138 . TROPICAL MEDICINE AND HYGIENE 



In this condition, which is the most common termina- 

 tion of the disease, the patient passes into a peculiarly 

 lethargic state, so that while the total amount of sleep 

 obtained may be little above normal he is always drowsy, 

 and frequently falls asleep even at meals or when in the 

 act of performing some ordinary occupation. Before the 

 onset of these symptoms there is usually marked fine 

 tremor and dull headache. The temper is frequently un- 

 certain, and there may be mental irritability. This irrita- 

 bility, as the disease progresses, becomes more marked 

 and mental deficiency occurs. There is a general aspect 

 of misery about the patient and he is apt to be neglectful 

 of his person, and dirty and careless in his habits. 



Muscular weakness is extreme, and unless the patient 

 is regularly fed he rapidly emaciates and dies, partly of 

 starvation. Even when well fed and carefully nursed 

 there is rapidly progressive emaciation. The termination 

 of the disease may be associated with diarrhoea, or the 

 patient may die comatose. 



Varieties. The disease, as it appears in Rhodesia, runs 

 a more rapid and severe course. All know r n cases have 

 been fatal. The parasite in man appears to be morpho- 

 logically identical, but in rats a varying proportion of 

 distorted forms, in which the nucleus is more posterior 

 than in the ordinary forms and may even be posterior to 

 the micro-nucleus, are found. The trypanosomes are 

 more virulent and more readily infective to experimental 

 animals. Stephens and Fantham describe this trypano- 

 some as a distinct species under the name of T. rhodc- 

 siense. Whether the difference is specific, or whether it 

 is a virulent strain modified by passage through different 

 mammalian hosts, and with a different species of Glos- 

 sina, G. morsitans, as a carrier, is not conclusively proved. 

 A further difficulty is that in some strains isolated from 

 cattle similar irregular forms are found, and Bruce con- 

 tends that T. rhodesiense is really T. brucei, the cause of 

 Nagana. As in other strains no such forms have been 

 found, others consider that in some parts of Africa two 



