The White Rat and Sleeping Sickness 



Bv 11. \V. TOWER ami C. F. HERM 



THE t'ollowint; observation made in 

 tlic physiological laboratory of 

 tlie American Museum has gen- 

 eral interest because of its connection 

 with that (lire disease of man, sleeping 

 sickness. A domestic white rat, one of 

 the kind .so fre(|uently kept as a pet, was 

 brought to our laboratory a few days 

 ago with a statement from the owner 

 that the small creature seemed to be sick. 

 I'nder obser\ation he l)ecame less active 

 each day, sitting continually in a sleepy 

 attitude as if dazed and utterly oblivious 

 to the excitement or turmoil in his 

 neighborhood. Occasionally he would 

 waken to eat or would change his posi- 

 tion in a lackadaisical manner if physi- 

 cally disturbed. Af- 

 ter a few days of 

 increasing drowsi- 

 ness an endless sleep 

 overtook him. ,^ 



We were asked to 

 explain the malady 

 which killed the rat 

 and among the \'a- 

 rious examinations 

 that were made, a 

 drop of lilood was 

 observed imder the 

 microscope. The an- 

 swer was there, for 

 besides the usual red 

 and white cells in 

 the blood plasma, 

 there were myriads 

 of minute animals 

 many times longer 

 than broad, lashing 

 their way around, 

 hurrying here and 

 there, pushing aside 

 the white cells and 



piling up the red ones until they re- 

 sembled rows of pennies standing side 

 by side. Such battling! Like schrapnel 

 from an exploding shell! How could 

 any living cell withstand such an ordeal? 

 What must be the nature of these wild, 

 wiggling, microscopical creatures? To 

 the novice they would appear like tiny 

 eels escaping from a foe. Their activity 

 is indeed so vivacious that it is scarcely 

 possible to make out the structure of the 

 organism. Close observation reveals the 

 form and appearance of a "trypano- 

 some," a name which itself means a 

 "l)oring body" and rather uniquely de- 

 scribes one component of their mode of 

 propulsion. They are a representative 



View of u (Iroj) of blood under the microscope, showing normal blood con- 

 stituents and, in addition, many minute parasitic animals which continually lash 

 their way through the plasma. These are the parasites which in man produce 

 the fatal sleeping sickness so dreaded in certain districts of Africa 



249 



