September 10, 1886.] 



SCIEJ^CE, 



241 



alike. We thus have a means of varying one with- 

 out tlie other. The independence of the two pro- 

 cesses (distinction and choice) is further shown by 

 the fact that II. is the quickest distinguisher, 

 while III. is the most ready chooser. III. is slow- 

 est in both operations, but differs less in the readi- 

 ness of her sensibility and judgment than in the 

 alertness of her will. Perhaps an educational 

 truth with regard to the development of the mental 

 powers is hinted at hei'e. 



4. Association time, — Here our apparatus re- 

 duces itself to a clock and some slips of paper ; 

 but the number of persons involved in the experi- 

 ments must be increased from two to three. Let 

 each of the three write on the slips of paper ten or 

 twenty words, say, of one syllable each, and the 

 names of concrete things. Avoid any natural con- 

 nection between the words by not writing them in 

 the order in which they were thought of. Now 

 let I. and II. be the subjects of the experiment, 

 while III. records the time. 1°. Let I. begin by 

 calling, as soon as he hears the signal, the first 

 word on his list : hereupon II. answers by the 

 first word which he can associate with the call- 

 word, and immediately upon this calls his first 

 word to I., who in turn perforgas the association 

 and calls his second word ; and so on to the end. 

 If there are ten words on the list of each, then each 

 person has called ten words, has answered ten 

 words, and has performed ten associations. 2^. 

 Now let I. and II. each have twenty words before 

 him, and let each call a word as soon as he hears 

 the answer of the other.^ This operation will dif- 

 fer from the former only by the fact that the 

 association has been omitted. The difference in 

 time between 2° and 1° divided by 10, will give 

 the sum of the association times of I. and II. 



Now let I. and III. be the subjects, and II. take 

 the time, and the sum of the association times of 

 I. and III. will be obtained. Then get the sum 

 of the times for II. and III., and the solution of a 

 very simple algebraic ec[uation will give the value 

 of the association time of each. 



I have also used another, perhaps somewhat 

 simpler method. It differs only in that in each 

 operation one person acts as caller, and the other 

 as associater, throughout. In this way the values 

 of six equations are gotten : i. e., I. (caller) + II. 

 (associater) = ? ; II. (caller) -f- 1, (associater) = ? ; 

 and so with each pair. We then eliminate the value 

 of ' I. (caller),' 'II. (caller),' etc., by getting the 

 value of the three equations, — ' I (caller) + II. 

 (caller),' 'I. (caller)+ III. (caller),' etc., just as 

 before. The results of the two methods agree 

 very well, and one may be used as a check upon 



1 The words should be proBounced distinctly, and no 

 more rapidly than in the first operation. 



the results of the other. The effect of practice in 

 reducing the time is at first very considerable. 



It remains to be noted, that after I have ascer- 

 tained my own association time and my own call- 

 ing time, and know it to be fairly constant, the 

 work of finding the reaction time of a fourth 

 person is much reduced. We have simply to get 

 the sum of our association times and of our calling 

 times, and subtract from these my own association 

 and my own calling time. 



I will give the results of the first method, because 

 here alone is the effect of practice (in two of the 

 subjects) eliminated. The subjects are the 11. and 

 III. of our former experiments, and the times are 

 .803 and .872of a second respectively, which agrees 

 very well with .764 of a second, which is the time 

 found by Professor Wundt by the more elaborate 

 methods. The great difference between this time 

 and that necessary for a distinction or a choice, 

 shows how much more elaborate the former pro- 

 cess is. 



The methods above described leave much to be 

 desired ; but the principle upon which they depend 

 (namely, of substituting a series of reactions for a 

 single one, and of arranging the apparatus so that 

 the subject himself produces the sensations upon 

 which the distinction and choice is made) seems to 

 be the one by which the desired simplification can 

 be best accomplished. If the above account shall 

 be the means of setting others to work at the same 

 problem, and of popularizing to any extent the 

 study of experimental psychology, its object will 

 be more than fulfilled. Joseph Jasteow. 



THE HYGIENE OF THE VOCAL ORGANS. 



The experience which Dr. Mackenzie has had 

 for the past twenty-five years, as a specialist in 

 the treatment of diseases of the thi-oat, renders 

 him thoroughly competent to advise on the im- 

 portant subject of which he treats in the volume 

 before us. Additional interest attaches to his 

 utterances for the reason that during this active 

 career, the most famous singers have come under 

 his professional care and observation, including 

 Nilsson, Albani, Vallina, Patti, and a host of 

 others. 



Dr. Mackenzie well says that hygiene has a 

 positive as well as a negative side. The preserva- 

 tion of health m^ans not only that actual mischief 

 is avoided, but that the body is kept in the best 

 working order. The hygiene of the voice, there- 

 fore, must include a consideration of the best 

 methods of developing its powers to the highest 



The hygiene of the vocal organs ; a practical handbook 

 for singers and speakers. By Morell Mackenzie, M.D. 

 London, Macmillan, 1886. 12°. 



