OF DIGESTION. 147 



will not be so dissolved is every day proved by worms, maggots of flies \ 

 living in the stomachs of many animals ; and if it was a power that 

 could act upon a part that had the living principle, as well as an acid 

 can, then the stomach itself would certainly be dissolved. 



If one could conceive a man to put his hand into the stomach of a 

 lion and hold it there without hindering the digestive powers, the hand 

 would not in the least be digested ; and if the hand of a dead man was 

 put in at the same time, whether separated or not from the body, that 

 hand would be digested, while the other would not 2 . 



All carnivorous animals, as far as I know, both quadrupeds and 

 birds, throw up from their stomachs any substance that is not fit for 

 digestion which they swallow with their food : the eagle, hawk, owl, 

 &c, when they swallow hair or feathers and bone along with the meat, 

 afterwards throw it up ; because these substances not being dissolved 

 with the meat, they are left in the stomach, and by its action they are 

 coiled up into the form of a ball and then thrown up. The bones and 

 hair of a mouse coiled up, with dirt or sandy substance, is thrown up 

 from the stomach of an owl. 



It is the same with the dog ; for if a dog happens to swallow any of 

 these substances, they throw them up in the same manner. I have seen 

 a dog eat hay which was sticking to the meat, and afterwards throw it 

 up matted together. 



The blood which a leech sucks is not digested in the belly, but lies 

 pretty pure and but little coagulated ; and is absorbed into the substance 

 of the animal like the nourishment of a vegetable, and is there assimi- 

 lated, and the excrementitious parts are sweated through the skin. 

 Leeches are of that class which have no anus 3 . They are fond of 

 blood, but a very little kills them. If they have not sucked a great 

 deal they will live a long time with it in them, and spew it out a little 

 at a time ; but they seldom recover. The blood they suck is both venal 

 and arterial, because when we open them we find it is mixed, and of 



1 [The stomach bott, or larva of the (Estrus Equi, is the most familiar instance of 

 this kind.] 



2 [The Hydra viridis occasionally performs such an experiment for us, swallowing 

 one of its own arms along with its prey ; but, while this is dissolved, the living part 

 of itself is disgorged uninjured and resumes its functions. Nay, sometimes one 

 individual is swallowed entire along with a worm which a stronger polype may have 

 seized ; in this case the worm is digested, but the weaker polype soon disengages 

 itself from the stomach of its conqueror, apparently unaffected by the digestive 

 solvent. As Hunter's matured conclusions on the digestive process were published 

 by him (Animal Economy, pp. 81-121), his speculations in MS. on its 'fermentative 

 nature,' &c., are not here given ; having been, apparently, abandoned by him.] 



3 [The medicinal leech has a rectum and vent opening above the hinder sucker.] 



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