520 Sleeping Sickness 



thyroid gland, of the lymph ,nodes and spleen. In some cases 

 meningitis occurs. It is extremely fatal. 



In adults it is apt to take a more chronic course in which the 

 chief symptoms are enlargement of the thyroid gland, and a myx- 

 edematous condition of the skin. The lymph nodes usually en- 

 large. If the adrenal glands become affected, symptoms resembling 

 Addison's disease make their appearance. If the heart muscle be 

 invaded by the parasites, its power is diminished and the pulse 

 becomes feeble and irregular. If the nerve-cells or neuroglia cells 

 of the central nervous system be affected through parasitic inva- 

 sion, symptoms occur according to the extent and localization 

 of the disturbance. There is always irregular fever and marked 

 anemia. 



Chagas found a trypanosome in the peripheral blood of patients 

 suffering from Opilafao, and gave it the name Trypanosoma cruzi. 

 Later studies of the micro-parasite have, however, shown that its 

 method of reproduction differs so strikingly from that of the trypano- 

 somes, that it was necessary to make a generic distinction between 

 the two, and it is now called Schizotrypanum cruzi. 



Morphology .^ — The Schizotrypanum is present in the peripheral 

 circulation only during the febrile stages of the disease, when it 

 may be found by the usual methods of staining for trypanosomes. 

 It is a long slender trypanosome-like organism, with the char- 

 acteristic fusiform shape, with a nucleus, a large blepharoplast, a 

 flagellum and an undulating membrane. No measurements are 

 given, but the parasite is rather small. No dividing forms are 

 observed in the circulating blood. The tr3rpanosomes .may be free, 

 may be attached to the erythrocytes or may be partly or entirely 

 in the red corpuscles. They show sexual dimorphism, the males 

 being long and slender, the females shorter and stouter. 



Reproduction. — Gametogony takes place in the lungs. Such of 

 the trypanosome forms as are caught and retained there, lose the 

 undulating membranes, the two ends curve toward one another 

 forming first a crescent, them unite and form a ring. The female 

 parasites shed the blepharoplasts, and in both male and female 

 parasites the nucleus breaks up into eight secondary nuclei, giving 

 rise to eight merozoits. The merozoits derived from the female 

 parasites have a single nucleus, those derived from the male para- 

 sites, a nucleus and a blepharoplast connected by a fine thread of 

 chromatin. The merozoits thus formed enter into erythrocytes 

 where they eventually develop into the trypanosome forms. Hence 

 is explained the peculiar relation of the trypanosomes to the eryth- 

 rocytes mentioned above. 



The chief multiplication of the parasites, however, takes place in 

 the cells of the voluntary muscles, the heart muscle, the central nerv- 

 ous system, the thyroid, the adrenal glands and the bone marrow. 

 In these situations, according to Chagas, the parasites take on a 



