366 TIMOTHY RICHARDS LEWIS. 



The different appearances which they presented as watched in 

 such a solution are sketched at Fig. 3 ; from which it will be 

 observed that the organisms present a striking resemblance to 

 the more generally recognised forms of spermatozoa. On the 

 third day the specimens figured were no longer recognisable in 

 the fluid in which they were kept. 



Whilst watching these particular specimens I was further 

 able to satisfy myself that these, like the generality of flagel- 

 lated organisms, moved with the lash in front — that is to say, 

 in the direction indicated by the arrow which is placed along- 

 side of the middle specimen in Fig. 4. Since this period I have 

 frequently observed the same thing in other specimens, though 

 it is scarcely possible to be sure of the direction of the move- 

 ment until after the parasite has become sluggish. Moreover, 

 they may also be observed to move with the thicker end 

 forwards, but only for short distances. 



YiG. 4. — Different methods of attachment to foreign bodies observed in two 

 specimens of the organisms from the blood of a rat. The arrow along the 

 middle figure indicates the direction of progressive movement, x 1000 

 diameters. 



As already remarked, when describing the specimens from the 

 blood of the dog, they seem to attach themselves to surrounding 

 objects by means of some portion of the thicker end. The 

 specimen sketched in the left half of Fig. 4 was observed to 

 remain attached to a granular mass by the extreme point of its 

 thicker end for a considerable time, whilst the remainder of the 



