ACCIDENTS BY RAIL AND SEA. 195 



color. But, as we have seen, each kind of color-blindness follows laws 

 as fixed as the normal sense. Such a stratagem will not fail to violate 

 them, and the individual will be caught in the very act. 



But there is absolutely nothing which opposes the supposition that 

 this individual may have a certain knowledge of the nature of color- 

 blindness, or, at least, that he may have an idea of its regularity with 

 regard to the confusion of colors. He may have studied the proofs we 

 have cited, and, owing to the exercise and observation of the color-blind, 

 he will know how to perform them in a manner suitable to the object in 

 view. The examiner has always, however, the choice of other sample 

 colors, and the Berlin wool method affords a large choice. If that does 

 not sufiBce, and the individual has learned from the truly color-blind 

 to classify the whole collection of wool according to their chromatic 

 sense, that is to say, that he can stand the trial according to Seebeck's 

 method, and if he is so thorough in his part that there is no means of 

 making him depart from it by abrupt or contradictory questions, the 

 examiner may employ for the examination a number of other known 

 methods, but probably unknown to our individual. It must not be for- 

 gotten here that it is generally easier to discover faults committed by 

 others than to avoid being guilty of them one's self, and one must be 

 profoundly familiar with his borrowed part not to be guilty of inconsist- 

 encies. With regard to feigning a certain kind of color-blindness, we 

 know by our experience with regard to this, that it is a very difficult 

 thing, and scarcely ever succeeds before an attentive and experienced 

 examiner. All these circumstances are advantageous for the examiner, 

 but his superiority is not limited to this. For if it should happen — an 

 extremely improbable thing — that a i)retender were familiar with all the 

 known tests and methods, and besides had not less practice than talent 

 in executing them as accurately as the color blind, the examiner has, 

 nevertheless, the power of inventing, owing to his special knowledge, 

 new tests, and of var;ying those already known. 



Besides the precaution, which must not be neglected, of conducting 

 the examination in the presence of expert and competent persons, there 

 is an especial means, which, while being certain of preventing all frau- 

 dulent attempts, judges the accused in the usual manner, that is, by the 

 testimony of two persons. These two witnesses should be two color- 

 blind of the same kind as that feigned by the examined. If these two 

 individuals are first subjected separately and independently of each 

 other and the pseudoco\or-hVind, to the same trial as he, let the results 

 be noted down carefully, and then the whole three together, and it will 

 then soon be seen how the case stands with one individual. The two 

 color-blind will in this manner give the necessary testimony without 

 resting upon the discretion of the examiner. This manner of proceeding 

 must, however, be employed with caution and discrimination, as the 

 conformity between two color-blind of the same class is not absolutely 

 perfect in every respect. The result must, therefore, always be made tv 

 harmonize by the explanation of the examiner. 



