December 15, 1922] 



SCIENCE 



677 



field of genetics. The facts were observed un- 

 der the following conditions. As a part of our 

 method, we found it necessary to rotate white 

 rats day and night in small revolving cages 

 over a period of several months. The cylindri- 

 cal cages, less 'than a foot in diameter, were ro- 

 tated in a horizontal plane, some at sixty and 

 others at ninety times a minute. Several 

 months after this series of continuous rotations 

 began, a part of the subjects were removed 

 from the rotating cylinder (a) in order to make 

 observations on their behavior subsequent to 

 their long continued rotation, and (b) in order 

 to make room for litters which were born from 

 time to time within the cylinders. Several 

 weeks (the time has varied from individual to 

 individual) after these first subjects had been 

 removed from the rotating cylinders, it was 

 discovered that permanent changes in bodily 

 movement and posture had taken place. The 

 most striking changes were (a) circular move- 

 ments about the nest, usually in the direction 

 of the long eonitinued rotation, and (b) a de- 

 cided turning or twisting of the head to the 

 rig'ht or to the left. It was discovered, more- 

 over, that these changes in posture were oc- 

 casionally accompanied by swellings and dis- 

 charges from the region of the ear, and more 

 frequently, by decreasing toodily tonicity and 

 finally by death. Further search revealed the 

 fact that this state of "disequilibration" was 

 accompanied by important changes in the 

 character and in the duration of the ocular 

 movements following short rotation periods (20 

 turns in 10 seconds). 



Before the appearance of this state of "dis- 

 equilibration," a few of the subjects with a long 

 history of rotation were mated with other ro- 

 tated and unrotated individuals solely for the 

 purpose of adding to our experimental stock. 

 Curiously enough, however, individuals began 

 to appear in successive generations presenting 

 the same types of disequilibration observed in 

 the parents. That is to say, rotated individuals 

 mated weeks after having heen taken from the 

 revolving nests gave offspring a part of which 

 were disequilibrated in the same manner as 

 their parents. Subjects of this kind have c^du- 

 tinued to appear at various intervals during 



the past two years. They have even toeen dis- 

 covered in the third generation after rotation. 

 Up to this time about sixty disequilibrated in- 

 dividuals have ibeen counted in a total popula- 

 tion of approximately five hundred. 



Unfortunately, the demands of the experi- 

 ments upon equilibration made it impossible to 

 investigate adequately the genetic implications 

 involved in these materials. Nevertheless, the 

 facts as such were considered striking enough 

 to warrant their presentation at a meeting of 

 the Society of American Naturalists in 1921. 

 The questions and suggestions received at that 

 time have led to the conclusion that the biologi- 

 cal aspects of the problem should be established 

 and that definite attempts should be made to 

 discover (a) whether the stock in our lahora- 

 tory may not have given one or more mutations 

 or segregates which, in turn, ibecame the pro- 

 genitors of the curious individuals still appar- 

 ent; (b) whether an experimental method of 

 modifying the function of an important organ 

 has been accidentally discovered; and (c) 

 whether actual inheritance of such an acquired 

 bodily change can be demonstrated. The fltrst 

 suggestion seems improbable because no similar 

 rats have appeared in a large related control 

 stock running along with the experimental 

 stock. Furthermore, the character of the dis- 

 equilibration has appeared to 'be regularly de- 

 pendent upon the direction in which the an- 

 cestors were rotated. With respect to the third 

 problem, namel3', a possible demonstration of 

 the inlieiitance of acquired vestibular changes, 

 a number of biologists have oftei^ed the sugges- 

 tion that long continued rotation may have 

 induced the production of toxins or of other 

 substances which, in . turn, operate after 

 the fashion of the lens anti^bodies, recently de- 

 scribed by Guyer and Smith. 



It seems desirable, then, to institute a new 

 series of rotations with a new stock and to use, 

 as well, other means of inducing disturbances 

 in the semicircular canals so that more reliable 

 evidence for or against the apparent eases of 

 inheritance in our own stock may be discovered. 

 It is also desirable to know what morphological 

 and structural changes have taken place in the 

 vestibular areas subsequent to long-continued 



