156 Prof. F. O. Guldberg on Movement in a Circle 



life have surely been struck by the readiness with which 

 animals belonging to the same family or community find each 

 other again, after having separated voluntarily or under 

 compulsion. Indeed, even newly hatched or new-born young, 

 which one surely cannot easily suspect of having a fully 

 developed memory for places or any acquaintance with the 

 locality, and as to which it is quite impossible to imagine 

 that they are already in possession of the full use of their 

 senses, nevertheless again discover, apparently with the 

 greatest ease, their parents, brothers and sisters, or com- 

 panions, even when they have been separated from them for 

 so long a time or by so great a distance tliat their sensory 

 powers are inadequate to bring them into direct communica- 

 tion one with another. 



For liie in a state of nature has furnished us with a series 

 of observations, showing that the higher animals, at all events 

 under circumstances in which their senses do not act normally 

 or perfectly, or when they are prevented from bringing them- 

 selves into communication one with another by aid of their 

 senses, seek and find each other again in such a manner that 

 they return to the spot where they were separated or where 

 their senses corresponded for the last time. This ordinary 

 and necessary returning of animals to the spot where they 

 were separated must, as I shall show, be of a double nature, 

 namely both instinctive as well as physiological, since 

 meeting takes place by two difterent methods, either in con- 

 sequence of the animals by aid of their senses seeking and 

 finding their way back to the sj)ot where they separated, 

 or by their making without the aid of their senses a circular 

 movement, which necessarily also leads them back to the 

 place of separation. Kow, in order to come to a clear under- 

 standing as to the nature of this circular movement, as to 

 what must be the basis or cause of the instinctive pheno- 

 menon in question, 1 have instituted, in conjunction with my 

 fellow-worker Prof. G. A. Guldberg, a series of physiological 

 experiments whereby, by depriving the subjects of the experi- 

 ments of their senses, we have succeeded in compelling them 

 to make a circular movement of this kind. This movement 

 in a circle is certainly to be regarded as having a physiolo- 

 gical origin, and as tiie immediate cause we assume a func- 



nuthor proposed in a loss coiuplete form to liis brollier. Prof. G. A. Guld- 

 berg, wlio subsequently beiame a fellow-worker, especially as regards the 

 morphological and jibysiological portion of the study. With reference 

 to the actual evidence which has been collected, this will be laid before 

 the scientific world in detail at an early period, so soon as time and oppor- 

 tunity permit. 



