Microscopical Essays, xSi 



being larger than in others. Repeated trials have (hewn me that 

 the whole progress may beeafily marked in the three following 

 kinds, with only a tincture of cochineal. 



Put half an ounce of cochineal, in powder, into half a pint of 

 fpirit of wine ; fei it in a warm place, and make it often for four 

 days; then filter off the clear tinclure. Put an inch depth of 

 this into a cup, and fet upright in it pieces of the rind of am, 

 white willow, and ozier, prepared as has been directed, by mace- 

 ration in water ; for in that way one trouble does for a hundred 

 kinds. Let an inch of the rinds alfo ftand up out of the tinclure. 

 After twenty-four hours take them out, clip off the part which 

 was immerfed in the fluid, and fave the reft for obfervation. 



To PREPARE THE BLEA. 



Cut the pieces in a fit feafon, either juft before the firft leaves 

 of Spring, or in the midfummer mooting time. Then we fee all 

 the wonders of the ftruclure ; the thoufands of mouths which 

 open throughout the courfe of thefe innumerable veffels, to pour 

 their fluid into the interftitial matter. 



Thefe veffels, which are in nature citterns of fap for the feed- 

 ing the growth of the whole tree, are fo large, that they are 

 capable of being filled with coloured wax, in the manner of the 

 veffels in anatomical injections ; and this way they afford pleafing 

 objects for the microfcope, and give excellent opportunities of 

 tracing their courfe and ftruclure. 



w 



A M ethos 



