THE TELEPHONE AND HOW IT WORKS. 559 



taken even in weak doses it causes restlessness and anxiety, a sort of 

 feverish activity altogether different from the indolent activity of 

 opium. Under the action of opium the will seems to be lulled to 

 sleep and the imagination runs riot. But under the influence of coffee 

 the imagination is hardly stimulated at all, while there does appear 

 to be excitation of the will. Did I not fear being suspected of hav- 

 ing a theory to defend, I should say that the faculties of will and 

 consciousness seem to be superexcited : there is, as it were, a constant 

 strain on attention and memory, whereas in the case of alcohol, hash- 

 eesh, and opium, there is a relaxing of attention. Hence coffee pro- 

 duces a true intoxication that fatigues one far more than does the 

 somnolent intoxication of opium, but it leads to the same result. In 

 striving to do too much, the mind does less : under stimulation the 

 will is impaired ; and the perfect equilibrium of the mental faculties 

 is disturbed as well by excess as by defect of will. 



Coffee is said to produce cerebral anaemia, while opium and alco- 

 hol cause congestion ; but this theorv still needs confirmation. Nev- 

 ertheless, the part played by coffee in general nutrition is very well 

 understood. It retards organic combustion, and hence it is an aliment 

 cTepargne a food-stuff that effects a saving of other food-stuffs. In 

 the normal state there is always going on within our tissues a multi- 

 tude of chemical actions, the final result of which is heat-production 

 and liberation of carbonic acid. This carbonic acid passes into the 

 venous blood, and the venous blood, on reaching the lungs, parts with 

 its carbonic acid. Thus the quantity of the carbonic acid is, to some 

 extent, the expression of the nutritive activity. Now, on taking 

 coffee, though no greater quantity of oxygen be inhaled, and without 

 increasing the ration of food, the quantity of the carbonic acid is re- 

 duced, and yet the amount of force is not lessened. As illustrating this 

 doctrine, it is usual to cite a fact observed among Belgian miners, 

 who can perform a considerable amount of work almost without food, 

 their strength being maintained solely by the absorption of a large 

 quantity of coffee. Hence coffee is a food-stuff which moderates 

 nutrition by lessening the activity of the chemical transformations 

 incessantly going on within the tissues. 



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THE TELEPHONE AND HOW IT WORKS. 



By GEORGE M. SHAW. 



AMONG the innumerable uses of electricity none is more remark- 

 able than its employment for the transmission of sound. The 

 ultimate mystery of the action we cannot, of course, undertake to 

 explain, but the mechanism by which it is produced is by no means 

 difficult to understand. 



