THE SLEEPING SICKNESS 



173 



As to the parasite itself the trypanosome a long 

 and very interesting story has now to be told. The first 

 blood-parasite ever made known to naturalists and 

 medical men was that to which Gruby, in 1843, gave the 

 name Trypanosoma sanguinis. He found it in the blood 

 of the common frog. We have here reproduced a figure 



B 



FIG. 49. 



The earliest discovered Trypanosome, described by Gruby in 1843 as 

 " Trypanosoma sanguinis" and found by him in the blood of the common 

 esculent Frog. 



It was not noticed again until it was re-discovered by Lankester in 

 1871, who published the above figure of it in the Quarterly Journal of Micro- 

 scopical Science in that year. 



of this original trypanosome (fig. 49). Similar parasites 

 had been seen, but not named, in the blood of fishes. 

 These trypanosomes are all very minute and of a some- 

 what elongated form, a fair average length being one 

 thousandth of an inch. They are simple protoplasmic 

 animals, consisting of one single nucleated corpuscle. 



