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54^ Pathological Significance of Nematode Hcematozoa. [part hi. 



divides into the two uterine tubes delineated in the figure (21 6). These tubes are 

 also filled with ova, each ovum containing a more or less clearly differentiated embryo, 

 especially towards the vaginal end ; but in no part of the genital tract are free embryos 

 to be found. On tracing the course of the uterine tubes by means of a low power 

 until within about a quarter or half an inch of the caudal extremity (Fig. 21 c), they 

 are found to terminate in still smaller tubules (the ovarian) ; and these, after forming 

 numerous coils around and alongside the intestinal tube, terminate abruptly in a caecal 

 manner, retaining pretty much the same diameter throughout their entire course. 



The caudal extremity (Fig. 21 c) of the female is not so complicated as that of 

 the male; it is very slightly pointed, and at its extremity something suggestive of 

 the remnant of a gland, or of the site of exit of the water-vascular system, may frequently 

 be discerned : in the male also a similar appearance may often be detected. 



The ova in the earlier stages are oval, but as the development of the contained 

 embryo advances, the firm, though thin, " shell " becomes more elongated and the ends 

 of the ovum more blunt (Plate XXXVIII, Fig. 5). The ova are about ^ioth of an inch in 

 length and about yeVotli in width. When a ripe ovum is crushed beneath the covering 

 glass a well-developed embryo escapes, which, however, does not manifest any activity 

 (Fig. 6). 



The embryos when thus deprived of their covering vary somewhat in size, the 

 average dimensions of the particular specimens measured were found to be about o^^yth 

 of an inch from end to end and about eoV^th at the widest part— just -^^\h. as broad 

 as long. With reference to these embryos it may be further remarked that the thickish, 

 yellowish fluid in which the mature worms are imbedded may be squeezed through the 

 orifice in the tumour (usually found without difficulty) communicating either with the 

 aorta or the oesophagus, according to its anatomical relations. In this way innumerable 

 ova may be made to pass into either channel, as the fluid is well charged with eggs 

 in all stages of development. 



I have not, however, observed any free embryos in this fluid, nor could I find any 

 along the whole course of the intestinal canal in the dogs examined, where the parasites 

 were lodged in tumours in the oesophageal walls, although plenty of ova, apparently 

 unaltered, could be detected throughout the entire gut.* On one occasion only have 

 I observed ova on a slide of blood containing Hsematozoa : this preparation was obtained 

 by scraping the inner surface of the aorta with the edge of a covering glass. 



It would, therefore, appear that the ova require some considerable time before the 

 escape of the embryo takes place, certainly a longer period than is sufficient for them 

 ' to be conveyed the entire length of the intestinal canal. 



I have made numerous attempts at bringing the embryos to maturity : by means 



of moist earth ; by feeding cockroaches with bread soaked in fluid containing ova ; by 



introducing ova into the stomach and peritoneal cavity of frogs, etc., but have not yet 



succeeded — the ova and their contained embryos being, from a week to a fortnight 



* Bochmius trigonocephalus is the ordinary nematode Entozoon found in the intestines of dogs in India. 



