554 Pathological Significance of Nematode Hcematozoa. [part hi. 



When, however, it is considered that tumours may be of parasitic origin, and 

 that they may be in very intimate relation with the vascular system, enclosed in 

 the same fibrous sheath, such as the tumours which may be frequently observed 

 along the aorta in dogs (Plate XXXVIII, Fig. 8), and which may well be conceived 

 as exercising pressure upon the thoracic duct and important nerves, the difficulty 

 of accounting for the erratic character of the disease is much simplified. Such 

 obstructing causes as these need not be permanent, and probably are but so, but, as 

 may readily be supposed, are very prone to recur in the same tissues, as such 

 parasites manifest remarkable tendency to attack a particular organ and even 

 particular parts of it. It is by no means improbable that the mature parasite 

 having deposited its ova or embryos may shift its position and remain quiescent for 

 a time in some out-of-the-way cellular tissue — sub-cutaneous or otherwise. 



It will be recollected that the entrance of the Filaria sanguinolenta into the 

 blood vessels of the dog was shown to be effected by the migration of young 

 immature worms (not exceeding yV^h of an inch in length) from the mucous surface 

 of the oesophagus by perforation of its walls, and subsequently by penetrating the 

 walls of the artery, thereby causing considerable disorganisation of the arterial tissue, 

 and leaving more or less extensive aneurismal sacs as indications of the spots where 

 the worm attained maturity. It is possible, and indeed highly probable, that a 

 somewhat similar course is taken by the mature parasite of which the Filaria 

 sanguinis hominis in the circulation is the offspring. It may be that it is not 

 the oesophagus that is pierced and the thoracic aorta specially attacked, for this 

 particular parasite may, perhaps, proceed as far as the duodenum, or still further 

 down the alimentary canal, before it commences to follow its migratory instinct, 

 and then find its way either directly into the aorta or reach the circulation by 

 some other channel, such as one of the mesenteric arteries. So that in this 

 instance the tumours and lesions may be along the walls of the abdominal aorta 

 or its renal and other branches, or even be situate in intimate relation to the 

 Receptaculum chyli and the principal lymphatics. It is equally evident that the 

 tissues along the urinary tract may be similarly attacked by the growing and 

 matured parasites — indeed these structures may be specially liable to be invaded by 



them. 



Moreover, since it has been demonstrated that parasites, such as the Filaria 

 sanguinis hominis can be detected in the capillary net-work of the blood-vessels, 

 we have become aware of a factor capable of exercising no inconsiderable force 

 compared with the resistance which the delicate walls of the capillaries of the 



Dr Sonsino he expresses his belief that the nematode which he found must be closely related to the 

 Filaria sanguinis hominis. A highly interesting account of his observation has been communicated to the 

 Academy of Naples. This fact relating to the htematuria of Egypt is particularly interesting, when it is 

 remembered that, some years ago, Dr. Wucherer discovered a microscopic nematode in the urine of a person 

 suffering from the haematuria of Brazil — although from the limited information we possess concerning these 

 two parasites it would be quite premature to refer them to the same species. 



