THE PRESIDENT S ADDRESS. 45 



of our common freshwater species. When they get to the length of 

 about an inch, they change into the tiny eels known as ' elvers,' 

 which swarm in thousands up our rivers. Thus the habits of the 

 Eel reverse those of the Salmon. 



I will only take one other case, the fly of the King Charles Oak- 

 apple so familiar to every school-boy. In this case the females 

 were known ; they are of course very common. But no one had 

 ever seen a male. Hartig in 1843 knew 28 sp. of Cynips, and in 

 28 years' collecting had never seen a male of any of them. He 

 and Frederick Smith between them examined over 15000 specimens 

 of Cynips disticha and C. Kollari, and every one was a female. 

 Adler, however, made the remarkable discovery that the galls 

 produced by these parthenogenetic females are quite unlike the 

 galls from which they were themselves reared : that these galls 

 produce flies which had been referred to a distinct genus, and of 

 which both males and females were known. Thus the gall-fly from 

 the King Charles Oak-apple, which are all females, creep down 

 and produce a gall on the root of the Oak from which quite a dis- 

 similar insect is produced, of which both sexes occur, and the 

 female of which again produces the King Charles Oak-apple. This 

 is not the opportunity of course to go into details, and I merely 

 mention these facts as another illustration of the surprises which 

 aw^ait us even in the life-history of our commonest species. 



Many writers have attributed to Animals a so-called " sense of 

 direction." I have attempted to show elsewhere that some species 

 of Ants and Bees certainly have none. Pigeons are often quoted, 

 but the annals of Pigeon flying seem to prove the opposite ; they 

 are 'jumped ' from one point to another. 



We know little about our own senses — how we see or hear, 

 taste or smell ; and naturally even less about those of animals. 

 Their senses are no doubt in some cases much acuter than ours, 

 and have different limits. Animals certainly hear sounds which 

 are beyond the range of our ears. I have shown that some of 

 them at any rate perceive the ultra-violet rays, which are invisible 

 to us. As white light consists of a combination of the three primary 

 colors, this suggests interesting color problems. Many animals 

 possess organs apparently of sense, and richly supplied with nerves, 

 which yet appear to have no relation to any sense known to us. 



Animals perceive sounds which are inaudible to us, they see 

 sights which are not visible to us, they perhaps possess sensations 

 of which we have no conception. The familiar world which sur- 

 rounds us must be a totally different place to them. To them it 

 may be full of music which we cannot hear, of color which we cannot 

 see, of sensations which we cannot conceive. 



There is still much difference of opinion as to the mental 

 condition of animals, and some high authorities regard them as 

 mere exquisite automata — a view to which I have never been able 

 to reconcile myself. The relations of different classes to one 



