28 



characters presented by raphldes. For exatople, in the British 

 flora, the sharpest and shortest diagnosis of the order Onagracese 

 would be Calycifloral Exogens abounding in raphides ; and so in 

 like manner of the order GaliaccjE and Ealsaminaceas. But as 

 already intimated, these valuable characters are always ignored, 

 and would not avail if we still persist in the error of confounding 

 very different crystals under one name. To conform to the truth 

 in nature, microscopic plant-crystals may be distinguished thus : 

 I. Ka]:hiiles, oecurring loosely in bundles, commonly within a cell, 

 eacli crystal with a rounded shaft vanishing both ends to points 

 and so like a needle as to derive their name from the Greek word 

 for that useful implement. 2. Long Crystal Prisms, which are 

 also needle-like forms, but with faces and angles to the shafts and 

 tips, and occurring either singly, or two or three so consolidated 

 together that they never admit of motion on each other. 3. Short 

 Prismatic ("rystals, cuboid, lozenge-shaped, square, and other forms 

 more or less prismatic, immovable, and contained in cells firmly 

 impacti'd in the tissues, mostly in chains along the vascular bundles 

 of the plant. 4. Sphoeraphides, more or less globular or lenticular 

 forms, commonly dispersed throughout the leaves and some other 

 parts of plants. Sphseraphidcs are offer granular, smoothish, or 

 stellate on their surface. Any two or more of the foregoing varieties 

 of crystals may occur together in the same plant 



Mr. Hammond's beautiful preparations were confined to the 

 Butelier's Broom, in which tlie raphides are not so large and distinct 

 as in some other orders. But excellent specimens of all the crystals 

 may be found at any season. Raphides in any common Onagrad, 

 such as the Fuschias and Willowherbs, in the Orchids, Star of 

 Bethlehem, official Squill, &c. ; Long Crystal Prisms, in the leaves 

 of the Iris, and in the so-called Sweet Orris, in the wood or bark of 

 Quillaja and Guaiacum ; Short Prismatic Crystals in the leaves and 

 other parts of many order of plants, well seen in most Legumens, 

 such as the Dutch Clover, &c.; Sphaeraphides in the Nettles, 

 Pelletory of the Wall, Spindle Trees, Ehubarb, &c. One or other 

 form of such crystals often affords an excellent test, as Mr. Harvey 

 would ]irovc, of the genuineness of a drug. In "Science Gossip," 

 May 1st, 1873, engravings were given of all the crystals, except 

 the short prismatic forms, which are shown in a plate of the 

 '• Monthly Microscopical Journal," December, 1873. 



The Society were very ihanklul to Mr. Hammond for his instruc- 

 tive slides, and expressed a wish that he would make more contri- 

 butions of the same kind, as they may illustrate a branch of photo- 

 tony hitherto too much neglected It was mentioned that Mr. 

 Hammond's skill might be profitably extended to slides of the 

 raphides in the leaves of Hydrangia, the sphoeraphides in the leaves 

 of Euonymus and the Wall Pelletory, and the short prismatic 



