146 PROCEEDINGS OP SECTION B. — SUB-SECTION, PHARMACY. 



whicli can be followed for the preparations of official articles ; the 

 legitimate sphere of the manufacturer is limited to the produtiou of 

 efficient galenicals in accordance with the quantities and methods 

 therein stated. All alterations of strength and dosage are questions 

 for the pharmacologist and the physician. It is clearly necessary, 

 however, to conform the activity of preparations of these potent and 

 imperfectly understood drugs by the best means available. The 

 reliability of action of those of our products which belong to this class 

 is insured by expert selection of raw material, proper methods of prepa- 

 rations and scientific physiological testing by specialists working 

 independently of the manufacturing departments. 



The strength of preparations of the digitalis group is checked by 

 their action on the isolated mammalian heart ; those of ergot by their 

 action on the isolated uterus of the rabbit. While these and similar 

 processes of estimation require the skill of a trained physiologist and 

 elaborate apparatus to carry out I believe them to be of more value 

 than the standardization to a definite lethal dose. 



(3) Where the activity of the drug is recognised to depend on 

 some definite active principle or principles which can be chemically 

 assayed, much attention is now given to this estimation, and wherever 

 possible, preparations are so standardized ; but it is first necessary to 

 establish the fact that the drug depends for its activity on the particular 

 standard to be adopted, and that the method of estimation will be 

 accurate in the hands of various workers. We have learned from this 

 work that it is not always possible to judge the value of a drug by its 

 appearance, as often clean bold roots or leaves, true to official descrip- 

 tion, are found to be almost devoid of active principle, whereas a sample 

 which the eye would reject is rich in this respect. 



Class "B " {Essential Oils). — These adapt ^themselves particularly 

 to adulteration, and more especially require a 16ng experience in their 

 valuation. So many chemists have devoted themselves to the analysis 

 of this class of material, that it is often difficult to reconcile the opinions 

 of experts, and this is made the harder by the introduction and deli- 

 berate addition of clever synthetic adulterants at the source of supply. 

 It has been said that an experienced eye and nose is as good a test 

 for the purity of an essential oil as any analytical process of estimation. 

 Though this may be an exaggeration, it is important to bear in mind 

 that any data adduced from analysis should be checked by the appear- 

 ance and odour of the oil under examination. 



The common tests employed are specific gravity, solubility, optical 

 reaction, refractive index, estimation of phenol, alcohol, or estfer, 

 as the case may be, and, where the above are inconsistent or not con- 

 cordant with previously observed results, fractional distillation and 

 examination of the separate fractions obtained. 



