Mabch 19, 1909] 



SCIENCE 



457 



" shady " practises carried out in the shops of 

 the ancient druggists (tenebrse officinarum). 



In the long list of tests, which Pliny enu- 

 merates for detecting the various forms of 

 adulteration practised in his time, by far the 

 greater number relate to the use of our 

 simplest sense perceptions, such as taste, smell, 

 color, feel, brittleness, etc. The ancients 

 guided by such perceptions were unquestion- 

 ably better judges of the purity of many 

 articles of food than we are to-day. Pliny in 

 fact, makes such a fine classification of tastes 

 and flavors (book 15, eh. 32) that the trans- 

 lator finds himself at a loss for suitable terms 

 in which to express the meaning. Whether 

 this indicates an over-refinement of the taste 

 perception among the Romans through the 

 influence of a long line of epicures dating 

 from LucuUus, or simply an atrophy of our 

 present powers in this respect, would be diffi- 

 cult to say. Professional tasters (book 14, 

 ch. 8) were in demand during the early days 

 of the Eoman empire to determine the quality 

 of wines, and notwithstanding our advanced 

 chemical knowledge of the score or more 

 esters which give wines their characteristic 

 bouquet, the final criterion in the judgment of 

 a wine, now as in the days of Pliny, is the 

 evidence of a skillful taster. 



But the ancients had many other means of 

 testing the purity of their commodities of life 

 than those of simple taste and smell; and it is 

 worth our while to examine a few of these, 

 for they mark in reality the first beginnings in 

 the development of the science of analytical 

 chemistry. A good illustration of such tests 

 is given under Pliny's description of Balsam 

 (book 12, ch. 54). 



Balaam in a genuine state should be quite hard, 

 but when it is mixed with gum a brittle pellicle 

 forms upon it. The fraud can also be detected by 

 the taste and when placed upon hot coals it may 

 easily be seen if there has been any adulteration 

 with wax and rosin, for the flame in this case 

 burns with a blacker smoke than when the balsam 

 is pure. In addition to these various tests a drop 

 of pure balsam, if placed in luke-warm water, will 

 settle to the bottom of the vessel, whereas, if it is 

 adulterated it will float upon the surface like oil, 

 and if it has been drugged with metopion or am- 



moniacum, a white circle will form aroimd it. 

 But the best test of all is, that it will cause milk 

 to curdle, and leave no stain upon cloth. 



Such tests as the ones cited in this quota- 

 tion show that the faculty of careful and pre- 

 cise observation was by no means neglected 

 among the ancients. 



The fiame test to which reference was made, 

 is mentioned repeatedly by Pliny in the test- 

 ing of drugs and chemicals. In some casea 

 the color and smell of the smoke were ob- 

 served, in others the color of the flame, or the 

 property of decrepitating. 



The formation of a white ring as described 

 by Pliny in his test for adulterated balsam, 

 brings up to the mind of the chemist the 

 innumerable ring tests which are made use of 

 in the laboratory at the present day, as well as 

 the host of color reactions employed in testing 

 food products, drugs and chemicals. We find, 

 in fact, that these color reactions were used 

 very extensively by the ancients, and the men- 

 tion of one or two others may have a passing 

 interest. 



Among the tests given for alum Pliny 

 (book 35, ch. 52) states that it will turn 

 pomegranate juice and nut galls black. 

 Authorities differ somewhat as to the exact 

 nature of the compound that was called 

 alumen by the Romans and crTvirTTjpia by the 

 Greeks, but all seem agreed that sulphate of 

 iron was present. The tests which Pliny de- 

 scribes are therefore nothing but the familiar 

 tannin reaction with salts of iron. 



A most interesting modification of the nut- 

 gaU test is described under the subject of 

 verdigris (book 34, ch. 28). Here a piece of 

 papyrus, which had been previously steeped in 

 an infusion of nut galls, is employed for 

 testing, the paper so treated turning black if 

 genuine verdigris is applied. This passage is 

 noteworthy, for so far as I can find it is the 

 first historical reference to the use of test 

 paper. 



In a number of instances I have found 

 Pliny to be even wiser than his modern com- 

 mentators. Pliny gives, for example, as one 

 of the tests for vinegar (book 23, ch. 2Y) that 

 it has the property of effervescing when 

 poured upon the ground. The editor of one 



