THE HAEMOFLAGELLATES 



Central Africa. The earlier stages of the disease, when the parasites are 

 confined to the blood, are known as Trypanosoma-k\er ; the later ones, after 

 the organisms have penetrated into the cerebro-spinal canal, constitute the 

 deadly malady of sleeping-sickness. The true, natural host is unknown. 

 T. equinum, Voges (Syn. T. elmassiani, Lign.). Length 22-25 p, width 

 1^-2 /j.. Distinguished from all other forms by the minute size of the 

 kinetonucleus (Fig. 32, B). Hydrochoerus capybara is almost certainly a 

 natural host. Other well-known lethal parasites are : T. evansi (Steel), of 

 Surra in horses in Indo-Burmah (Fig. 32, c) ; T. eqiiiperdum, Doflein (Syn. 

 T. rouyeti, Lav.), the cause of Dourine in horses, transmitted naturally by 

 coitus (Fig. 32, D) ; T. theileri, Laveran, a very large form, often surpassing 

 50 p. in length, which causes "bile-sickness" of cattle in the Transvaal 

 (T. transvaaliense, Lav., with the kinetonucleus near the middle of the 



FIG. 34. 



T. johnstoni. g, deeply-staining granule at 

 distal extremity of flagellar border, x 1500. 

 (After Dutton and Todd.) 



Fl - 35. 



A Trypanosome from Sene- 

 gambian birds, x 150C. (After 

 D. and T.) 



body (Fig. 33, C-E), has been shown to 

 be, in all probability, only a phase of 

 T. theileri) ; and T. dimorphon, Dutt. 

 and Todd, which gives rise to a trypano- 

 somosis of horses in Senegambia. 



(6) Parasitic in birds. T. avium, 

 Danil., Lav. emend., probably the form 

 to which Danilewsky's original investi- 

 gations related, occurring in owls and, 

 according to Novy and M'Neal, in 

 various other birds. Length 35-45 />t 

 (Fig. 7, F). T. johnstoni, Dutt. and 



Todd. Length 36-38 //., width 1^- p.. 

 TVn -nnrnsitp in <5O lpnrlpr i<5 'iltnnst- 



llns parasite is so i as almost 



to justify the description spirochaeti- 



form (Fig. 34). From Estrelda. The opposite extreme of form is 



seen in a Trypanosome, T. hannae, Pittaluga, originally described by 



Hanna (25) from an Indian pigeon (Fig. 7, o) ; this is relatively 



very broad, and has, moreover, a long, attenuated aflagellar extremity, the 



latter character being not unusual in bird-Trypanosomes. On the other 



FIG. 30. 



T. paddae. At x the base of the flagel- 

 lum is thickened prior to division. 

 X 1200. (After Thiroux.) 



