THE 



MONTHLY MICROSCOPICAL JOURNAL, 



OCTOBER 1, 1873. 



I. — A Description of the Thread - ivorm, Filaria immitis, 

 occasionally infesting the Vascular System of the Dog, and 

 remarks on the same relative to Hmmatozoa in general, and 

 the Filaria in the Human Blood. By Francis H. Welch, 

 F.R.C.S.E,, Assistant Professor of Pathology, Army Medical 

 School, Netley, Southampton. 



Plates XXX., XXXI., and XXXII. 



Since the discovery of microscopic filariae in the human blood in 

 India by Dr. T. Lewis, Army jMedical Department, fuUy detailed 

 in the Annual Eeport of the Sanitary Commissioners of the Go- 

 vernment of India, 1871, Appendix E, a much greater interest has 

 naturally been thrown upon the presence of similar or congener 

 forms in the blood of animals, and hence any collateral evidence 

 which natural history can furnish tending to the elucidation of the 



EXPLANATION OF THE PLATES. 

 Plate XXX. 



Fig. 1 X 25 diameters. — The anterior end of female worm ; the musculo- 

 cutaneous tube split up to within a short distance of mouth and folded back ; the 

 alimentary and generative tubes turned out. 



(a) mouth, (6) oesophagus, (c) alimentary canal with contents, ((I) vagina, 

 (e) water vascular canals. 



Fig. 2 X 25 diameters. — Tail end of female, showing (a) csecal termination of 

 the alimentary tube, (6) looped commencement of the ovarian tubes, (c) cupped- 

 shapen cuticular orifices of the water vascular canals. 



Fig. 3. — Female worm, natural size, curled up for convenience of sketching. 

 Head, the left end. Tail, the right end in Plate. 



Plate XXXI. 



Fig. 4 X 75 diameters. — Vagina, showing the longitudinal and circular 

 muscular layers, and the canal, containing free embryos, becoming bulbous before 

 opening on the exterior of the body. 



Fig. 5 X 75 diameters. — Uterine canal taken from about the centre of the 

 worm, and containing ova and embryos. The wall is extremely delicate, with 

 longitudinal striae and so-called calcareous corpuscles. 



Fig 6 X 75 diameters. — Alimentary canal taken from about the centre of the 

 worm. The wall is delicate, with longitudinal and circular striae. The contents : 

 fat-granules, and apparently blood colouring matter. 



Fig. 7 X 75 diameters.— Uterine canal, taken 4 inches from the tail end of the 

 female worm, showing its connection with one of the ovarian tubes, and the 

 presence in both of germ cells, more highly magnified in Fig. 8. 



VOL. X. O 



