PART III.] Mature Parasites Associated with Embryos in Dogs Blood. 615 



of parasitism affects at least an equal proportion of dogs in China.* The embryos 

 which have been found in the dog's circulation appear to correspond as to size, form, 

 and character of movements, irrespective of the countries in which they have been 

 found ; and, were it not that discrepancies exist as to the relative prevalence of the 

 mature forms of the nematoid parasites which have been found in different countries, 

 an easy decision might be arrived at as to the parental form in all. As this is a subject 

 having considerable bearing on the elucidation of the genetic relations of the embryos 

 of an allied condition in man, it is necessary that the matter should be closely 

 scrutinised. 



Two, or possibly three, mature parasites have been observed as being more or less 

 frequently associated with the presence of embryos in the blood of dogs : they have 

 been found in the heart, in the arterial walls, etc., and in the subcutaneous tissues. 



The earliest record of such mature parasites associated with the existence of 

 embryos is found in the account of MM. Grruby and Delafond's experiments, where 

 it is stated that on one occasion (out of a total of 480 dogs the blood of 20-24 of 

 which had contained embryos) they found six white, filiform worms, in the right 

 ventricle. They were from five to eight inches in length (14 to 20-24 ^centimeters) 

 and from -^^ to yV iii^h in width. Two of the specimens were male and four female, 

 the latter being full of ova and embryos ; the embryos identical in appearance with 

 those found in the blood.t This observation, as regards Europe, appears to have 

 remained unique for many years, but latterly MM. Galeb and Pourquier say that 

 they have found the heart of a bitch stuffed with such adult filarise, the female specimens 

 being 30 to 32 centimeters in length ; and, the animal being pregnant, they further 

 discovered that the blood of a foetus, which was examined, contained many " embryons 

 hematiques." The male examples of the parasite were thinner than the female, and 

 only half the length. 



These mature worms are considered to be identical with Leidy's Filaria mimitis^X 

 for a very careful description of the minute anatomy of which we are indebted to 

 Brigade Surgeon Welch, F.E.C.S. § ; as also to Dr. Cobbold || and Dr. Manson.^ They 

 appear to be extraordinarily common in China. Manson found them, for the most 

 part, coiled up in the right ventricle, sometimes extending through the tricuspid valve 

 into the auricle, and even into the superior vena cava, and very generally through 

 the semilunar valves, far into the pulmonary artery and its branches. He never found 

 them in any other vessel, though carefully sought for. The female specimens measured 

 from 8" to 13" in length by jV' i^ width ; and the male, recognised by its corkscrew- 

 like tail, from 5" to 7" in length and ^V in width. 



* '• Report on HaBmatozoa" in China Customs Medical Reports, vol. xiii. Shanghai, 1877. 



f Comptes Reohdus, t. xxxiv, pp. 11 — 13, 1852. 



% Proceedings of the Academy of Natural Science, Philadelphia, vol. v, 1850-51. 



§ Monthly Microscopical Jowrnal, October 1873, p. 157. 



II Proceedings of the Zoological Society, November 1873. 



4 Op. cit., pp. 1—11. 



