360 TIMOTHY EIOHARDS LEWIS. 



blood of hamsters in Germany.^ Wittich's experience coincided 

 with my own as regards their being found in the blood of 

 apparently perfectly healthy animals^ though Dr. Robert Koch,^ 

 instigated by the result of Wittich's observations, found that 

 the hamsters which he procured died, one within two days of 

 being in captivity, and four others subsequently. It does not 

 appear that the blood of these hamsters was examined during 

 life, but after death it was found, in each case, to contain the 

 organisms in question. No reference is made to the examina- 

 tion of other hamsters, so that it is not quite clear whether the 

 animals died as a result of captivity or in consequence of the 

 parasitism. As regards rats thus affected I have had them 

 kept in a cage for weeks, and to all appearances in a state of 

 perfect health. Both Wittich and Koch suggest that the para- 

 sites found by them in the blood of hamsters are in all proba- 

 bility identical with those found by me in rats in India; and 

 Koch gives two micro-photographs of them which correspond 

 very closely with the micro-photographs which were published 

 by me in the above-mentioned Indian ' Sanitary Report.' 



What these organisms are and whence their origin is by no 

 means clear, and as the suggestions which have been offered 

 by various authorities regarding these points are so greatly at 

 variance it seems highly desirable that every detail which can 

 be collected concerning them should be placed on record. 

 This is all the more to be desired, seeing that the question has 

 arisen of their possible influence as a cause of disease. 



I had every opportunity of satisfying myself that the parasite 

 found by Dr. Evans in the dog is identical with that in the rat, 

 as Dr. Evans brought the puppy to Simla in October, 1880, 

 and very kindly made it over to me for observation. The 

 accompanying sketch represents some of the forms assumed by 

 these organisms as observed under a Prazmowski's 1*5 mm. 

 immersion objective. This, together with the following remarks 

 made at the time, are copied from my note-book : 



A drop of blood having been obtained from the puppy's ear 



^ ' Centralblatt fur die medicin. Wissenscb.,' vol. xiXj No. 4. 



* ' Mittbeilungen aus deni Kaiserlicben Gesundbeitsamte/ vol. i, p. 9, 1881. 



