ACCIDENTS BY KAIL AND SEA. 11) 1 



come to the assistauce of tlie other by holding above the pile one skein 

 after the other, and requesting him to say whether it resembles the color 

 of the sample or not. It will be advisable first to select the skeius that 

 a color-blind person would approve. If he is so, he will approve of the 

 selection, and the question is settled. If not, he rejects them, not with- 

 out a characteristic smile, or with an expression of wounded dignity. 

 This also enlightens us as to his chromatic sense. But even the color- 

 blind may in such a case refuse what is presented, especially if his cau- 

 tion is premeditated, and he suspects that a snare is intended. It is 

 found quite frequently that he rejects the correct shades likewise pre- 

 sented with the others. This is not the case when one, having a normal 

 chromatic sense, is slow and deliberative when subjected to the test 

 under this form. He has an eye alive to the correct colors. 



One process, in cases of this last kind, is to select false samples which 

 are placed quite near the correct one, by the side, above or below, to 

 attract the attention of the examined from the right side. It is necessary 

 so to proceed that the true sample be displaced when the others are 

 drawn out, so that the person examined may see it move. It does not, 

 however, always happen to catch his eye. The best means is then to 

 make him examine the whole, with his hands behind his back, and invite 

 him to freely make his choice. But, whatever the process, it is neces- 

 sary, in every case where one has been assisted in selecting a certain 

 number of skeins which he has found analogous to the sample color, to 

 make a rule not to conclude the trial without examining into the effect 

 of the aid accorded. It is necessary to hold in the hand the approved 

 package, and ask if he is satisfied or if he would desire any change. If 

 he approve the choice, the diagnosis is established. The same course 

 must be pursued with the defective chromatic sense, that the trial may 

 be made with or without assistance. To be thorough, the name given 

 by the color-blind to the colors in question may be likewise asked. 



In cases where any one suspected of color-blindness has remained 

 some time to see the trial of others, and where, as often happens, he 

 has remarked the samples belonging to a required green shade, he may 

 of course profit by it in his own trial. But this can be prevented by 

 furtively concealing one or two of these samples. If he seem to be dis- 

 posed to confound green and gray, it will be very easy to entrap him. 

 If we do not succeed, even when assisting him, in entraj^ping him in 

 this snare, the hidden samples may be put back into their places, to be 

 convinced that the trial is correct. 



From the above, it is seen that many artifices may be necessary in 

 our examination. It may be regarded as an advantage of our method 

 that it has at command a great variety of resources. We have by no 

 means mentioned all; and yet many who have only read this descrip- 

 tion will probably reproach us with having devoted ourselves too much 

 to details which seem to them puerile. But we believe that those who 

 have examined the chromatic sense of a great number of persons, and 

 acquired thereby considerable experience, will think differently. 



