Prof. Bailey on the Crystals found in Plants. 19 



croscope then showed these glimmering points to be beautiful 

 crystals, of the forms represented in figures 1, 3, 10, and 11, some 

 being single as in figure 1, and great numbers compound or twins 

 as in figure 2 b. 



When these crystals were heated they became opaque, and if 

 then placed in water or Canada balsam, they perfectly resembled 

 the polygonal bodies found in the ashes of wood, so that no doubt 

 was left as to the origin of the bodies in question. 



The general form of the crystals which I had thus detected in 

 the bark and wood of hickory, so much resembled the figures given 

 by Raspail* of crystals found by him in Iris florentina, that I had 

 but little doubt that they were identical, but a slight examination 

 showed that either Raspail had made an error, or the crystals of 

 the Iris and hickory must be different, as their forms appeared 

 incompatible, belonging to entirely different crystalline systems. 

 Raspail's figures represent modifications of right square prisms, 

 while the forms in hickory are evidently monoclinate,f being 

 derived from a right rhomboidal or oblique rhombic prism. Exam- 

 inations of the crystals in Iris florentina, and various other Irid- 

 aceous plants, such as Gladiolus psittacina, Crocus ver?ius, &.C., 

 convinced me of their identity in form with those found in hick- 

 ory, and that Raspail's representations of the terminal modifica- 

 tions are incorrect, and his measurement of the plane angles does 

 not agree exactly with mine. Those which he measured, he 

 states, gave 62^ and 149°, while both in the hickory and the Iris 

 the same angles as measured by me, gave 60° and 150°. He 

 ^appears also to have overlooked the fact, that the plane angles 

 * which are diagonally opposite on the same face are not equal, 

 being in this case 70° and 145°. (See figure 10.) 



Having mentioned to my friend Dr. Torrey the occurrence of 

 these crystals in hickory, he kindly furnished me specimens of 

 a South American bark, said to be used as a substitute for soap, 

 {Qinllaja saponaria?) which was filled with crystals precisely 

 similar to those found in hickory, and which I think he said he 

 had analyzed and found to be oxalate of lime. Raspail also 

 gives this as the composition of the crystals in Iris. The account 

 of the experiments which I made on these and other crystals, to 

 determine their composition, I shall give further on. 



* Nouveau Systeme de Chimie Organique, Plate viii, figs. 7, 8, and 10. 

 i Hemi-prismatic of Mohs. 



