11 
introduced for over fifty important ofiicial preparations for which no 
such requirements were made in the 1S90 Pharmacopoeia. 
Before the introduction of assay methods the pharmacist and physi- 
cian were compelled to judg'e the quality of drugs largely by their 
appearance; from this it was possible to determine in many cases 
whether medicinal plants, for example, had been collected and cared for 
in a way which would proboMy preserve their therapeutic virtues. In 
many cases, however, the physician was compelled to rely solely upon 
the therapeutic test. Great credit is due those manufacturers who 
for years have been perfecting processes of assay and placing upon 
the market preparations of definite strength of many of the most 
important drugs. 
The introduction into the Pharmacopoeia of such a large number of 
these assay processes will now insure a more general uniformit}^ in 
the purity, strength, and therapeutic action of pharmacopoeial prepara- 
tions than ever before, and the entire medical profession is under 
lasting obligations to the Committee of Revision who have labored so 
long to perfect as nearly as possible these assa}’ methods. Unfortu- 
nately there still remain a number of pharmacopoeial preparations 
for which no definite method of chemical analysis or assa}" has been 
devised. Among these may be mentioned the Serum Antidijjlitheri- 
curn^ alread}^ referred to. Another group embraces certain galenicals, 
the active principles of which are as yet either not sufficiently known 
or are incapable of isolation and assay by present methods. Although 
care in the selection and in the manufacture of the materials will in 
many cases insure preparations of therapeutic value, yet, for the careful 
standardization of such, recourse is had to physiological methods; but 
physiological methods of standardization were specificalhA3arred from 
the Pharmacopoeia by the Pharmacopoeial Convention of 1900. The 
reasons for this are obvious; assay processes introduced into the 
Pharmacopceia are such as every well-equipped pharmacist is able to 
apply. It is not to be expected, however, that even the best-equipped 
pharmacist should have the theoretical knowledge, the technical 
training, and the material facilities for biological and physiological 
investigations. Recognizing the increasing demand for standard- 
ized preparations, certain manufacturing establishments have been 
equipped not only with pharmaceutical and chemical laboratories of 
the most approved type, but with biological laboratories as well, the 
work and products of which are a credit alike to commercial enterprise 
and to genuine scientific progress. 
5. Purity rubric. — Whenever practicable a minimum degree of 
purit}" has been fixed and requirements established which exclude 
objectionable impurities. 
6. Poses. — The Pharmacopoeial Convention instructed the Com- 
mittee of Revision ‘‘to state the average approximate (but neither a 
