10 
should be remembered that at least some of this literature is recorded 
in journals and periodical publications that can not themselves be 
accurately classed as belonging to the literature of 1905 ; thus many 
of the reviews consulted, while they deal with the literature for 1905, 
themselves belong to the literature of the year in which they were 
published. 
Many of the ideas and opinions herein presented are manifestly 
impracticable, but are nevertheless suggestive, and the compilers have 
not considered themselves justified in ignoring or eliminating them. 
Old and previously discarded ideas are frequently revived as new 
discoveries. Such alleged discoveries should be considered with an 
added degree of conservatism, as the very fact of their having been 
previously advanced would suggest that they have evident short- 
comings. in some respect at least. 
As noted before, it would be manifestly impracticable to abstract 
at length all of the really important contributions bearing on the 
material contained in the U. S. P.. and it has frequently been found 
necessary to refer to even the more important articles in an extremely 
brief way. This brevity, it is hoped, will have the advantage of 
suggesting the need of consulting the original article itself. 
So far as it has been practicable the original article has been con- 
sulted and is directly referred to. In the many instances where this 
has not been possible or practicable an effort has been made to quote 
the most readily accessible reference that is sufficiently comprehensive 
to be of value as indicating the intent as well as the content of the 
original article. For the medical literature the compilers have con- 
fined themselves largely to several well-known medical journals, and 
to a review of the Index Medicus for such additional references as 
might be of service in indicating the use or the possibilities of official 
substances. In this connection it may be of interest to point out that 
several homoeopathic and eclectic medical journals have been re- 
viewed, primarily to record such suggestions as they might have to 
offer, and secondarily to demonstrate the evident widespread use of 
official articles by the followers of the several sectarian schools of 
medicine. 
In the main the arrangement of the material presented closely 
follows that originated by the late Charles Pice, though it was thought 
inadvisable to follow the abbreviations used by him or to confine the 
review to the journals included in the earlier numbers of the “ Digest 
of Criticisms.'’ 
For the abbreviations of the journal titles it was thought advisable 
to follow very largely the abbreviations of titles of medical periodicals 
employed in the Index Catalogue of the library of the Surgeon- 
General’s Office and in the Index Medicus. These abbreviations, 
while far from satisfactory, are the most generally used, certainly the 
