VOL. XXII.] PHILOSOPHICAL TRANSACTIONS. 557 



to feed on flesh duly prepared. On the other hand, I believe you think, as I 

 do, that raw flesh is not a natural food for us. I do not know that any nation 

 has, of choice, used to feed on raw flesh ; unless in cases of extremity, &c. 

 For I put a great difference between raw flesh, which is the common food of 

 carnivorous animals, and flesh duly prepared for our food. If there be any 

 such, I look upon it as an anomalous case ; like that of the lamb mentioned by 

 Gassendus ; and the horse that eats oysters, or the rat eating bacon, for want 

 of other food, and the swine sometimes eating poultry : Which latter I do not 

 take to be purely natural : but rather the effect of an appetite depraved by 

 custom ; because much of the hog wash we give to swine, arises from the coc- 

 tion of flesh for our own use; which inures them to the taste of flesh. 



I leave it to you to consider, from what reason, and for what use, the pas- 

 sage of flesh through the alimentary duct should usually he more quick, and 

 that of herbs more slow. And again, whereas nature seems to have originally 

 designed a large caecum in man, as in some other animals, how it comes to pass 

 that it is now of little or no use ; but shrinks up into an appendicula vermi- 

 formis : whether or not this may not partly proceed from our feeding so much 

 on flesh. 



Concernhig Excrescencies growing on IVUlow Leaves, &c.* By M. Anth. Fan 

 Leiavenhoeck, F. R. S. N° 26y, p. 786. 



I took some of the largest and greenest willow leaves, and having opened 

 the knotty part which is found in some of them, I frequently discovered 

 more than one sort of worms ; but none of them being full grown, I cut some 

 of those knots off the leaves, and opening one a little, I saw there was a worm 

 in it, and shut it together again. Having put several of these knots into a large 

 glass tube, that the worms might attain their full growth, I could not find that 

 any of them did so. I observed at the same time, that several of those knots 

 had no worms in them, but were almost full of the excrements of the worms 

 that had been there, and were dislodged through a small hole, which I could 

 perceive in the knots. 



Fig. 5, pi. 13, ABCD represents the leaf of a willow tree, in which are 

 •seven knobs or tumours, some of them with holes, as efg, another, as k, 

 shows the posture of the worm as it lay in that knob which I dissected. Se- 

 veral of the worms lay dead in the knobs, and considering what should be the 

 reason of it, I was at last aware that there was a small worm fast linked to the 



* The insects found in the excrescencies on willow leaves, belong to the Linuaean genera of Cynips 

 and Ichneumon, the larvse or caterpillars of the latter preying on those of the former, and frequently 

 preventing theirregular progress to the fly state. 



