552 T RANS. ST. LOUIS ACAD. SCIENCE. 



the breaking up of the cell-wall. Hanstein's aniline^ ^ mixture 

 colors characteristic mucilage red with a tinge of purple. Cora- 

 line gives to the mucilage derived from starch a red color which 

 is not removed by boiling in alcohol. Gums do not color by 

 rosolic acid. ^2 



Microchemical tests have been made by Nageli"*^ and Hofmeis- 

 ter^^ on the spirals of Salvia Hormiutn. The swollen portion 

 of the fruit of Salvia is colored blue on the addition of iodine 

 water and iodine alcohol. When the iodine and sulphuric acid 

 are of certain concentration it always becomes blue. In Salvia 

 Hortnium this substance was blued by the presence of iodine, but 

 it becomes reddish on the addition of sulphuric acid. The thread 

 remains uncolored. Teesdalia nudicaulis behaves in the same 

 way. Iodine and sulphuric acid color the mucilaginous cell-walls 

 oi Linum usitatissiimim blue. 



Frank,* ^ who has given us an exhaustive study of the micro- 

 chemical reactions for a large number of mucilaginous seeds, 

 pericarps, and tissues, concludes that this substance is either 

 cellulose or gum. It is gum (in part, the gum and mucilage of Beh- 

 rens) in the epidermal cells of the seeds of Z^z«?^;;z and Plaiitago. 

 It is derived from the secondary membrane of the cell-wall. In 

 the tissues of JMalvacece it is also derived from the cell-wall. The 

 mucilage found in the parenchyma cells of Symphytum is a gum, 

 and is derived from cellulose. The gum of Cycadacece, Alarat- 

 tiace<£ and Tilia is derived from the substance in the intercel- 

 lular passages. The mucilage in the cells in tuberous-rooted 

 orchids is derived from the starch of the cell-contents. 



In Salvia sylvestris iodine causes no change, but iodine and 

 sulphuric acid color not only the mucilaginous cell-sheath, but 

 the spiral band, a deep blue. The mucilage of quince-seeds, 

 Ocimiim basiliciitn^ Riiellia., and others, is related to it. 



Hofmeister*^ says that the mucilaginous substances in the 

 seeds of Collomia^ AcantJiodiiun ^ Rticllia^ Teesdalia, Pyrus 



41. Hanstein, Ueber d. Organe derHarz-und Schleim-Absonderung in den Laubknos- 

 pen. Bot. Zeit. 186S. p. 700, &c. 



4«. Behrens, 1. c, p. 33S, 367; Goodale, Physiological Botany, p. S'»99> Fluckinger 

 & Tschirch, Pharmacognosy, Engl, translation, p. 169; Frank. Jour, fiir Pract. Chem., 

 vol. xcv. p. 479, &c. &c. 



43. L. c, p. 119. 44. L. c., p. 30. 



45. L. c, p. 197, 19S. 46. L. c.,p. 29. 



