122 



In tlic sliidy III' till' seed characters of the genus Plantago, particular attention 

 was given to outline ;iiul to the structure of the seed-coat, and it was necessarv to 

 make cross-sections of the see<ls of each species. Preliminary to this the seeds of 

 each were phu'ed in water for a few lionrs, in order that they might be more easily 

 sectioned, wiicii the peculiar development of a Ijhie color in P. Virginica was 

 noticed. It was thought, at first, this might l)e due to some sut)stance contained 

 in the water used, so the experiineut was repeated, using distilled water with tlic 

 same unvarying results. 



An examination of literature showed that, in all probability, it wa> a 

 glucoside allied to Indican. This was further rendered probable because such 

 substances are found in widely separated families, as Euphorbia flncforia, and 

 Polygon iim tiiictoriu. 



The indigo plant is destitute of t'olor until treated with water. The broken 

 and bruised plants are placed in vats, covered with water and allowed to ferment, 

 and the indigo separates from the plants and is precipitated. Indican is s(duble 

 in boiling ether, boiling alcohol, glacial acetic acid, carbolic acid, petroleum, 

 chloroform and hydrochloric acid 



The seeds of P. Virginica, when dry, are golden yellow in color, and the cross 

 section showed the cell contents to be colorless. Within three hours after l)eing 

 placed in water they had turned black on the surface, but an examination of a 

 cross section showed the cell cimtents of the entire seed coat, except the outer row, 

 the cell contents of the cotyledons and even the cell walls to be a bright blue cohu-. 

 Since this color was developed in a similar way to that by which Indican is pro- 

 duced, the tests for Indican were tried, giving the following results: After the 

 color had been develoj)ed by water, thin sections were placed in 'J(i per cent, ali-o- 

 hol and boiled for ten minutes with no perceptible change. Sections were boiled 

 for three minutes in ether without any change in color. Others were kept in 

 glacial acetic acid for two hours with no change. Sections were kept in petroleinn 

 for twenty-four hours, and within that time thi' blue color was destroyed, leaving 

 the cell contents i-olorless. The blue remained unchanged after a two hours' treat- 

 ment with [)ure chloroform. Sections were ke[)t in carbolic acid for two hours 

 with no perceptible change. Hydrochloric acid destroyed the blue color within ten 

 minutes, and left the cell contents colorless. After comparing these results with 

 those of Indican, it was found that this blue substance in the seeds of Virginica 

 r&sembles Indican in that it is developed in the same way and gives the same re- 

 actions with nitric and hydrochloric acitls, sodic hydrate and petroleum. It dif- 

 fers from Indican, however, in being insoluble in boiliiiir ether, boiling alcohol, 

 glacial acetic acid, carlxilic .-icid and clilordfnnii. 



