. Public health laboratory work, including methods employed in bacteriological research, with special reference to the examination of air, water and food contributed . Fig. elder-leaf (after Bell). Fig. willow leaf (after Bell). reach this country—rarely takes a dangerous form hy-gienically, and has of late years very much commonest practice, at the present day, is theadmixture with large quantities of either foreign leavesor of tea leaves which have been already infused. Howcan the former practice be best detected ? The micro-scope affords the readiest and truest
. Public health laboratory work, including methods employed in bacteriological research, with special reference to the examination of air, water and food contributed . Fig. elder-leaf (after Bell). Fig. willow leaf (after Bell). reach this country—rarely takes a dangerous form hy-gienically, and has of late years very much commonest practice, at the present day, is theadmixture with large quantities of either foreign leavesor of tea leaves which have been already infused. Howcan the former practice be best detected ? The micro-scope affords the readiest and truest means ! A verylow power will suffice to disclose the structural charac- TEA. 389 ters of the various leaves, and fortunately the tea leafpossesses characteristics which mark it out from thoseof any other plant: the differences, however, are slight,and may be readily over-looked, especially when theleaves of the elder, willow, and sloe—which are thosemost commonly employed—are selected to serve thepurposes of sophistication ; there is much less difficultyin detecting the presence of beech and oak leaves, whenthese are
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