FLAT WORMS 



haematobium. Catto considers that the S. japonicum may live in both arteries and 

 veins. The other two species only live in branches of the portal vein. The blood 

 flukes are about 1/2 inch (13 mm.) long. All of these flukes live separately until 

 maturity. At this time the female enters what is known as the gynaecophoric canal 

 of the male; this canal is formed by the infolding of the sides of the flat male fluke, 

 thus giving a rounded appearance to the male. The female is longer than the male 

 (about 5/6 of an inch long), and is thread-like and of a darker color. Her two 

 extremities project from the canal of the male in which she lives. 



The oral sucker of the male is infundibuliform and is smaller than the peduncu- 

 lated acetabulum. In the female the oral sucker is larger than the acetabulum. 

 The eggs are fusiform, yellowish in color, have a thin shell and a terminal spine. 



The most prominent symptoms of the Bilharz disease are haemat- 

 uria and bladder irritation; later on calculus formation. In rectal 

 bilharziasis the symptoms are more those of bleeding piles or of a mild 

 dysentery. 



There may also be involvement of the appendix. In the Japanese infection 

 the symptoms point more to liver and spleen, there being ascites, cachexia, and a 

 bloody diarrhoea. 



The eggs of the S. japonicum are readily found in the fasces; they are about 

 100 X 70/4. They are oval, transparent, and with a smooth shell, within which can 

 be made out the outlines of an embryo. Upon adding water the ciliated embryo 

 begins to show movement in about ten minutes and shortly afterward bursts out 

 of the shell and swims about actively. It is more melon-shaped than the miracidium 

 of S. haematobium. 



The life history is not known of any of these flukes. Looss conjectures that it 

 is probable that the miracidium enters the skin, not requiring an intermediary host. 

 Frequent experiments have failed to show any mollusk, etc., which attracted the 

 embryo. Evidence seems to show that those who are constantly wading about in the 

 water of the pools or the mud of the fields are the ones most subjected to infection. 



Katsurada, by experiments with a cat and dog, has proved that infection will 

 take place through the shaved skin of an animal held in infected water none of 

 the water being allowed to enter by mouth. Fully developed miracidia and male 

 and female flukes were found in the portal vein. It is thought that further develop- 

 ment of the miracidia in the body may account for the heavy infection. 



Turner has recently noted the frequency of bilharzial affections of the lungs in 

 South Africa (50% in natives) and he thinks this may be an important factor in 

 prevalence of lung diseases in the natives of this region. He considers bathing in 

 contaminated waters of prime importance in the causation of the infection which 

 he thinks is probably by way of the skin. 



A recent view is that the miracidium enters while bathing by the preputial 

 channel, hence the value of circumcision. 



If urine containing eggs is diluted with water the miracidium breaks out of the 

 shell and swims about as if in search of some desired object. 



The view is also entertained that the miracidium may gain access to the body 

 through the drinking water; there is much evidence against this. However access 



