5U2 



THE TICK FKVM'. PARASITK, 



found the horse unaffected, while sheep developed high fever as- 

 the result of intravenous inoculation with virulent blood. The 

 small niaiginal bodies were found in the blood of one of the 

 sheep which was slaughtered, but there were no characteristic 

 apiosoma. The sheep diseases carceag (Babes) and parasitic 

 ictf'ro-haeniaturia (Bonome) are caused, if not by the same para- 

 site, by an ally so close that it seems only a modification. Babes 

 does not describe the parasite at all fully, but since he claims 

 that his di.sease and that of Bonome are identical, it will be 

 sufficient to describe the parasite of the latter (7). The infected 

 blood corpuscles have on their margin or inside round, oval or pear- 

 shaped, strong, light-refracting, colourless bodies, varying in size 

 from 1 to3/x; they frequently show active contracting movements. 

 In the plasma they are seen either singl}- or in twos or threes. 

 The}' are easil}^ coloured by aniline stains. Organs of locomotion 

 were never observed. The blood of the organs contained a greater 

 number of invaded corpuscles than were to be found in the 

 circulating l>lood. In the former places the parasites were chiefly 

 the more mature forms, and in the latter chiefly the younger. In 

 the urine the parasite was found partly free and partly in blood 

 corjjuscles. 



It is admitted bv American and Australian investigators that 

 the cattle tick is the infecting agent. European authors must be 

 aware of the part plaj^ed by the tick in America, and yet no 

 mention of the insect is made in some of their papers. Babes, 

 however, noted that animals suffering from haemoglobinuria were 

 infested with ticks; and Schneidemiihl supplements this, saying 

 that the parasite of this fever exists for some time in the body 

 cavities of the tick as in Texas fever; all ticks do not conve}' the 

 disease, since susceptible cattle may ha\ e ticks without any sign 

 of illness. There are, howe^'er, varieties of ticks, some of which 

 apparently never produce Texas fever, while others do. But of 

 the dangerous species of tick only those that carry infection are 

 to be feared, and this infectivity is determined by locality. It is 

 self-evident that in a new locality the disease must have begun 

 either with an animal or with a tick; in the latter case the. tick 



