64 THE CANADIAN NATURALIST. [Vol. ix. 



the insects by aid of the microscope, the subsequent development 

 of the Filarla could be well made out : it passes through three 

 stages, in the last of which " it becomes endowed with marvellous 

 power and activity. It rushes about the field (of the microscope), 

 forcing obstacles aside, moving indifi'erently at either end, and 

 appears quite at home."' Referring to the papillae which, ap- 

 pearing at one extremity of the creature, are supposed to be the 

 boring apparatus, Mr. Manson says : *' This formidable-looking 

 animal is undoubtedly the Filarla sanguinis homijiis, equipped 

 for independent life, and ready to quit its nurse the mosquito." 

 And concerning the subsequent history of the creature he remarks 

 that the Filaria, " escaping into the water in which the mos- 

 quito died is, through the medium of this fluid, brought into 

 contact with the tissues of man, and that, either piercing the 

 integuments, or, what is more probable, being swallowed, it 

 works its way, through the alimentary canal, to its final resting 

 place. Arrived there, its development is perfected, fecundation 

 is afiected, and finally the embryo Filarice we meet with in the 

 blood are discharged in successive swarms and in countless num- 

 bers. In this way the genetic cycle is completed." 



It is in warm climates that the presence of these microscopic 

 worms is most to be feared. In Brazil, Demerara, India, China 

 and other tropical countries, the existence of Filaria has been 

 but too clearly made out, and that its presence is associated with 

 painful and disgusting diseases, and " not improbably with leprosy 

 itself." It is found too in Natal, in company with a noxious 

 parasite of another kind. If, as is thought, there is some rela- 

 tion between the infested blood atid certain epidemics, the 

 question is one well deserving of careful study. — Chambers' s 

 Journal. 



Published March 22, 1879. 



