ASCARIS LUMBRICOIDES 



655 



which has an externally irregular coating of albumin, which is 

 stained brownish-yellow by the stercobilin of the faeces. These eggs 

 can stand alteration in temperature and moisture. In warm, moist 

 earth the embryo appears in about a month in the form of a spiral 

 roll, but does not hatch until it reaches the interior of man, when it 

 develops into an adult, as was shown by the experiments of Davaine, 

 Grassi, Calandruccio, Ltitz, and Epstein. 



Leuckart and von Linstow believed that an intermediate host was 

 necessary. Stewart has shown that the larval forms after hatching 

 from the eggs pass into the liver and thence by the blood-stream to 

 the lungs, whence they reach the stomach by migrating up the 

 bronchii and trachea. 



Stiles found that the house-fly could carry the egg, which passed 

 through its alimentary canal unaltered. The worm matures, and 

 deposits ova in one month from entering the body. 



Pathogenicitye — It is only pathogenic in large num.bers, or when 

 it invades the liver, causing abscess, or the appendix, causing 

 appendicitis. The larvae in the lungs apparently cause broncliitic 

 symptoms. 



Animals. — -Monkeys, dogs, and perhaps pigs. 



Ascaris (?) maritima Leuckart, 1876. 



An immature worm, possibly accidentally swallowed in food, was 

 vomited by a child in North Greenland in 1865, and was supposed 

 to be an immature female Ascaris. 



Ascaris (?) texana Smith and Goethe, 1904. 



Stiles appears very doubtful as to whether this worm is an 

 Ascaris. The female only is known, measuring 58 to 60 millimetres 

 in length. Uterine eggs 60 by 40/^. It was found in a man in Texas. 



Toxascaris Leiper, 1907. 



Definition, — ^Ascaridae vvdth the anterior end of the body bent 

 dorsally, cuticle finely striated, oesophagus simple, without a bulbous 

 portion. Palpi of lips club-shaped. Male with a tapering, acicular 

 tail, and without ventral protuberance behind anus. Six pairs of 

 post-anal papillae in two groups, the ventral pairs continuous, with 

 a pre-anal row on each side of the body, and three lateral pairs on 

 the outer aspect of the tail. Testis lies in the anterior part of the 

 posterior half of the body. Seminal vesicle long and tubular. 

 Ejaculatory duct short. Female with vulva about the centre of 

 the body. Egg oval and smooth. 



Species. — Of the species belonging to this genus, only one, 

 Toxascaris canis Werner, 1782, is known in man. 



Toxascaris canis Werner, 1782. 

 Synonyms.^ — -Lumhricus canis Werner, 1782 ; Ascaris canis Gmelin, 

 1789; A. ntarginata Rudolphi, 1802; Toxascaris lirnhata Railliet 

 and Henry, 191 1, 



