BIOLOGICAL PRODUCTS 267 



vision. These tests, as carried out in the laboratories of Parke, 

 Davis and Co., may be outlined as follows: 



I. Standardization. 



1. Potency. Determining the number of units per cc. 



2. Activity. Ascertaining the power to produce the desired results. This 

 is simply a check on the potency test. 



3. Serum Tests. In some of the biological products certain tests are made 

 to determine the difference between anti-sera and the normal serum of the 

 same species. 



II. Safety Tests. 



1 . Freedom from bacterial contamination in those products which are sup- 

 posedly free from living germs. 



2. Determining the purity of the cultures in those products which are com- 

 posed of pure cultures of a given kind of germ. 



3. In case of products which are supposed to contain dead bacteria only, 

 tests are made to determine the absence of all organisms capable of 

 multiplying. 



In order to test biological products as to the absence of viable 

 or living organisms, about 2 cc. of the sample is cultured under 

 aerobic and anaerobic conditions. To determine the purity of a 

 product containing living bacteria, cultures are made in suitable 

 media and these are carefully studied as to specific cultural char- 

 acteristics and appearance under the compound microscope. 



For the purpose of standardizing the products, a well-equipped 

 ^laboratory is necessary, including the necessary experimental 

 animals. The full routine followed out in the laboratory of the 

 factory need not be carried out in the regulatory drug laboratory. 

 In most cases the work will consist of making animal inoculation 

 tests to determine the potency of the marketed article in order to 

 ascertain whether or not it possesses the properties claimed for it. 

 [n some instances it may be necessary to determine the presence 

 of toxic ingredients. Perhaps the most likely tests will be those 

 which come under the head of potency and safety tests. For the 

 present purpose the above outline will no doubt suffice. As to 

 what methods may become desirable and necessary, only time 

 and further experience will indicate. 



