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stituents in plants and a fact which is not mentioned, is in 
annually selecting for seed purposes, plants yielding the highest 
percentage of active constituents. 
The thirteenth chapter deals with the algae in fresh-water 
supplies, specially with the working of the lakes and water bloom 
caused by various species of algae, chief among which are Beggia- 
toa, Anabena, Lymbya and Clathrocystis. The first remedy sug- 
gested for preventing these growths in reservoirs is to cover the 
reservoir. This, of course, is impracticable and would result in 
more harm than good if it were possible of application. The use 
of copper sulphate as an algicide is then considered. 
Chapter XIV catalogues the more important poisonous plants 
of the United States and Canada. The material in this chapter 
is elaborated on and forms the basis of the second part. This 
part, consisting of 827 pages, includes all groups of plants from 
the bacteria to the flowering plants. In the beginning there is a 
key to the plant kingdom which is purely descriptive. This 
description is elaborated under each order. The plants con- 
sidered poisonous are placed after the family; their description 
and habitat is given, and detailed descriptions of symptoms of 
poisoned animals and treatment as in Part I are frequently 
included. 
This part is very broad in scope and names plants which are in 
daily use as staple articles of food, as rye, oats, wheat, and corn. 
These are mentioned as poisonous for the reason that when they 
are attacked by fungi they are injurious. The attack of the 
fungi completely changes the nature of their constituents and 
their structure, as is well illustrated by ergot. Ergot is no longer 
rye, but the resting stage of Claviceps purpurea. Such well- 
known fruits as pears, apples and peaches are classed as poisonous, 
as the seeds contain hydrocyanic acid and benz-aldehyde. The 
seeds and kernels are not the portion of these fruits which are 
eaten, but you can eat a limited amount of these parts with 
impunity. Yeast is considered poisonous on account of the 
alcohol produced by the action of its enzymes on sugar in solution. 
The alcohol is poisonous, not the yeast plant. Raspberries and 
blackberries are classed as poisonous, as there are several reported 
