A Note on the Action of Bulbocapnine.

THE recent work of de Jong and Baruk on the experimental production of catatonia in animals by means of bulbocapnine throws light on the condition of catalepsy. The first important fact discovered is that bulbocapnine can produce effects in the higher animals corresponding to those of catalepsy in man, but cannot produce such effects in the lower vertebrates (frogs, snakes, lizards, fish), which lack a neocortex. Furthermore, as stated by de Jong and Baruk, in an animal whose cortex has been removed. bulbocapnine does not cause catalepsy. This indicates that the catalepsyproducing effect of bulbocapnine occurs through a specific action of the drug on the cerebral cortex. In fowls, which have but a rudimentary neocortex, the catalepsy is incomplete and unstable. In moderate doses bulbocapnine has the unique effect of producing catalepsy. What is the physiological process at work here'? We must assume that in catalepsy there is primarilya blocking of sensory nerve-impulses in the central nervous system. That this is so is indicated by the fact that one may stick a pin into the flesh of a cataleptic person without any visible response. Generally speaking, to obtain a change of position of a limb or of the body in a cataleptic, mechanical force must be used, whereas in a normal person a nervous stimulus such as a pinprick or a slight pressure is sufficient. The long maintenance of one position by a cataleptic also suggests a complete isolation of the motor centres of the central nervous system from external stimuli. In sleep there is also an isolation of the motor centres of the brain from external stimuli, but it is more of a partial isolation, for an individual may frequently move in his sleep from an obvious external cause. Also, the isolation of the motor centres in sleep is easily broken down by any slight stimulus which awakens the individual. The physiological process at work here is, according to Pavlov, a general inhibition of the cerebral cortex, descending to the subcortical motor centres. Catalepsy, as well as sleep, is apparently caused by a change in the cerebral cortex, and in catalepsy that change would appear to consist of a