144 



THE EFFECTS OF PARASITES OX THEIR HOSTS. 



the periosteum, and thus riddles the skull. 1 Similarly, Pentas- 

 tomum tcenioides, parasitic in the nasal cavity of the dog, occasions 

 after some time (according to Chabert) distinct caries. In recently 

 infected animals an injection and loosening of the Schneiderian mem- 

 brane is all that can be observed. The effect of Pentastomum upon 

 the lungs is much more serious. I have already mentioned how, in a 

 snake (Naja haje) which I examined, it was evident even to the naked 

 eye that death had resulted from pneumonia caused by Pentastomum. 

 There were numerous inflamed regions in the lungs as large as the 

 palm of the hand, and bearing in their centre a Pentastomum firmly 

 fixed by its booklets. 



Even the horseleech (Hcemopis vorax), in tropical countries, and 

 especially in North Africa, is sometimes the cause of chronic in- 

 flammation in aggravated cases of laryngeal consumption, which 

 occurs when the animal is inadvertently swallowed by man or beast 

 when drinking, and settles in the throat or 

 larynx. Still more acute and serious are the 

 attacks made by the larvae of Musca (Lucilia) 

 hominivorax on the throat and nasal cavities 

 of their unfortunate host. Vercamer, a Belgian 

 army surgeon, reports of a soldier in Mexico 

 that in a short time these animals had, with 

 their oral hooks, eroded the glottis, and so 

 riddled and torn the pillars of the fauces and 

 the soft palate, that they looked " as if they 

 had been stamped by a punch." (van Bene- 

 den.) Even in our own country the physician 

 has often the opportunity of observing the 

 mischief wrought by insect larva?, especially 

 Musca vomitoria (Fig. 89) and Sarcophaga car- 

 naria, parasitic in cases of neglected wounds or 

 blennorrhoea. The abscesses caused in tropical 

 countries, and especially in America, by the 

 gad-fly and chigoe, are worth mentioning as 

 analogous phenomena. 



Perhaps we should also mention here the repeatedly observed case 

 of horses, in which the skin, covered with a herpetic eruption, was 

 literally inhabited by larval Nematodes. 2 Another problematical 



1 See Weijenberg, Archives nterlandaises sci. exact, et not., t. iii., p. 428, 1868. 



8 See cases cited by Rivolta, II medico veterinario Torino, p. 300, 1868 ; or Hering's 

 Repertor. f. ThicrkeUk., Jahrg. xxix., p. 373, and Sommer, Oesterr. Viertdjahrsschrift f. 

 Vcterinarkundc, Bd. xxxiv., p. 183. 



FIG. 89. Larva of Musca 

 vomitoria. (Nat. size and 

 enlarged. ) 



