3-18 PHILOSOPHICAL TRANSACTIONS. [aNNO IOQQ. 



On the Generation of Fleas. By Sig. D. Ceslone. N° 249, P- 42. 



Fleas bring forth eggs, or a sort of nits, from which are hatched worms ; 

 these make bags like silk-worms, and from these bags come fleas. They de- 

 posit their eggs on dogs, cats, men, and other animals infested with them, or in 

 places where they sleep, which being round and smooth, slip commonly down 

 to the ground, or fix themselves in the folds or other inequalities of the cover- 

 lets and clothes. From these are brought forth white worms, of a shining 

 pearl colour, which feed on the branlike substance which sticks in the combs 

 when puppies are combed to take out the fleas ; or on a certain downy substance 

 that is found in the folds of linen-drawers, or other similar things. In a fort- 

 night's time they come to the size of fig. 1, pi. 7 , and are very lively and active ; 

 if they have any fear, or be touched, they suddenly roll themselves up, and 

 make as it were a ball. A little after they creep as silk-worms do that have no 

 legs, with a brisk and swift motion. When they are come to their usual size, 

 they hide themselves as much as they can, and bringing out of their mouths the 

 silk, they make round themselves a small bag, white within as paper, but with- 

 out always dirty and fouled with dust. The bags are to the natural eye of the 

 size of fig. 2, without magnifying. In two weeks more in the summer-time, 

 the flea is perfectly formed ; then it soon leaves its exuvias in its bag, as silk 

 worms and all caterpillars do ; which leave in the same their exuviae. The flea 

 so long as it is enclosed in the bag, is milk-white, and has legs, but two days 

 before it comes out, it becomes coloured, grows hard, and gets strength, so 

 that coming speedily out, it straight leaps away. 



Fig. 3, represents the eggs ; fig. 4 the worm ; fig. 5 the bag ; and fig. 6 the 

 flea ; but all magnified by the microscope. 



To make Tivo clear Spirituous Inflammable Liquors, which being mixed together, 

 give aflne Carnation Colour, without either sensible Fermentation or Alteration. 

 By Mons. Geojfroy, F. R. S. N° 24g, p. 43. 



To make the first of these liquors, put a small handful of dried red roses into 

 a glass bottle ; pour on them rectified spirit of wine till it cover them an inch. 

 ' Let them infuse in the cold altogether in the bottle for 4 or 5 hours ; then pour 

 off the spirit of wine, which will be clear and colourless. 



The second liquor is made by putting some drops of good spirit of vitriol, or 

 oil of sulphur, into some good spirit of wine, so that the acid taste can scarcely 

 be discovered by the tongue. If you put a little of this last liquor into the first. 



