222 THE POPULAR SCIENCE MONTHLY. 



passages that I wish the reader to specially compare with the preced- 

 ing quotations from Johnstone : " In reference to nutrition, we may 

 say that tea increases waste, since it promotes the transformation of 

 food without supplying nutriment, and increases the loss of heat 

 without supplying fuel, and it is therefore especially adapted to the 

 wants of those who usually eat too much, and after a full meal, when 

 the process of assimilation should be quickened, but is less adapted to 

 thep>oor and ill-fed, and during fasting." He tells us very positively 

 that " to take tea before a meal is as absurd as not to take it after a 

 meal, unless the system be at all times replete with nutritive material." 

 And, again, " Our experiments have sufficed to show how tea may be 

 injurious if taken xoith deficient food, and thereby exaggerate the evils 

 of the poor " ; and, again : " The conclusions at which we arrived 

 after our researches in 1858 were that tea should not be taken without 

 food, unless after a full meal ; or with insufficient food ; or by the 

 young or very feeble ; and that its essential action is to waste the sys- 

 tem or consume food, by promoting vital action which it does not sup- 

 port, and they have not been disproved by any subsequent scientific 

 researches." 



This final assertion may be true, and to those who " go in for the 

 last thing out," the latest novelty or fashion in science, literature, and 

 millinery, the absence of any refutation of later date is quite enough. 



But how about the previous scientific researches of Lehmann, who, 

 on all such subjects, is about the highest authority that can be quoted ? 

 His three volumes on " Physiological Chemistry," translated and re- 

 published by the Cavendish Society, stand pre-eminent as the best- 

 written, most condensed, and complete work on the subject, and his 

 original researches constitute a lifetime's work, not of mere random 

 change-ringing among the elements of obscure and insignificant or- 

 ganic compounds, but of judiciously selected chemical work, having 

 definite philosoj)hical aims and objects. 



It is evident from the passages I have emphatically quoted that 

 Dr. Smith flatly contradicts Lehmann, and arrives at directly contra- 

 dictory physiological results and practical inferences. 



Are we, therefore, to conclude that he has blundered in his analy- 

 sis, or that Lehmann has done so ? 



On carefully comparing the two sets of investigations, I conclude 

 that there is no necessary contradiction in the facts; that both may 

 be, and in all probability are, quite correct as regards their chemical 

 results ; but that Dr. Smith has only attacked half the problem, 

 while Lehmann has grasped the whole. 



All the popular stimulants, refreshing drugs, and " pick-me-ups " 

 have two distinct and opposite actions — an immediate exaltation 

 which lasts for a certain period, varying with the drug and the con- 

 stitution of its victim, and a subsequent depression proportionate to 

 the primary exaltation, but, as I believe, always exceeding it either in 



