130 THE PRACTICAL PIGEON KEEPER. 



across the back. It is evidently a convulsive muscular spasm 

 of some kind, and this is the predominating feature of epilepsy, 

 which we also know may be excited by many causes. Now it 

 is wjbII known that good Birmingham " rollers," if in descending 

 they strike or come in contact with anything, such as a chimney, 

 are very often converted into what are called " mad " Tumblers, 

 v/hose tumbling is perfectly uncontrollable. The analogy between 

 these and the poor Indian birds lyhich roll over and over when 

 shaken by the neck or tapped on the head can easily be seen. 

 It has also been observed that " house " Tumblers wUl often 

 show a perceptible dread of the performance, sitting for hours 

 on some point and not daring to leave it, and trying to hide 

 away from the owner, whom they know as making them attempt 

 the task. It is also known that an epileptic condition is most 

 strongly hereditary, and it is easy to understand how it may 

 have arisen in confinement. The mere catching of pigeons is 

 likely to produce such a condition in individuals, and all birds 

 in partial confinement aie apt to develop a u.^rvous irritability 

 not natural to them. In this way it is easy enough to understand 

 how tumbling may have been first acquired, and then developed 

 and transmitted. 



The probability of this hypothesis appears more strong when 

 some other circumstances are considered, though some of them 

 have even been urged as objections to it. It has, for instance, 

 been asked why tumbling is confined to one branch of the 

 pigeon family. The reply is that it is not so, strictly speaking. 

 Mr. Kesteven found a pure Antwerp cock which tumbled, and 

 some other stray inUividuala have been reported; and the 

 Oriental Rollers, to be presently mentioned, show us another and 

 distinct famUy remarkable for tumbling. It is also said that 

 there appears no exciting cause for the convulsive attacks which 

 it is supposed constitute tumbling ; but it is obvious that either 

 rapid ascent in the air, or the quickened circulation caused by 

 fl3dng, would be abundantly capable of supplying the necessary 



