NATURAL SCIENCES OF PHILADELPHIA. 



159 



crystal the cystolith so called because the aggregation of crys- 

 tals is inclosed in a capsule or cyst within a special cell, and is, 

 moreover, connected with its cell by means of a delicate filament, 

 differing in this particular from all other cell-contents. 



In our common nettle ( Urtica) we meet with tlie ordinary form 

 of cystolith. A simple aggregation of minute crystals probably 

 oxalate of lime nearl}- circular in form, showing the capsule 

 plainly which envelops them, and also the special cell containing 

 the cystolith. About six hundred fill a line an inch long, and 

 four hundred are found in one square inch. Each cystolith con- 

 tains about one hundred individual crystals. At lowest estimate, 

 therefore, forty thousand crystals exist in one square inch of 

 nettle leaf. 



In Pilea muscosa a near ally of Ur-tica I find a tj-pe of C3'sto- 

 litli differing widely from all forms heretofore described. They 



are elongated and bent, in form, like 

 an Australian boomerang. They 

 lie in cells measuring only the ^q 

 of an inch long, and the ^l^ wide; 

 and so abundant that quite one- 

 third of the entire leaf is occupied 

 with them. Cystoliths of this mag- 

 nitude and singular form I believe 

 to be unknown to botanists. The 

 filament connecting each one with 

 its cell-wall is apparent. 



What is the significance of these 

 plant-crystals? and there are 

 others more numerous and more 

 beautiful what their office in the 

 life of the plant? what part do they 

 act in supplying the salts of lime, 

 potash, and soda to the tissues of animals? AYill scientific agri - 

 culture answer ? 



lOOOth of an inch. 



The death of Thomas Sparks was announced. 



October 20. 

 The President, Dr. Ruschenberger, in the chair. 

 Twenty-four members present. 



Abies concolor in Colorado. Mr. Thomas Meehan announced 

 the discovery of Abies (Picea of Loudon) concolor in Glen Eyrie, 

 near Pike's Peak, in Colorado, by Dr. Engelmann. When, how- 

 ever, he explored what was till then an unknown caiion in 1871, 

 and which by right of a first discover}' he had named Caiion 



