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



When, however, the ova or liberated embryos of the Filaria sanguinolenta find their 

 way into a " host " or other medium suitable for their development during the larval 

 stage — a stage in their development carried on, possibly, to the extent of providing the 

 embryo with some kind of oral armature and a differentiated intestinal tube. Having 

 acquired this stage of growth, the further progress of the parasite is probably dependent 

 on its being swallowed by some such animal as the dog, to the mucous lining of whose 

 oesophagus it attaches itself, then penetrating the muscular tissue of this tube and 

 remaining there or working its way still further till it reaches the tissues of the thoracic 

 aorta, or some other place suitable to its growth and development ; the various stages 

 of which, when the aorta has been selected, have been described on a previous page. 



With reference to the morbid phenomena indicating the presence of these para- 

 sites in the vascular system of dogs during life, I have no definite knowledge. Some of 

 the affected animals have been of the most miserable kind, others have appeared to be in 

 the enjoyment of perfect health — facts which appear to me to favour the inference that 

 when actual mischief does take place, the cause may be due to the lesions induced 

 by the migrations of the growing and more or less mature parasite, rather than by the 

 microscopic brood in the blood. It would not surprise me, should it eventually be demon- 

 strated, that the haggard, loathsome appearance presented by the great number of the 

 pariah dogs of every Indian town is, in many instances, primarily due to the injuries in- 

 flicted on the vascular and other tissues of the animals by these parasites — a diseased 

 state which cannot be attributed to age or to want of food, for the associates of these 

 animals, under the same conditions, are perfectly healthy. 



In applying the lesson in pathology which these observations on animals appear to 

 afford towards the elucidation of the diseased condition associated with nematode 

 Hsematozoa in man, it should be specially borne in mind that the parents of these blood- 

 worms may be very much smaller than the mature Entozoa described above, conse- 

 quently their detection at a post-mortem examination may be even much more difficult 

 than is the case with the canine worms. 



That this is probably the fact, the experience of an accomplished pathologist. 

 Dr. McConnell, testifies, for, as already mentioned, he could detect no mature parasite in 

 the body of a person whose blood, during life, was known to be contaminated with young 

 Filarice. 



Since this paper was in type, I have, through the kindness of Dr. McConnell, 

 had the opportunity of examining all the organs of the body of another person whose 

 blood contained innumerable examples of these embryo- worms. The subject was a 

 Native, aged sixteen, who had been brought to the Medical College Hospital in a moribund 

 state. No previous history could be obtained, except that he had suffered from " fever," 

 and he did not appear to possess any friends in Calcutta. The youth died within a few 

 hours after admission, and Dr. McConnell made a post-mortem examination of the body 

 I on the following morning. No evidence of special disease could be found, but on making 

 a microscopic examination of a clot of blood from the heart he was surprised to fiind 



