MIND IN EVOLUTION 537 



simpler emotions and affective states, and our desires and 

 volitions. 



If birds, for instance, have no genuine joyousness, they 

 make at times such an extraordinarily good imitation of it, 

 that a statement of the apsychic theory gives one a disagree- 

 able impression that if this be accurate, then we are living 

 in a conjuring show. 



" Tis the merry nightingale 

 That crowds and hurries and precipitates 

 With thick fast warble his delicious notes, 

 As he were fearful that an April night 

 Would be too short for him to utter forth 

 His love-chant, and disburthen his full soul 

 Of all his music." 



Is this good poetry and bad science ? Is the joyousness 

 only in " the raptured ear of men ", or has the nightingale 

 really a full soul ? 



The critic says: But if the nightingale, why not also 

 the cricket and other insect-instrumentalists ? Perhaps the 

 best answer would be " Why not ? " ; but we are inclined 

 rather to point out that the bird has a highly developed 

 brain, not on the same line or level as that of higher mam- 

 mals, but still a fine ' big brain ', which may be reasonably 

 credited with the possibility of a stream of l inner life ' 

 fuller than is likely to flow in any representative of the ' little- 

 brain ' line of evolution. 



The critic again intervenes, pointing out that these nerve- 

 storms of excitement are due to the liberation of internal 

 secretions, and that they may be induced by injections and 

 by dieting. That of course is the physiologist's business, 

 to work out the series of metabolic happenings ; but our point 

 is that in the cases which are experimentally open to us, 



