574 



TREMATODA 



In 1880 Baelz found in the sputum of cases of haemoptysis bodies 

 which he took to be psorosperms, and therefore called the disease 

 gregarinosis pulmonum, but when these were referred to Leuckart 

 he said that they were eggs of a Distomum. In the same year 

 Manson found what he took to be eggs of some parasite in a case 

 of haemoptysis, in a Chinaman from Northern Formosa, and later 

 he saw a Portuguese with haemoptysis and obscure thoracic symp- 

 toms, who lived in Tamsui in North Formosa. 



This man died in Formosa, and Dr. Ringer, who performed the 

 post-mortem, discovered in the lungs a minute, fleshy, slightly 

 flattened, oval body, grey in colour, and about a quarter of an inch 

 in length, which expelled some brownish material from a minute 

 orifice near one end. 



This specimen was sent to Manson, who noted the same eggs as he 

 had found in the Chinaman already mentioned, and then forwarded 

 the parasite to Cobbold, who, rightly thinking it new to science, 

 named it Distomum ringeri, the name now in use. In 1883 Baelz, 

 having found specimens in the lungs, named it D. pulmonale. In 

 1890 Otani and Yamagiwa proved that it could occur in other parts 

 of the body besides the lungs by finding it in the brain, where it 

 produced symptoms of Jacksonian epilepsy. Stiles and Looss defined 

 its zoological position; Ward found it in cats, Railliet in dogs, and 

 Stiles in hogs ; while the best description of the lesions caused by 

 it is that by Musgrave in 1907, who found it in the Philippine 

 Islands. 



It is very common in Japan, and is found in China, Korea, and 

 North America, a human case being reported from Mexico by 

 Naunyn. 



In 1908 Ward found P. kellicotti in pigs, dogs, and cats in North 

 America. 



Morphology. — The parasite varies from a reddish-brown to a light slate 

 colour when first removed from the body, but soon becomes greyish on 

 exposure to the air. In shape it is oval, with a somewhat flattened ventral 

 surface, and is capable of slight alterations of its appearance by protruding 

 and retracting its head, and by altering its ventral sucker so that it may appear 

 terminal. The cuticle is covered with scale-like spines, which may be capable 

 of being moved. The oral sucker is spherical and terminal, 0*63 to 0*97 

 millimetre in diameter. The ventral sucker is situated in the anterior half 

 of the body, and is 0*76 to i'3i millimetres in diameter. The oesophagus is 

 short, and divides into the two wavy caeca. The genital pore may be in- 

 distinct, and is always small, lying close to and behind the ventral sucker. 

 The testes lie about, but not quite on, the same level on each side of the median 

 line just behind the uterus. There is neither a cirrus nor a cirrus pouch. The 

 ovary is opposite and slightly posterior to the uterus, which is visible just 

 posterior to the ventral sucker. The yolk glands lie at the sides, and their 

 branches almost meet dorsally, while ventrally they only extend to the 

 intestinal caeca. Laurer's canal is present. The eggs are oval in shape, of 

 a reddish-brown to a light yellow in colour, with a length from 0*08 to o-i milli- 

 metre, and a breadth from 0-052 to 0*075 millimetre. They possess an oper- 

 culum, and contain the ovum and yolk cells. 



The excretory vesicle is well developed, and extends from the pharynx 

 backwards. 



