364 TIMOTHY RICHARDS LEWIS. 



portion of the parasite, thougli it was frequently observed to 

 present a ribbon-like appearance. 



Shortly after this the puppy got the " distemper," and was 

 struck by one of the native servants, so that it lost the sight of 

 the right eye. On the 15th January, 1881, several specimens 

 of blood from its ear were examined, but not a single parasite 

 could be detected. Further examinations were made on the 

 12th and 28th February, and again on the 24th March, but 

 not a single specimen was found. The dates have been care- 

 fully recorded, as they may be of use to future observers ; and 

 the notes of observations in this instance have been made to 

 subserve the double object of illustrating the more salient 

 points in the microscopy of the parasite, and to give the exact 

 history of this form of parasitism in the dog during a period 

 of from four to five months. 



There are, however, a few other points in connection with 

 the microscooy of these organisms which it seems desirable to 

 refer to as they may be of assistance to systematic writers in 

 deciding their precise position in the animal (or, as some 

 authorities may perhaps consider, vegetable) kingdom. 



These supplementary details will be based on further ob- 

 servations which have been made from time to time, as oppor- 

 tunities offered, during the last three or four years, on the 

 blood of rats, but more particularly on a series which were 

 conducted for purposes of comparison whilst the organisms in 

 the dog were being watched. 



On January 30th, 1881, the following entry is made in my 

 note-book : Examined the blood of five rats, and found flagel- 

 lated organisms in two of them. One of the latter was a 

 pregnant female, but this one, however, did not contain many 

 specimens of the parasite, and none were found in the blood of 

 its young. The blood of the other rat swarmed with the 

 organisms. 



As it had been found that the parasites were remarkably well 

 preserved in a 0*75 per cent, solution of salt and water, half a 

 Pravaz-syringeful of a mixture of the blood of this rat, and of 

 the salt solution — one part to three — was injected into the 



