274 NA TURE STUDIES. 



weakened in the same way and in the same degree as 

 we should judge it to be if we found that numbers, 

 dates, names, or words, which we had had occasion 

 to employ daily for years, were suddenly clean, for- 

 gotten ? Making use, as we conveniently may (though 

 we must not place too much stress on the method), 

 of the analogy between bodily and mental relations, 

 we may compare a change of the former kind to a 

 diminution of the power of acquiring some new feat ; 

 a change of the latter kind, to the sudden loss of a 

 feat already acquired and long practised. It can 

 hardly be doubted that an athlete who should find 

 himself unable to perform some new gymnastic trick, 

 which he had supposed well within his powers, would 

 not be so much struck by the circumstance, as he would 

 be if he should suddenly find himself unable to achieve 

 a feat in which he had hitherto found no difficulty. 



Let us inquire, however, whether known cases of loss 

 of memory of either kind afford any means of answer- 

 ing the question which has thus arisen. Of course, 

 those cases in which the trouble has been only tem- 

 porary, though far more numerous than those in which 

 loss of memory has been symptomatic of actual dis- 

 ease, stand far less chance of being kept on record, 

 so that we may have to consider cases of the latter 

 kind to discover the relative importance of the two 

 forms in which loss of memory may be noticed. The 

 reader must not judge from cases thus cited that 

 either class of symptoms is necessarily, or even pro- 

 bably, indicative of serious brain mischief. 



