l60 PHILOSOPHICAL TRANSACTIONS. [annO 1704. 



I took a little of the said sap, and put it upon my thumb-nail, letting it dry 

 there, and observed that it left a yellowish colour behind it ; that the particles 

 of salt had coagulated on my nail after the same manner as a foggy moisture is 

 congealed in winter on glass-windows; and the next day I perceived a reddish 

 colour where the sap had lain ; and where it had been thickest, the red was 

 deeper, which we call a peach colour. I tried the same experiment upon two 

 other nails of my hand, and the success was the same, and the colour lasted 

 several days. 



I cut a small splinter of the wood, in which there had been some of the aloes* 

 sap, but in which at that time there was but little colour to be seen; and placing 

 it before a microscope, I saw that it gradually assumed a peach colour, which in 

 some places was as bright and as fine as I ever saw. Cutting off a slice of the 

 aloes-leaf from the thickest part of it, which appeared as abc, fig. ll, which 

 letters represent the side of the leaf, that, as I imagined, was next the plant; 

 like as cda the other side, which one would take to be the back of the said 

 leaf. That part of the leaf which may be considered its skin or rind, and in 

 which the parts represented in fig. 4, 5, 6, and 7j are for the most part shut up, 

 is the space which is represented in fig. 11, between bp, or dh; and between 

 EFGH lies the forementioned slimy or viscous substance; in which I could not 

 discover any vessels that run through the middle of it, like those which pro- 

 ceeded out of the large canals, and spread themselves to the innermost parts of 

 the leaf, and were exceedingly small and numerous. 



I placed another slice of the aloes-leaf (which was also about the thickness of 

 the back of a knife) upon a clean glass, and viewed it several times, for the sake 

 of the fine peach colours that were to be seen in it; and I observed in it a kind 

 of oval figure, thai lay in exact order, with its sap shut up in it, after it had 

 been dry about 3 weeks. Fig. 12, defgh shows the said oval membrane; and 

 FIG that part which I call the canal, and by which I suppose it receives its in- 

 crease and inward matter. In this figure are seen a great many fibres, which I 

 concluded it had borrowed from other membranes, as well from those that lay 

 upon it, as from those that lay under it. Now if we consider that these mem- 

 branes cannot be coagulated by the air, since they are not formed by every eva- 

 poration or exhalation of the moisture; but that such membranes must doubt- 

 less be composed of an infinite number of fibres, so small as to escape our sight, 

 we have fresh cause to be surprised, at the inconceivable wonders shut up in 

 such a leaf. 



Fig. 10, rpabcsqr shows a small part of the rind or bark of the leaf, as it 

 was cut off across between d and h, in fig. 11, and dried up irregularly; which 



