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nutritive results observed and recorded, or medicines being so 
administered and their physiological and therapeutic effects ob- 
served by trained experimenters, delicate apparatus often being 
employed for the purpose. This method is manifestly very diff- 
cult, ifit isto be made at all certain ; so much so that its very prac- 
ticability is only now beginning is be generally acknowledged. 
The second method is that of quantitative chemical analysis or 
e, t 
sible field of its application, especially in relation to vegetable 
drugs and medicines, is quite limited in the present state of our 
knowledge. 
The third method is the examination of the physical characters 
of the drug, especially its structure. This is the natural method 
of examining the article when entire. When it comes to us in 
the form of a fine powder, as it usually does, its examination can 
be conducted only by the aid of the microscope. The possi- 
bility of identifying the minute elements of these powders has 
been to a great extent doubted, even by many scientific people 
who should know better. Only a week ago a very prominent 
pharmacist acquaintance expressed surprise at my reference to 
this work, saying that he supposed that as yet it was mere theory. 
We have only to reflect that each of the cellular elements com- 
posing the plant is just as much a complete individual as is the 
life history. It will not then surprise us to be told that many of 
the cells of plants, properly magnified, can be recognized with as 
much certainty as can other natural objects. 
It is true that until very recently little could be done in this 
direction, but this fact was due wholly to lack of knowledge of 
methods and substances, Within the last few years, thanks to 
the services of Kraemer, Schneider, Jelliffe, Nelson, Mansfield 
and others in this country, and many foreign workers, the minute 
structure of a large part of our drugs has been made known to 
us. J do not claim to be one of the leaders in this work, but I 
have followed the investigations of these men with the greatest 
interest and profit, and I have endeavored to bring together this 
afternoon a number of ‘cases illustrating the importance of the 
