154 POWDERED VEGETABLE DRUGS 



A GENERAL METHOD FOR MAKING QUANTITATIVE MICRO - 



ANALYSES OF VEGETABLE DRUGS AND RELATED 



SUBSTANCES 



Several special microanalytical methods (qualitative as well as 

 quantitative) have already been given. Attemps have been made 

 from time to time to develop quantitative micro-analytical methods 

 which might be generally applicable, notably by Chamot, Meyer, 

 Hanausek, Weinzierl, Konig, Vogel and others. These quantitative 

 methods are largely based upon the fact that certain tissues and tissue 

 elements are quantitatively fairly constant in plant organs and plant 

 parts and in the various manufactured plant products found upon the 

 market. For example, mature ginger contains a fairly definite per- 

 centage of starch. Green apples contain considerable starch whereas 

 ripe apples contain only a trace of starch. Belladonna roots gathered 

 too early in the season are deficient in starch. Old thick cinnamon 

 bark is deficient in bast. Cloves contain no sclerenchyma cells whereas 

 clove stems are rich in this tissue. The chief difficulty in the way of 

 formulating definite working methods is the lack of available data 

 upon which to base such methods. For example, if we had a record 

 of the starch content of ginger, of the apple, of belladonna root, of 

 aconite root, of colchicum corm, etc., for each month of the growing 

 season, then we could readily use the starch factor in determining the 

 percentage of the articles gathered green or too early in the season. 

 If we had a complete morphologically descriptive record of the develop- 

 ment of the pollen grains in the insect flowers, we would then be in a 

 position to determine quantitatively the amount of overripe flowers 

 used in a given insect powder. In other instances it is possible to 

 work out on the spot the necessary data for each quantitative analysis; 

 as, for example, in the estimation of the percentage of stems in cloves, 

 the percentage of black pepper refuse in black pepper, the percentage 

 of stems in senna leaves, etc. Patience and a willingness to work are 

 the essentials to success in the working out of such methods. As the 

 details for the quantitative microanalysis of any one vegetable sub- 

 stance are fully and accurately worked out, the figures obtained should 

 be carefully and permanently recorded for the benefit of those who 

 follow after. 



The chief source of error in making quantitative microanalytical 

 determinations, of the kind here described, is the fact that while the 

 different tissue elements and cell contents are fairly constant in tissues 

 of the same kind (in the same relative position and of the same age and 

 seasonal growth), we have no usable records of the quantitative tissue 



