100 



HARDWICKE'S SCIENCE-GOSSIP. 



parts, such as bulb-scales of the Shallot and fronds 

 of Lemna trisulca, may be examined very easily 

 ■without any such preparation. 



Fig. 61. p, Crystal Prism from ovary-coat of Centaurea nigra ; 

 q, different forms, one in its cell, from the same part of 

 Cmtaurea scubinsa ; r. Crystalline Cross, and three single 

 crystals, from bulb-scale of Shallot. All highly magnified. 



4. Microscopic Interest of the Crystals.— Oi all the 

 objects in the plant-tissues, there are none more 

 beautiful and more likely to interest the tyro in 

 micrographic botany than these crystals. While 

 under examination the glassy raphides roll about in 

 various directions, like a loose bundle of sewing- 

 needles thrown on a table. The sphaeraphides are 

 commonly contained in distinct cells, and the crystal 

 prisms are scattered and fixed in the direction of the 

 fibres of the plant, but sometimes, as in the Shallot, 

 lie across the tissue-cells. The prisms are well 

 adapted for experiments on the polarization of light, 

 as Colonel Horsley has often shown at the Canter- 

 bury meetings of the East Kent Natural History 

 Society. Any of the crystals may be easily pre- 

 served, either simply dried, or in balsam or dammar, 

 or in glycerine and other wet mediums. And when 

 numerous slides have been collected and correctly 

 labelled, their taxonomic interest will become 

 evident, and thenceforth go on increasing with the 

 increase of the collection, which may become an 

 important one for reference as to the value of the 

 crystals as characters in systematic botany. Thus 

 this might well be an elegant and useful occupation, 

 in which ladies could engage, for pleasing and instruc- 

 tive " half-hours with the microscope" ; and which 

 in this single subject would afford an extensive and 

 valuable cabinet of beautiful microscopic objects, 

 and rational researches that are not likely to be 

 exhausted after many half-years have been thus 

 employed. The inquiry might be extended to the 

 development of the raphides, from the ovule and 

 seed-leaves, to the different parts of the mature and 

 growing plants, to their decline, death, and rotten- 

 ness. For experiments of this kind the common 

 Onagracese of our gardens, fields, and lanes, and 

 the different species of OrnitJiogcdmn, would answer; 

 and they might be grown for the purpose in little 

 pots of various ' soils, and thus give perpetual 



pleasure and profit to any one with the mind and 

 means to use the microscope thus rationally. 



5. Nature and Use of the Crystals. — The crystals 

 are by no means, as maintained by eminent observers, 

 diseased or irregular products in plants, like calculi 

 in animals, but are so truly part and parcel of the 

 essential nature of the plant in which they occur, 

 that it cannot be well grown without producing 

 them, and this from the birth to the grave of the 

 species. Numberless examples of this truth may be 

 found in the plants of our common pools and fields ; 

 and I have often proved it experimentally in various 

 members of the dicotyledonous orders Balsaminacese, 

 Galiacese, and Onagracese, and in some Monoco- 

 tyledons. The crystals are mostly oxalate of lime, 

 with a small proportion of other earthy salts. 

 Though this, according to Professor Douglas 

 Maclagan, is the case with raphides, some of them 

 appear to be phosphate of lime, according to 

 examinations made, at my request, by the late John 

 Davy, of these crystals in TSpiloUum, Galium, and 

 Smilax {Ann. Nat. Hist., June, 1864). And tliis 

 leads us to a notice of the use of such crystals. 

 The Sarza of the Pharmacopoeia is a Smilax very 

 rich in raphides and starch ; and hence, probably, the 

 well-known efficacy of this drug in those diseases, 

 especially of the bones, in which there is a deficiency 

 of the earthy phosphate. In like manner the Duck- 

 weeds abound in raphides and starch, and on these 

 plants young mammalia, water-birds, and lower 

 animals feed greedily; and no doubt this is the 

 very pabulum best adapted for the nourishment 

 and growth of the bones and other parts. Many 

 animals are ever feeding on seeds in which 

 microscopic crystals abound. Thus we come to 

 understand some of the manifold ways in which 

 Nature has provided for the wants of her creatures. 

 We have seen that science too can turn these 

 crystals to good taxonomic purpose ; and it may be 

 added that they are often the best tests of the 

 genuineness of many vegetable drugs ; such as Orris, 

 Quillaja, Guaiacum, and Rhubarb. The false or 

 American Sarza, being an Aralia, is at once plainly 

 distinguishable by its sphseraphides from the 

 genuine Sarza. Again, as manure, the calcareous 

 salts which compose the crj'stals must be of great 

 value ; nature storing a superabundance of them in 

 the living plant, to be restored in the dead leaves 

 and other parts to fertilize the earth. Accordingly, 

 we see good reason why the gardener so carefully 

 husbands his leaf-mould; and that such plants 

 as the Duckweeds, Puchsias, and Willowherbs, 

 should, from their profusion of raphides, in this 

 respect best serve his purpose. In fine, as poor 

 Charlotte Smith, who loved our wild flowers so well 

 and truly, sung of them : — 



" AU are for use. for health, for pleasure given, 

 All spealt in various ways the bounteous hand of heaven." 



Canterbury, March 6, 1S73. 



