264 Crystals in Testa and Pericarp of several Orders of Plants, 



for example, in Ogilvie's edition, published in 1859, of * Webster's 

 English Dictionary.' Perhaps some knowledge of the subject may 

 become popular, now that it has been illustrated by figures in 

 'Science Gossip' for May, 1873. But very httle seems to be 

 known about the short prismatic crystals ; for, in the last July 

 ' Quarterly Journal of Microscopical Science,' we find Professor 

 McNab, of Dublin, announcing the discovery, in Germany, of 

 " numerous crystals of calcium oxalate in the bracts of Medicago, 

 Trigonella, and Pocockia." 



The Short Prismatic Crystals in Leguminosm. — But these 

 crystals, so far from being confined to those plants, and still less to 

 their bracts, commonly occur abundantly in the calyces, leaves, 

 bracts, pods, and other parts of numerous species of the order. I 

 have found the crystals thus in Medicago, Melilotus, Trifolium, 

 Lathyrus, Pisum, Yicia, Onobrychis, Phaseolus, Mimosa, Chorozema, 

 Kobinia, and many other members of the same order. In these the 

 crystals were always present ; but not so in a few examinations 

 made of some species of a few more genera, including Ulex, Genista, 

 Lotus, and Acacia, in which the crystals were either very scanty or 

 wanting. In the leaves of Wistaria I found sphaeraphides with the 

 short prismatic crystals. Thus, so far as these researches have gone, 

 it appears that these last-named crystals are very beautiful, and 

 common, but not universal, in leguminous plants. 



Multitude of these Crystals. — In the course of these examina- 

 tions, a remarkable abundance of starch in the trefoils, and in the 

 other Leguminous plants which are most relished by ruminant and 

 other animals, was so apparent as to arrest the attention. But the 

 quantity of the short prismatic crystals was a much greater novelty 

 and surprise. In a bit, only yVth of an inch in length, of the mid- 

 rib of a leaflet of clover, I have counted ten chains, each containing 

 twenty-five of the crystals ; and thus, there being 250 of them in 

 view in that yVth of an inch of the midrib, an inch thereof would 

 contain no less than 17,500 of the crystals, without reckoning the 

 number in its branches and in the two other leaflets, or elsewhere. 

 And, by a like observation, no less than 21,000 of the crystals were 

 reckoned in one inch of the sutural margin of a single valve of one 

 pea-pod ; so that, multiplying this number by 12, the average 

 length of each of the four separate sutural margins of the full- 

 grown pod being three inches, we have in those sutures alone the 

 amazing number of 252,000 of the crystals ! 



Significance of these Crystals. — Professor Rollestone has some- 

 where made a remark to the efiect that structures which, from their 

 minuteness, or obscurity of function, appear insignificant or useless, 

 may in reality rise in connection with this fact into the more impor- 

 tance. Here we have crystals in cells, organized structures of great 

 beauty, regularity and constancy, and moreover most marvellously 



