FLAGELLATED ORGANISMS IN THE BLOOD OP ANIMALS. 367 



parasite was seen to swing freely from a to b and from a to c, 

 the free end of the lash presenting a screw-like appearance. 

 Another specimen was watched for half an hour whilst it 

 remained attached to a granular mass in the preparation, but 

 in this instance, as represented at the right half of Fig. 4, the 

 parasite had fixed itself at a point about 3 fx from the end, 

 and to swing itself, as from a to b, from this fixed position. It 

 will be noted that the part of the body by which the parasite 

 attaches itself here corresponds with that represented as having 

 been attached to the red blood-corpuscle in a previous figure. 

 In this instance, also, the lash was observed to manifest incessant 

 screw-like movements, the movement apparently commencing 

 at the tip of the flagellum and proceeding rapidly upwards 

 until the point of attachment to the granular mass was reached, 

 and here it stopped abruptly. 



Many attempts were made to demonstrate the presence of 

 another flagellum at the opposite end, but without any satis- 

 factory result. In preparations made by drying a film of the 

 affected blood on a cover- glass both ends of the parasite are 

 often seen to be very pointed, but in all cases a distinct flagellum 

 could only be made out at one end. When a solution of 

 gentian-violet is added to such a slide the parasites are rapidly 

 stained and present a granular appearance throughout, granules 

 being frequently distinguishable as far as the extreme tip of 

 the flagellum, as may be observed in Fig. 5. Occasionally the 



Fig. 5. — Action of gentian-violet on specimens of the organisms from the 

 blood of a rat. x 1000 diameters. 



flagellum appears to be retracted, as shown in the sketch in the 

 middle of the figure, and I have sometimes thought that such a 



VOL. XXIV. NEW SER. C C 



