetre being present. The guinea-pigs 

 die, generally without showing any symptoms, except perhaps convul- 

 sive attacks a day or two before death. 



In some cases no hsematozoa have been found in the blood for over 

 six weeks, although it has been examined daily. They then appeared 

 in small numbers, and after remaining scarce for a week or so, suddenly 

 and rapidly increased as the disease approached its fatal termination. It 

 is, however, more common to find a few haematozoa about a week after 

 inoculation, this being followed by a more or less prolonged period of 

 absence. 



In cases where the disease runs a less protracted course, the haema- 

 tozoa become numerous about four weeks after the inoculation, when 

 they are often present in large numbers ; but, as in the case of other 

 animals, the number of haematozoa may be very variable, being almost 

 enormous one day and very considerably less, or even very small, the 

 next. In a case where the guinea-pig had been bled before inoculation 

 the disease ran a rather short course ; haematozoa appeared nine days 

 after the infection, rapidly rising in number to over 128,000 per cubic 

 millimetre, the animal dying after twenty-two days. In a few cases 

 where the lymphatic gland corresponding to the seat of inoculation was 

 examined, haematozoa were found in the gland whilst they were absent 

 in the blood. 



