ANKYLOSTOMES 157 



worm, and that the anaemia was the result of repeated 

 small losses of blood. 



When it was found that the black contents of the 

 alimentary canal of the worm did not consist of blood 

 or of blood corpuscles, it was supposed that the worms 

 lived on the blood plasma, and further that the haemor- 

 rhages which form around the point of attachment of the 

 worm were only a small part of the loss of blood that 

 occurred at these places. 



The anaemia has all the characters of one due to a 

 haemolytic toxin. The red corpuscles are much reduced 

 in number, there are deposits of haemosiderin in the liver 

 and kidneys, as in cases of progressive anaemia due to 

 haemolysis, and of iron in inorganic combination in these 

 organs. 



In the advanced cases of anaemia numerous worms 

 may be present and yet the anaemia very slowly increases, 

 although if the progress of the anaemia were due to 

 numerous minute haemorrhages it should become still 

 more rapid in advanced anaemics. 



In infection with Bothriocephalus latus a similar form of 

 anaemia occurs, though there are no haemorrhages at all. 

 Looss has shown that in the ankylostoma there are 

 cephalic glands, and it is suggested that these possibly 

 secrete a toxic substance. 



The general opinion now held is that a haemolytic toxin 

 formed by the worm in the intestinal canal of man is 

 absorbed into the blood, and that this toxin whilst in the 

 portal circulation causes haemolysis of the red corpuscles. 



The Parasites. The two species of worms considered 

 appear to have the same effect, and in their life-history 

 also closely resemble each other, so that for symptomat- 

 ology, etiology, and .prophylaxis they are of similar 

 importance. 



Ankylostomum diiodenale is found throughout Asia, India 

 and China, in the South of Europe, and in the islands of 

 the Pacific and Indian Oceans, as well as in Tropical and 

 Subtropical America. In many of these countries it may 

 have been introduced by labour from India. 



