BRAINS AND SPINAL CORDS IN ATAXIC PIGEONS 117 



less flexed and widely abducted, so that the web spaces appear 

 quite large and toes show so-called hollow-foot. They do not 

 'coo' or make any other noise. To observe the intelligence of a 

 bird is of course always difficult. So far as we can see from 

 the behavior of the birds, the intelligence seems not to be far 

 different from that of the healthy birds; they show movements 

 of uneasiness and fear, if one approaches them or tries to catch 

 them then they begin to move away as one approaches. They 

 distinguish food from uneatable objects, and show a preference 

 for the place in the cage where the body is most conveniently 

 supported. 



No bird shows a limitation to a particular kind of incoordinated 

 movement; all of them have a nodding head and neck and even 

 a swaying trunk, tipping forward and backward and falling to 

 either side. The unsteady staggering gait, tipping head, and 

 swaying trunk are the common symptoms in all affected birds 

 with of course variations in degree. A weakness of the sphincter 

 of rectum or bladder cannot be detected in any bird. 



Pigeon no. K207. Keeps body quiet; stretches the legs forward 

 and widely apart laterally, the head and neck pulled a little backward. 

 The bird tips to one side twelve to fifteen times when standing without 

 leaning against the wall or on any support. When excited the head 

 and neck move at first clonically upward, then backward so that the 

 head eventually touches the back. To coordinate this forced position 

 of head and neck the bird flaps the wings excitedly, but in vain, to 

 restore the right position. Often the bird turns a somersault backward 

 several times to regain its position. If we catch the bird by the wings, 

 we feel a strong resistance in the wing muscles when the forced move- 

 ments are occurring. No rigidity or paralysis, ho.vever, was recog- 

 nized (fig. 1). The pigeon was killed January 28, 1918. 



Pigeon no. K137. Remains on the floor with w y idely spreading legs 

 and with tail braced against the bottom of the cage. When walking 

 the bird tips to one side or the other. When excited this movement 

 occurs twelve times a minute. Usually always when two or three steps 

 are taken the bird stops and braces the tail against the floor to regain 

 its equilibrium. Reacts normally to light and sound. No spon- 

 taneous nystagmus in head or eyes. As time progressed the svvayings 

 of the body increased so that before it was killed (February 2, 1918) 

 they occurred eighteen times a minute. The legs react to touch and 

 pain, though slowly. The nails and phalanges of the toes were flexed 

 and the toes turned toward the midline of the body resulting in a sort 

 of talipes cavus or hollow foot. The tail, owing to constant use as a 



