ECHINOCOCCUS HOMINIS. 231 



mals. Hydatids have been found in all the textures and cavities 

 of the human body, except the intestinal canal." They are very 

 common in sheep, oxen, and in pigs, when the pork is vulgarly 

 denominated measley. 



Ectozoa. — With respect to the Ectozoa, it may be remarked, 

 that they are usually the larvce of various species of insects, which 

 find their way into the body, and are often discharged in a living 

 state. It is well known that the larvae of the Tenebrio Molitor, 

 and T. Obscurus, or meal-beetle, (Pl. XXIX. A. fig. 5.) has often 

 been voided, either by the mouth, or per anum, and in one instance 

 is said to have occasioned death.* Dr. Martin Lister mentions 

 an instance of a girl who vomited up three hexapod larva?, similar 

 to what are found in the carcases of dead birds, which is supposed 

 to have been either the genus Dermestes or Anthrenusf. The 

 larvae of some insect, probably belonging to the genus QLstrus, or 

 gad-fly, have been discharged from the maxillary and frontal 

 sinuses. In South America, according to Humboldt, a species of 

 gad-fly, the (Estrus ho?ninis, of Gmelin, deposits its eggs in the 

 skins of man, causing there painful tumours ; and in this country 

 the gad-fly of the ox ((Estrus bovis) has been known to oviposit in 

 the jaw of a woman, and the bots (Pl. XXIX. A. fig. 6.) produced 

 from the eggs finally caused her death]:. The larvae of the com- 

 mon cabbage butterfly (Pontia brassicce) has frequently been dis- 

 charged from the stomach and bowels ; and Linneus tells us that 

 the caterpillar of a moth (Aglossa pinguinalis), common in houses, 

 has been likewise found in a similar situation. The larvae of 

 Helophilus pendulus, (Pl. XXIX. A. fig. 7), a fly peculiarly 

 formed by nature for inhabiting fluids, has been found in the 

 human stomach. § 



* Tulpius, Obs. Med. 1. ii. c. 51, t. 7, f. 3. Edin. Med. and Surg. Jour. No. 35, 

 42, and 48. Derham, Physic. Theol. 378. Lowthrop, in Phil. Trans, iii. 135. 

 Pickells, Trans, of the Coll. of Phys. in Ireland, iv. art. vii.11'24. 



t Phil. Trans. 1665, x. 391. 



J Clarke, in Lin. Trans, iii. 323, note. 



^ Phil. Mag. ix. 366. 



