OOMMONER AILMENTS OF THE DOa IX (JHINA AND SOME SIMPLE REMEDIES 73 



in the Customs Gazette, October-March, 1876-77, is one which cannot be too carefully read. 

 He says : — 



"Anyone who has had much acquaintance with dogs in these parts must be aware of 

 their liability to sudden and apparently unaccountable death. Ten chances to one the 

 cause of death is found to be plugging of the pulmonary artery, or mechanical interference 

 with the action of the valves of the heart by a mass of filarice occupying the artery 

 and cavities of the right side. I say that one-half of all dogs in China, whether native or 

 foreign, are the hosts of this parasite. Anyone can satisfy himself on this point by examin- 

 ing with the microscope the blood of the first half-dozen dogs he can procure, and to do so 

 it is not necessary to kill the animal. Make a small incision with a sharp knife on the inner 

 surface of the ear, and from this express sufficient blood to supply six or eight slides. 



Of 40 animals whose blood was examined, the embryos of filaria hnmitis were found 

 in 15 ; and in post-mortem examinations ^/^n^ were found in the hearts of 8. According to 

 my measurements the immature hcematozoon is about jIts of an inch in length by ^Vinr 

 of an inch in breadth, and I have never seen any sign of growth or development in the 

 many specimens I have examined, the measurement and appearance of all being exactly 

 alike. 



There seems, then, to be no observed intermediate stage between an immature embryo 

 and a full gvovtn filaria. 



On opening the heart, the worms are found massed together in a bundle like a coil 

 of thick cat-gut. On unravelling and extending them, they can be separated into two 

 kinds; the larger plumper ones (females) measure from 8 to 13 inches in length by g\y of an 

 inch in diameter; the other smaller, 5 to 7 inches by Vu of an inch 



We have seen the two extremes of the parasite's life : the minute structureless 

 embryo and the mature elaborately organized parent a foot in length. But I have met 

 with no intermediate form: yet such there must be. Where to look for it I cannot 

 suggest — spleen, liver, kidneys, lungs, brain, all the viscera, in fact, in which I have 

 dissected them, have yielded no information. The degree of development effected 

 consists essentially in the elaboration of an alimentary canal, and a boring apparatus 

 wherewith to penetrate the tissues and assist the animal in its progress to its future 

 resting place. Now in the case of the filaria hnmitis, after a residence more or less 

 prolonged in some suitable medium, it is swallowed, or in some other way obtains access 

 to the tissues of the dog, then, by means of the boring apparatus with which it has become 

 provided, it penetrates, and working its way to some spot in or near a vein, it rests for a 

 time, loses all trace of its boring apparatus, and grows from probably a microscopic animal 

 to a length of many inches, and becomes provided with a complete set of reproductive 

 organs. This accomplished it finds its way along the vein to its final resting place, 

 the right side of the heart, where the important function reproduction of its species is . 

 performed. 



It is unlikely that a dog with many worms in the heart can be of much use in the 

 field ; his wind will go in the first half-hour of work. I would suggest, therefore, for the 

 protection of the sportsman who contemplates buying a dog in China, that he should have 

 its blood microscopically examined by a competent person; and if embryos of filaria 

 immitis are found in any quantity, that he should not make the purchase." 



