Abstract
In the course of our investigation of the body righting reflexes in the fowl, a detailed report of which will appear shortly, we had one animal which as a result of a cranial operation assumed a peculiar posture at certain times. It would keep its head down and tail up, so that the long axis of the body was at an angle about 60° to the horizontal. When in such a condition, the animal invariably walked backward and continued to do so till it would hit the wall of the room. But when it kept its head in a normal position it could and did walk forward.
In order to find out the mechanism of this phenomenon we studied a number of normal Leghorn and Sebright Bantam fowls in which the lower portion of the neck was kept flexed upon the trunk by means of a gauze bandage. We found that these animals, without exception, in attempting to move walked backward. After the bandage was removed they immediately returned to the normal method of progression. Such test could be performed repeatedly on the same animal with similar results.
To determine whether this retrogression was not due to voluntary movements of the nature of escape reaction, we performed these tests on the decerebrated fowl. The results were the same as in normal animals, indicating that this phenomenon is of a reflex nature (forced movement).
We canclude, therefore, that normal progression in the chicken is dependent upon the posture of the neck, or the tonic state of the neck muscles. This ability is lost as soon as the posture of the neck is changed (neck ventroflexed upon the trunk), and progression is replaced by retrogression.
Get full access to this article
View all access options for this article.