28 Sir D. Bruce and Capts. Hamerton and Bateman. [Sept. 18, 



shaped like ordinary trypanosomes, with a beak or rostellum at one end, 

 a fairly thick flagellum at the other, and furnished with an undulating 

 membrane, are fairly common. Large irregular masses of any shape, 

 furnished with one or more flagella, are also frequent. 



Contents of Cell. — These cells have a remarkable appearance, as they are 

 filled with highly refractile granules, large in size, round in shape, and 

 numerous. 



Undulating Membrane. — The round, oval, and pear-shaped forms do not 

 appear to possess an undulating membrane, whereas the long, slender forms, 

 as also the huge fish-shaped or octopus-like forms, often show well-marked 

 undulating membranes. 



Flagellum. — The flagella in these living unstained cultural forms are thick 

 and coarse, and differ markedly from the slender structures usually associated 

 in the mind with trypanosomes. Just as in the parasitic forms found in the 

 blood, it is evident that the protoplasm of the body extends to the tip of the 

 flagellum giving rise to this thick stumpy appearance. 



Motion. — The slender forms are active and swim fairly quickly across the 

 field. The large, irregular forms are stationary, but exhibit actively 

 wriggling flagella and amoeboid movements of the body substance. 



Colonics or Aggregates. — Colonies or aggregations of 10 to 20 individual 

 cells are common. The cells are arranged irregularly. Some of their 

 flagella may be directed outwards, while others are seen entangled in the 

 mass and feebly wriggling. On the third day these aggregations may be 

 seen as large as three to five fields of the microscope, and must be composed 

 of many thousands of individual trypanosomes. 



B. Fixed, stained. 



Method of Fixing and Staining. — The cultural forms of Dr. Edington's 

 trypanosorhe were either prepared by mixing a drop of the cultivation fluid 

 with fresh serum, spreading on a slide, and staining by Leishman's modifica- 

 tion of Eomanowsky's method, or the fluid was spread on a slide, fixed by 

 osmic acid and stained by Giemsa, and then treated with orange tannin to 

 differentiate the various structures. 



In Leishman-stained preparations the protoplasm of the cells is stained 

 a pale blue, the nuclei and irregular masses of chromatin reddish or pink, 

 while the vacuoles stand out as unstained spaces with sharply-defined 

 margins. In Giemsa-stained preparations, on the other hand, the protoplasm 

 is stained a pale puce colour, while the chromatin material is stained reddish 

 purple. 



Protoplasm. — The protoplasm of the cell is homogeneous, but contains 



