544 Pathological Significance of Nematode Hcematozoa. [part hi. 



aorta and swinging itself across the lumen of the artery (Plate XXXVIII, Fig. 7). 

 I have observed the channel of the aorta almost entirely blocked up after death by 

 a clot which had formed around a worm in this position. 



When the parasites have acquired a length of about fths of aii inch to an 

 inch, and a transverse diameter of about jVth, they will be found to have acquired 

 nearly all, if not all, the microscopical characters distinctive of the Filaria 

 sanguinolenta ; and, as already mentioned, every stage in the development may be 

 represented by examples of the parasite in the tissues of a single aorta — in the 

 thoracic portion of it : I have never observed the abdominal aorta to be affected in 

 this manner, nor have I observed the parasite in this condition in any tissue beyond 

 the limit of the thoracic cavity. 



(3) — -With regard to the third heading into which the pathological features of 

 this phase of parasitism has been divided, namely, the sacculated external and 

 scarred internal appearance of the aorta, it may be observed that these changes 

 appear to have been produced by the development of the Filaria as above described, 

 by their subsequent migration to adjoining tumours and various tissues ; and probably, 

 also, by the death and subsequent softening and absorption of some of the parasites 

 — an assumption supported by the fact that, frequently, on pricking an affected spot 

 of this kind, on the walls of the aorta nothing is found except an accumulation of 

 soft pultaceous substance filled with fatty molecules and plates of cholesterin. 



(4) — Sometimes the three foregoing classes of morbid appearances may be found 

 to occur in a single animal ; indeed, the only occasion on which I observed the 

 condition described under the fourth heading, now to be referred to, was also associated 

 to some extent with the other three. The blood of a dog was found to be affected 

 to a slight degree with Hsematozoa, and the aorta was scarred and nodulated ; but no 

 mature parasites could be detected anywhere, except in a tumour in the walls of the 

 oesophagus. On careful examination of the thoracic viscera, however, a gland, or what 

 seemed to be one, was observed to have become enlarged and softened near the origin 

 of the left carotid artery. (Plate XXX VIII, Fig. 8.) This tissue, on being cut into, 

 was found to have degenerated into a pultaceous mass composed of oil molecules and 

 plates of cholesterin ; but coiled in the midst of this softened material were five 

 mature specimens of the Filaria sanguinolenta — male and female. 

 / This observation shows that the mature parasites, at all events, may be found in 

 other tissues than those of the thoracic aorta and oesophagus. 



It is not deemed necessary to enter into any very minute description of the 

 anatomical characters of the mature Filaria sanguinolenta as found in dogs in 

 India, as these do not differ very materially from those of various other Filarise which 

 have been described by various writers from time to time. 



The figures in Plate XL will, I trust, be sufficient to give a tolerably clear idea 

 of the general appearance and internal anatomy of the mature Entozoon when examined 

 under the microscope ; but it should be remarked that, in some instances, a higher 



