ILLUSTRATIONS. 



Plate I. 



Scliematic drawings from preparations stained with Giemsa's solution. Magnifica- 

 tion about 1,500 diameters. 



Figs. 1 to 5. Tlie piroplasmata in fi-esh blood smears from the "original calf." 



Fig. 5, p. Form seen in the centrifugated blood. It is not clear what stage in the 

 life cycle of the parasite this form represents. 



Fig. 6. The trypanosoniata in a bouillon culture of the blood. 



Fig. 7. Trypanosoma evansi from a smear of the fresh blood of the calf infected 

 with surra. 



Plate II. 



Schematic drawings of preparations stained with Giemsa's solution of the first 

 pirosomata observed in calves Nos. 1 and 2. Magnification about 

 1,500 diameters. 

 Fig. 1. a, c, e, f, g, and h from blood of the calf No. 1 ; h and d from blood of calf 

 No. 2. 



a. A pirosoma which apparently is endeavoring to enter the red blood cell 

 with its pointed end situated anteriorly; this form was repeatedly 

 observed in stained pi'eparations. 



h. Pirosoma bigeminum, which apparently has entered recently an enlarged 

 metachromatic erythrocyte and which has drawn after it the connect- 

 ing band of protoplasm. Probably on account of the increased resist- 

 ance in the red blood cell the nucleolus has moved to one side and 

 the nucleus to the pointed end. This form was also occasionally 

 observed in calf No. 2. 



c, d, e, f, g, and li. These forms require no explanation. The red blood cells 

 which contain parasites at this stage in their development are dis- 

 tinctly matachromatic ; their shape is no longer round and in many 

 it is irregular. 

 Fig. 2. The piroplasmata in artificial culture media, lying outside of the red 

 blood cells; from calf No. 4. Magnification about 2,000 diameters. 



a. Piroplasma; the earliest free form observed in the blood bouillon; compare 

 with Koch's illustrations: Beitriige zur Entwickelung.sgeschichte der 

 Piroplasmen. Zlsrhr. f. Jlyg. u. Infektionskrankh (1906), 54, Table 

 I. figs. and 7. 



h and c. Ray forms; (■om))aro also with Koch's illustrations; reference as 

 above. Table i, figs. 9 to 14. 



(/.. Forms with chromatin points; compare with Koch's illustrations; reference 

 as above, Table I. 



e. Round form with chromatin ])()ints. 



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