204 THE UNIVERSITY SCIENCE BULLETIN. 



due to the glucoside being broken up and thus being rendered 

 harmless, instead of the barium being taken out of solution. 



Crawford also states that in dried plants found by him to be 

 inactive the barium has been converted into an insoluble form by 

 drying. Sections of dried plants give a sugar test more readily 

 than formalin or fresh material. This may be due to the glucoside 

 being broken up in the process of drying. Crawford found aqueous 

 extracts of the dried material ineffective, but experiments by 

 others with feeding the dried material show it to be as toxic as 

 fresh. This glucoside is soluble in water, as water in which sec- 

 tions have been soaked for some time show cuprous oxide crystals 

 on heating with Fehling's solution, and the extracted sections 

 have very few crystals in them. 



From the experimental data at hand my conclusions are : That 

 the toxicity of loco weeds may be due to some glucoside which is 

 present, but which may be broken apart by various reagents; that 

 the reactions which Crawford ascribed to barium are really due to 

 this glucoside, the presence or absence of which can be proved 

 more readily than the toxicity of such minute quantities of barium 

 as he says are present in the plant. 



ANATOMY. 



The Leaf. The leaf is compound, of few to thirty-seven or 

 more leaflets. These as well as the petiole are densely covered by 

 long unbranched hairs. (Figs. 1 and 2.) These occur equally on 

 both sides of the leaf, about fifty per square millimeter. Their 

 occurrence is shown in fig. 3. These hairs are composed of three 

 cells, the basal cell, above this a very short cell with dense proto- 

 plasmic contents, and a very long terminal cell with thick cellulose 

 walls. This terminal cell has no cutinized surface, as demon- 

 strated by chloroiodide of zinc, Sudan III, or safranin-hsema- 

 toxylin. There are small irregularities on the surface of this cell 

 of the hair. 



These terminal cells of the hair contain no living protoplasm. 

 Methylene blue penetrates the cell wall, but does not color any 

 contents. Haematoxylin stains the walls light violet, showing 

 they are cellulose, but stains no contents, the center seeming clear 

 and empty. Potassium iodide-iodine stains the contents of the 

 middle cell deeply, but shows no contents whatsoever in the long 

 terminal cell. Chloroiodide of zinc shows the middle cell stained 

 dark yellow (the wall being cutinized and the contents protein), 



