62 STELLA BURNHAM VINCENT 



probably be subtracted from each of the average number of 

 trials in learning. If this were done, there would be but little 

 difference between the normal and the anosmic groups. There 

 is also little difference between the anosmic animals with vib- 

 rissae and those without, so far as the number of trials goes, 

 but there is a marked difference in the average time per trial 

 and here they also compare unfavorably with the normal animals. 



The anosmic animals were much less active than the normal 

 animals. They tended to grow heavier and the muscular tonus 

 had sensibly decreased. One can easily see therefore why the 

 time per trial was lengthened; but as the rats were always kept 

 at the problem until they succeeded in entering the food box 

 there was no reason why these rats should not have learned the 

 problem, as they did. 



Olfaction, no doubt, is the guiding sense of rats in seeking 

 food, the sense which excites, quickens and controls such an 

 activity. Take this away and there remains a less active, more 

 inert animal whose initiative in this respect is at a lower level. 



As has been said before, the entire purpose of a sense is not 

 to give knowledge. Indeed, one may easily conceive, in the 

 lower animals particularly, that this is the lesser function. Sen- 

 sation is a stimulus to activity, not necessarily to a particular 

 activity but to general activity. The functioning of one sense 

 may be entirely dependent upon the results of the activity of 

 other senses, so intimately are their neural systems correlated. 



If olfaction is the keenest of the higher senses of this animal, 

 its loss would probably affect even the strength of the sensation 

 of hunger by depriving it of those elements of odor which pre- 

 cede all satisfaction of the appetite and give food most of its 

 flavor, in other words by robbing food of its strongest and most 

 intimate associations. 



We should expect then, not that the anosmic animal might 

 not learn this problem, but that lacking the incentive of certain 

 strong associates, lacking the initiating peripheral stimulus to 

 this particular act, and feeling the loss of general excitation 

 caused by the cutting off of a mass of sensuous stimuli, response 

 would be more slow — and slower still in animals which were 

 further crippled by the loss of their vibrissae than in those 

 where these aids to learning were still intact. 



