XII] REFERENCES 223 



When an infected Anopheles, containing filariae in its 

 proboscis, feeds on a dog, the worms escape through the fine 

 membrane (Button's membrane) uniting the labellae, and thus 

 get on to the surface of the skin. If this is sufficiently moist 

 they penetrate the epidermis, and may be found in the sub- 

 cutaneous tissues. The young filariae then make their way 

 towards the heart and great vessels of the dog, and there 

 develop into the adults. The worms may also be found in 

 other regions of the body, but in any case the embryos, on 

 being liberated, make their way into the circulation. Accord- 

 ing to Caleb and Pourquier the embryos may pass into the 

 foetal circulation, and therefore the disease may be transmitted 

 hereditarily. 



The pathogenic effects on the dog vary considerably ; weak- 

 ness, anaemia, cough, icterus, ascites and -lameness may be 

 observed and a fatal result is frequent. No effective treat- 

 ment is known. 



Filaria recondita Grassi, 1890. This filaria, which also inhabits the dogs 

 in many parts of the world, is closely related to F. immitis. Grassi and 

 Calandruccio have shewn that the embryos develop in the body of the dog- 

 flea (Pulex serraticeps), the cat-flea (Pulex irritans), and also in a tick (Rhipi- 

 cephalus siculus Koch). Although infection experiments with fleas gave no 

 positive results, it seems probable that these insects may serve as the inter- 

 mediate hosts for this filaria. 



REFERENCES. 



Calandruccio (1892). Descrizione degli embrioni e delle larve della 

 filaria recondita (Grassi). Atti dell' Accad. Giornia, vol. LXIX. 



Fiilleborn, F. (1908). Ueber Versuche an Hundefilarien und deren 

 Uebertragung durch Miicken. Arch. f. Schiffs. u. Tropenhyg. 

 vol. xii. Suppl. 8, 43 pp. 4 pis. 



(1912). Untersuchungen iiber die chemotaktische Wirkung der 



Malpighischen Gefasse von Stechmiicken auf Hundemikrofilarien. 

 Centralbl. f. Bakter. vol. LXV. pp. 349-352. 



(1912). Zur Morphologic der Dirofilaria immitis Leidy, 1856. 



Ibid. vol. LXV. pp. 341-349. 



Grassi and Noe (1900). Uebertragung der Blutfilariae ganz auf- 

 schliesslich durch den Stich von Stechmiicken. Centralbl. f. Bakt. 

 Orig. vol. xxvin. No. 19. 



