CATALEPSY IN PHASMIDAE SCHMIDT. 503 



But while these superficial observations show a strong similarity 

 between the quiescent state of Carausius with the symptoms of 

 catalepsy in man and higher vertebrates, greater study of details 

 proves complete identity between the two categories of phenomena. 



Closer examination shows first that the muscles of the resting 

 insect are shortened and taut ; femora and tibiae, for instance, are at 

 a certain angle to each other, to change which force must be 

 applied, when again a definite angle is formed which is retained for 

 a long time. This changing of angles, however, must not exceed the 

 limits of the elasticity of muscles and ligaments. But the muscles 

 are not as set as they are in tetanus. The muscles are plastic and 

 yielding. 



These properties of the muscles exactly characterize the cataleptic 

 state of man and vertebrates (hare, hen, and frog). The eminent 

 French physiologist, Ch. Richet, thus describes the cataleptic state of 

 the muscle : " A muscle in catalepsy is slightly elastic, so that little 

 strain takes it out of the original position ; at the same time it is not 

 quite elastic enough so that, taken out of the original position, it 

 does not return to it and retains the new position indefinitely. Just 

 as a piece of wax or butter retains impressions made in it, so the 

 cataleptic muscle is changed by the mechanical influences to which it 

 is subjected." A contracted muscle differs from the cataleptic in 

 that the latter " is incomplete contraction. A tetanic muscle is very 

 similar to a cataleptic. In both, voluntary shortening of the muscle 

 is impossible, and of its own accord the muscle does not w^eaken ; the 

 difference is only that in catalepsy the shortening of the muscle is 

 moderate and can be overcome by slight mechanical force, while in 

 tetanus no force can overcome it." Thus the difference between con- 

 traction and catalepsy is quantitative only, catalepsy is incomplete 

 contraction-. 



As a further characterization of catalepsy Richet gives " absence 

 of fatigue; the contraction of the muscles, however taut and pro- 

 tracted, produces no sensations of f atigi:e, so that a muscle contracted 

 remains so for many hours, days, and months even, producing no ex- 

 haustion or fatigue in the subject." This is true of the phasmids. 

 It can not be said they do not feel tired, but this is established by 

 the fact that they retain most difficult poses during long stretches of 

 time. They also are as active at the end of a cataleptic fit as before 

 it. Catalepsy is also characterized by the absence of feeling — ^" an- 

 aesthesia " — the subject may be pricked, cut, scorched without react- 

 ing. Experiment proves this also true of cataleptic phasmids. 



The author snipped one-quarter of the antenna of a resting phas- 

 mid. Sometimes there is slight shiver, due to shock, probably, but 

 otherwise the insect remains motionless without even changing pose. 

 Several minutes later another one-fourth antenna was cut; result 



