HAKUVV'ICKE'S SCIENCE-GOSSIP. 



97 



EAPHIDES, SPHJIRAPHIDES, AND CRYSTAL PRISMS. 



By professor GULLIVER, F.U.S. 



ESPONDING to the 

 request of the editor 

 of Science-Gossip, 

 I proceed to give 

 some account oflthese 

 beautiful,'plant-crys- 

 tals. And this the more 

 readily because, so far as I 

 know, it would be idle to con- 

 sult our current floras and 

 other books, including those 

 specially devoted to micro- 

 scopic objects, for correct 

 definitions of these crystals, 

 and the use of them as charac- 

 ters in systematic botany ; 

 since in those works the subject 

 is either wholly neglected or 

 treated so perfunctorily as 

 still to require distinct reiteration. As space is 

 necessarily limited, the matter must now be confined 

 chiefly to such points as may invite and assist the 

 student. More ample details, especially as regards 

 my extensive and original observations on the value 

 of rapbides as characters in systematic botany, are 

 given in my papers, epitomized in the Popular 

 Science Review up to October, 1865, since continued 

 in the Annals of Natural History for November of 

 that year, and in many numbers of Seemann's 

 Journal of Botaiuj, and of the (Quarterly Journal of 

 Microscopical Science. 



On the present occasion, the matter concerning 

 the crystals maybe treated in the following order :— 

 1. Nomenclature ; 2. Taxonomy ; 3. How to find 

 the crystals ; 4. Their Microscopic Interest ; and, 5. 

 Their Composition and Use. And as we often meet 

 with private inquiries and public advertisements for 

 " good microscopic materials," so it will now be 

 shown that, even in this limited department, Nature 

 has scattered those very materials broadcast every- 

 where around us, whether in towns at Covent 

 No. 101. 



Garden, and druggists' shops, or in country fields, 

 ditches, and lanes. In the following woodcuts, 

 which are all copies of original drawings by mc 

 from nature, nothing is depicted that may not be 

 seen under an object-glass of half or quarter-inch 

 focus, and often of much less power. Of each 

 figure the objects are magnified somewhat to the 

 same degree, except when otherwise noted ; and 

 as their sizes are given in the text, specifications of 

 the enlargement are not necessary for perspicuity. 

 The student should examine some of the crystals for 

 himself, as he may easily do in the plants now 

 mentioned as always obtainable for this purpose. 

 In the text, for the sake of precision and the want 

 of English equivalents, some hard words are used ; 

 but all these are explained in most of our popular 

 floras or manuals. 



1. Nomenclature. — All microscopic plant-crystals 

 were formerly called rapbides, and this error, though 

 fatal to their taxonoraic value, is common now ; for 

 it is still perpetually confounding forms essentially 

 different, and occurring, if understood in this loose 

 and incorrect manner, almost indiscriminately or 

 generally in numberless plants that never produce 

 rapbides at all. 



Raphides, fig. 57. — These are the well-known 

 needle-shaped crystals occurring about a score in a 

 bundle, either plainly in a soft cell, as, e. g., in the 

 berry of Arum maculatum (fig. 57, c), or in intercellu- 

 lar spaces, without an evident special cell, as in old 

 fronds oiLemna trisulca (fig. 57,/), or devoid of any 

 distinct ceil or intercellular space, as in the ripe 

 berry of Tamus (fig. 57, e). However this may be, the 

 raphides, before they have been disturbed, always lie 

 loosely in contact, side by side, like needles in a 

 packet ; and so no wonder that they have been named 

 from a Greek word signifying a needle. The shaft of 

 each of the raphides is commonly smooth and 

 rounded, so that they move easily on and over each 

 other ; and it tapers gradually to a point at each end.. 

 Raphides have an average length of about y^^th of 



