.30 PROTOZOA AND DISEASE 



and by finding living trypanosomes in the blood. The morbid 

 structural changes found in various organs brain, spinal cord, 

 heart, lymph-glands, etc. were round-cell-infiltration i.e., peri- 

 vascular accumulations of mononuclear leucocytes and clusters of 

 micrococci. The only histological evidence of the presence of 

 protozoa was seen in a haemorrhage in the heart-muscle, where was 

 found a degenerated trypanosome, which would hardly have been 

 known for such without the previous clinical examination. 



Laveran and Mesnil have observed that in dourine 1 and mal de 

 caderas (equine trypanosomoses), as in sleeping sickness, nervous 

 symptoms are marked. In the two former paralysis of the extremities 

 occurs. In these diseases the parasites often appear to be absent 

 from the blood for a period, but if blood apparently free from 

 parasites be injected into another animal (not immune) the disease 

 is thereby communicated. 



It is very important that a close watch should be kept on any 

 promise of success in medical treatment in diseases caused by protozoa. 

 Thomas and Breinl, 2 of the Liverpool School of Tropical Medicine, 

 have found that atoxyl, an arsenic compound, slows the progress of 

 the disease, though as yet it has not been found to prevent its fatal 

 issue. Kopke had a similar experience. With improved methods 

 of administration of the drug complete success is not to be despaired 

 of. Meanwhile the British Government are combating the disease 

 by administrative measures based on the above discoveries. 



Kala-Azar (Black-Fever} or Tropical Splenomegaly. 



Kala-azar is the epidemic manifestation of a fever endemic in 

 extensive areas of India, which has spread slowly up the Assam 

 Valley as a wave of greatly increased mortality, dying out largely 



1 Dourine and mal de caderas are flagellate diseases of horses met with 

 chiefly in North Africa and South America respectively. Dourine has some 

 resemblance to syphilis, especially in the mode of its propagation. A demonstra- 

 tion of the lesions in dourine was given by J. W. Mott before the Pathological 

 Society on May 29, 1906. 



2 For details see the Harben Lectures by Professor P. Ehrlich, Journal of 

 the Royal Institute of Public Health, August, 1907, p. 450. 



