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fishes,) the adipose substance of the common hog, and the 

 wax and honey of the bee, are extensively used for medical 

 and pharmaceutic purposes. And Prussic Acid, the most 

 powerful of all narcotic substances hitherto discovered, is 

 obtained from animal matter in a state of purification. 



Scarcely any article employed in medicine or surgery 

 is more extensively beneficial than the Spanish Fly (Can- 

 tharis vesicatoria), both from its external and internal 

 action on the living body. These beautiful, shining, 

 green-coloured insects, swarm in the forests on the south- 

 ern shores of Europe, feeding on the leaves of the ash and 

 the elder tree, and spread a strong and unpleasant odour 

 around them. Although some insectivorous Quadrupeds, 

 as the hedgehog, can eat large quantities of them with 

 impunity, their corrosive action on the human system is so 

 great, that they frequently inflame and excoriate the hands 

 of those who are incautious in collecting them ; and on this 

 corrosive property their chief medicinal virtue depends- 

 In cases of violent visceral inflammation, the external use 

 of Cantharides, as rubifacients or vesicatories, cannot be 

 supplied by any other medicine. They create a powerful 

 determination to the surface, and cause a copious effusion 

 of the serous part of the blood, by which the internal 

 action is relieved. They have so remarkable a determi- 

 nation to the urinary organs, that strangury is sometimes 

 occasioned by their external use ; and when administered 

 internally, they sometimes act so violently on the kidneys 

 and bladder, as to induce inflammation of these organs, 

 and a discharge of blood. From this tendency to excite 

 the urinary organs, they are employed in various diseases 

 connected with debility of the urinary and genital systems, 

 and likewise as a diuretic in dropsy. 



The Leech has been employed in blood-letting for more 

 than two thousand years ; its medical application is des- 

 cribed by Themison, who wrote before Celsus and Galen, 

 in the time of Augustus. Its use is likewise described 

 by Pliny } and is celebrated in the lines of Horace. This 



