APPENDIX. 351 



they were thought to be vibrios or spirilla. A drop of 

 blood under examination appeared to quiver with life, and 

 on diluting the blood, motile filaments could be seen 

 rushing through the serum, and tossing the blood- 

 corpuscles about in all directions. Under careful exami- 

 nation the filaments were found to consist of a thicker 

 portion or body, with at one end a flagellum (Fig. 129). 

 After fixing with osmic acid they measured O'8 I ^ in 

 width, and 20 30 //, in length ; the flagellum was about 

 as long as the body, so that the total length of the 

 organism was about 50 /x. Lewis detected these parasites 

 in 29 per cent, of the species Mus decumanus and MILS 



FIG. 129. PARASITES IN THE BLOOD OF RATS [after Lewis]. 



rufescens. Though they had many features in common 

 with motile organisms of vegetable origin, they appeared 

 to approach much more closely to the Protozoa, more par- 

 ticularly several of the species of Dujardin's Cercomonas. 



Wittich* discovered, in the blood of hamsters, whip- 

 like bodies with lively movements. They resembled 

 frog's spermatozoa, possessing a thick portion continued 

 into a long lash-like thread. Wittich considered them 

 identical with the organisms described by Lewis, and they 

 also were observed in apparently healthy animals. Koch*f* 

 later met with the same organisms. 



* " Spirillen im Blut von Hamstern," Centralbl. f. Med. Wiss. 

 1881, No. 4. 

 t Mittheilungen aus dem Kaiser lick. Gesundh. Ami. 1881. . 8. 



