4GG REPORT ON /OOLOGY, MDCCCXLIV. 



On the so-called Filarise in the blood, which should more 

 correctly be regarded as the young of some nematoid worm 

 arrested in their migrations, Gruby and Delafond have 

 instituted various researches. Gruby (Institut. 1843, p. 35 ; 

 or the Lancet, vol. ii, 1842, 1843, No. 8, p. 265; or 

 Annals Nat. Hist. vol. xi, 1843, p. 403), for instance, in the 

 month of February, observed, in the blood of a healthy, 

 strong Dog, ten or eleven years old, and which had been fed 

 upon horse-flesh, transparent worms ^th of a line in 

 length, which at the anterior, larger end of the body, were 

 provided with a mouth, and posteriorly presented a pointed 

 tail. They were very active, had a serpentine motion, and 

 were perceptible in the blood in every part of the Dog. 

 Gruby subsequently looked for these nematoid hseraatozoa 

 in 100 other dogs in vain. He afterwards continued his 

 researches with Delafond (Comptes rend us, Nr. 16, 1844, 

 p. 687), and among 250 dogs of every breed, of all ages, 

 and of both sexes, found five individuals whose blood was 

 charged with these young nematoda. The dogs were other- 

 wise perfectly healthy. Food, rest, exercise, and blood- 

 letting, had no influence on the number, form, and motions 

 of the young worms. The transfusion of two decilitres of 

 blood thus impregnated with nematoda, caused the blood 

 of a healthy dog to be verminous for only eight days, 

 whilst the blood of a healthy dog into which a litre of 

 verminous blood had been injected, was itself verminous for 

 seven months. Upon injecting frogs with the verminous 

 blood, the minute nematoda could be recognised in the 

 blood of these Batrachians during eight days, and did not 

 disappear until the blood-corpuscles of the dog also began 

 to disappear from the frog's blood. The blood was, on every 

 occasion, before it was used for injection, freed from fibriiie. 

 The minute nematoda were destroyed when the blood was 

 injected into serous cavities, or into the cellular tissue of 

 living dogs. Excepting in the blood of a dog, similar 

 ncmatode embryos were never met with elsewhere in one of 

 those animals, either in the excretions or secretions, the 



