THE PLANT WORLD 271 



most commonly found mixed with the seeds of grass and clover offered 

 for sale. Accompanying these are live plants of each kind of weed so 

 introduced. 



Impurities. — In open bowls and under magnifiers are shown samples 

 of different grades of the more common grass and clover seeds. These 

 are so arranged that seeds of the same kind but of different qualities may 

 be easily compared. In tubes in frames on a nearby screen are exhibited 

 the results of purity and germination tests of the same seed samples shown 

 under the magnifiers. Here can be seen in connection with each sample 

 the actual quantity present of dirt, chaff, weed seeds, and adulterants, 

 as compared with the quantity of seed that will grow. The price at 

 which these seeds were sold to the public is stated in each case, as well 

 as the actual cost of the pure seed that will germinate and grow. 



Cheap adulterants. — Several of the samples illustrate the use of the 

 seed of Canada bluegrass, meadow fescue, and yellow trefoil as cheap 

 adulterants. In most cases the adulterants so closely resemble the seeds 

 with which they are mixed, that they can not be distinguished except by 

 careful examination with the aid of a magnifying glass. 



DRUG AND MEDICINAL PI.ANT INVESTIGATIONS. 



The exhibit of Drug and Medicinal Plant Investigations consists of 

 crude drugs, shown in some cases in bags in large quantities and in other 

 cases in small .samples in glass jars. 



Native crude drugs. — Twelve specimens exhibited in quantity repre- 

 sent drugs either at present grown in this country or considered well 

 adapted for growth in the United States or its dependencies. A growing 

 plant in a tub accompanies each of these bags and shows the living plant 

 concerned. In the cases of cinchona, eucalyptus, and cascara sagrada, 

 where mature trees furnish the products exhibited, young trees are shown 

 in the tubs. 



Native commercial drugs. — In a case at the end of the exhibit are 

 shown about a hundred kinds of commercial drugs, all of which have 

 been produced in the United States and nearly all from wild plants, though 

 in a few instances samples from cultivated as well as from wild stock are 

 shown . 



POISONOUS PLANT INVESTIGATIONS. 



The poisonous plant exhibit consists of two parts : 



Plants poisonous to man and to live stock. — First, water-color illus- 

 trations of over fifty plants poisonous to mankind and to stock, in two 

 groups, one representing those chiefly poisonous to man, and the other 

 those poisonous to stock. In some cases, especially in the former class, 

 plants which are sought and for which poisonous plants are sometimes 

 mistaken are also exhibited, the grouping bringing together, for com- 

 pari.son, the species confused. Nearly all the water colors are the work 

 of the late Mr. Walpole, of the Department of Agriculture, who 

 painted the various subjects from the living plants. 



Methods used in counteracting the effects of poisons. — The second part 

 of the exhibit is shown in a case, on one side of which will be found 

 apparatus made use of in connection with poisonous plant investigations, 



