346 ANNUAL KECORD OF SCIENCE AND INDUSTRY. 



the so-called magnetizing operation had nothing Avhatever to 

 do with the condition of the animal, and that a similar state 

 could be induced by hanging it up by a cord tied around its 

 tail. He remarked that the animal is most prone to pass into 

 this somnolence in the fall and winter, and suggested as an 

 explanation of the phenomenon that excitability of the nerv- 

 ous system of the crab is impaired, and the organs of motion 

 are consequently disturbed in their functions, when the ani- 

 mal is placed in such an involuntary and unusual position. 

 He also noticed the well-known fact that if a chicken in a 

 sitting position on a table be gently pressed with one hand 

 upon the supporting surface, the head and bill pressed down 

 with the other hand, and a chalk line drawn from the tip of 

 the bill, the fowl will remain perfectly powerless in the posi- 

 tion given to it for some time after the removal of the hands. 

 Professor Czermak found that the chalk line was not essen- 

 tial to the success of the experiment, and also performed it 

 with other birds (as swans), but did not succeed with pigeons. 

 He also ascertained that subjects least accustomed to asso- 

 ciation with man, and that seemed most unruly before the 

 experiment, pass most rapidly and soundly into the somno- 

 lent condition. This phenomenon was explained by Kircher, 

 in 1645, upon the hypothesis that the chicken imagined the 

 chalk line to be a cord holdiuGj its bill down after the finsjer 

 had been removed. As a physiological explanation, a me- 

 chanical irritation of the brain and nerves by pulling might 

 at once suggest itself. It is known that certain excitements 

 of exterior nervous apparatus will often exert a decided effect 

 on the nervous centres, the brain, and the spinal cord. This 

 is very evident in the case of a frog having its fore-legs tied 

 together to excite a portion of the nerves of the skin. It will 

 then, when placed on its back, remain perfectly powerless, 

 and only regain its activity when the cord is removed ; while 

 a frog that is free can not be made to remain upon its back. 

 There can be no doubt that this is a reflex phenomenon ; but 

 the case of the chicken may not be equally so. The peculiar, 

 unusual position of the animal may doubtless co-operate ; and 

 although the chalk line can be clearly demonstrated to be 

 unnecessary, yet there are facts that indicate that it may not 

 be without its influence in attracting and fixing the attention 

 of the fowl. It is suggested that this constrained attention 



