On Nagana, or Tsetse Fly Disease. 117 



These granules are distributed irregularly throughout the body of the 

 parasite ; they do not occur in the membrane or the flagellum. The 

 chromatin spot situated close to the non-flagellated end in the T. san- 

 guinis is not defined in the Nagana Tnjpanosoma. The T. sanguinis also 

 does not stain at all readily even by basic aniline dyes (dahlia, fuchsin, 

 <fec.), whilst that of Tsetse disease is more readily coloured by these 

 reagents. 



5. Examples joined by the poles opposite the flagellum are common 

 at times, but although they suggest perhaps conjugation, we have no 

 evidence that this process does really occur. After prolonged obser- 

 vation no further changes have been noticed in these joined individuals. 



In freshly drawn blood, or in the lymph of lymphatic glands, or in 

 pleural and peritoneal fluid, when the hsematozoa are common, tangles 

 made up of numerous hsematozoa have been observed ; this has been 

 already described by Lewis. The hsematozoa often converge with their 

 non-flagellated ends towards one common point. In lymphatic glands, 

 before the hsematozoa are found in the blood, such tangles may be 

 present in great numbers. 



6. Forms consisting apparently of two individuals joined side by 

 side by their bodies, the flagella being free, have been observed on rare 

 occasions ; from prolonged observation in the living state we have no 

 reason to suppose that these are undergoing longitudinal fission. 

 Especially in kept blood, &c., many of the hsematozoa may present a 

 rhomboid outline whilst still motile. 



In drawn blood or serous fluids the hsematozoa eventually become 

 motionless; this may occur rapidly, for instance in twenty minutes, 

 but generally some motile specimens can be found after two to three 

 days sometimes, indeed, after as long as five or six. When they are 

 abundant, the tangles above noted are formed. Then the bodies of the 

 organisms become rounded, the nuclear bodies becoming more distinct 

 and readily stainable (hsematoxylin or basic aniline dyes). At the same 

 time the vibratile membrane or fin and the flagellum separate, forming 

 a rather rigid filament. Eventually (generally after three to four days) 

 masses of spherules alone remain ; these apparently correspond to the 

 nuclear bodies. In numerous experiments these structures have uni- 

 formly proved to be non-infective, and it must therefore be inferred that 

 if they are not simply degeneration products, they require other con- 

 ditions for their further development than those that are found in warm- 

 blooded animals. All individuals, however, do not pass through these 

 changes ; some, or even all, may simply become non-motile, stiff, and 

 pale, at the same time retaining their form. In numerous attempts at 

 cultivation in normal blood, similar phenomena are observed without 

 any evidence of multiplication. Within a corpse, the blood and organs 

 become non-infective in about twenty-four hours, the changes in the 

 hsematozoa being similar to those just described. 



