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THE AMERICAN MUSEUM JOURNAL 



of that class of blood parasites which 

 produce in human beings the fatal sleep- 

 ing sickness in those districts of Africa 

 where the tsetse fly abounds. 



Examine under many magnifications 

 these trypanosomes which have been 

 killed and stained with suital)le aniline 



Trypanosome greatly enlarged. It shows a "basic 

 granule," or blepharoplast near the posterior end, a 

 round nucleus set near the middle of the granular body, 

 a vibratile flagellum like a minute whip lash at the head. 

 The Trypanosome feeds upon the liquid plasma of the 

 blood, first reaching the blood through the bite of a flea, 

 tsetse fly or other blood-sucking insect 



dyes and ;s'ou will find a most interesting 

 structure typical of this class of the one- 

 celled animals known as the protozoa. 

 The whip-like projection or flagellum 

 indicates the anterior portion of the 

 animal, which however is capa))lc of 

 moving Ijoth foi-ward and l)ackward. 

 This flagellum, an ever active vibratile 



whip, is a motor organ which runs back 

 like a chord over a clear, more or less 

 transparent, undidating membrane end- 

 ing in a darkly stained granule. This 

 structure technically called the " blephar- 

 oplast" has the function of go^•erning 

 the motility of the organism, while the 

 larger, heavily stained area above — 

 the nucleus — superintends the vegeta- 

 tive activities of the cell. In this vege- 

 tative process our trypanosome appar- 

 ently liAes on the liquid plasma of the 

 blood. The corpuscles are not directly 

 attacked, suffering only physical injury, 

 yet who can predict what poisonous 

 substance the trypanosome may pro- 

 duce which in turn will prove detri- 

 mental to the acti^■ities of one or another 

 tissue of its host. 



That the parasite first reached the 

 blood of this rat by the bite of a flea is 

 most probable, since these blood-suck- 

 ing insects were abundant in its hair 

 and there waiting again to carry the 

 inoculation to another unsuspecting 

 rodent. 



Trypanosomes are widely distril)uted 

 o^'er the whole world, they attack all 

 classes of \-ertebrates and while the great 

 majority ha\e no apparent effect upon 

 their hosts, especially the cold-blooded 

 forms, yet among warm-l)looded ani- 

 mals they are, in certain cases, the most 

 deadly parasites known to science. 

 They are carried from one host to 

 another by the bite of many blood- 

 sucking insects, although cases are 

 recorded where infection has been trans- 

 ferred in a direct way, as through the 

 food, or by immediate contact with the 

 iminjtired skin. 



