MICROBIAL DISEASES OF MAN AND ANIMALS. 669 



and loss of flesh. If amoebic dysentery causes death, it usually does so 

 by perforating the bowel and producing a peritonitis, by opening a blood 

 vessel in the intestine and causing a fatal haemorrhage, or by producing an 

 abscess of the liver. Liver abscesses are a not infrequent sequence of 

 amoebic dysentery. 



Amoebic dysentery is cured with difficulty; but, since the encysted 

 amoebae are killed by heat, it can be avoided easily by eating and drinking 

 only foods and liquids that have been cooked. 



ENTERO-HEPATITIS OF TURKEYS. 

 Amoeba meleagridis. 



Entero-hepatitis, or black-head, of turkeys is caused by Amoeba 

 meleagridis. The disease is wide-spread throughout North America. It 

 is a very fatal affection and on many farms it makes the raising of turkeys 

 absolutely impossible. The disease is characterized by thickening and 

 ulceration of the caeca, and by necrosis and abscess of the liver. These 

 lesions are caused by Amoeba meleagridis, a small amoeba measuring 

 about 8/1 to io// in diameter. Turkeys become infected with this parasite 

 by swallowing its encysted forms; young turkeys may become infected 

 from encysted amoebae, which adhere to the shells from which they were 

 hatched. 



There is no treatment for the disease, but it can be avoided through 

 keeping clean stock on land which has never been infected by droppings 

 from infected turkeys, and by carefully wiping eggs intended for hatching 

 with formalin. 



FLAGELLATA. 



The spirochaetes, a treponema, the herpetomonads and the trypanosomes 

 are the most important of the parasitic flagellates. 



SPIROCH.ETA. 



Many spirochaetes are, apparently, harmless parasites in shell fish, in the 

 alimentary canals of some animals and in the blood of fish, birds, and many 

 mammals; other spirochaetes produce disease in men and poultry. 



