476 PHYSIOLOGY. 



But, to obtain a positive result, Rengger now made his experiments 

 immediately upon the brain itself. He first laid it bare, and by some 

 further incisions he removed it, and carefully closed the wound. The 

 creature made, even during the operation, several convulsive motions of 

 the whole body, which continued for a space of time after the removal of 

 the brain, but then ceased, upon which the body appeared as in a para- 

 lysed state ; the caterpillar could no longer eat, could no longer walk, but 

 struggled first forwards and then on one side or the other ; the peris- 

 taltic motion of the stomach disappeared, and only here and there did a 

 fasciculus of muscles still catch. But, just as in the preceding expe- 

 riments, the muscles retained their individual irritability, and reacted 

 upon the application of stimulants. Rengger, that he might avoid 

 the hemorrhage and other violent effects which necessarily occur in 

 such operations, wounded and removed the brain with a red hot needle, 

 but still the loss was accompanied by the same phenomena. 



273. 



Treviranus' observations *, however, do not harmonise with the con- 

 clusion deducible from the preceding communications of an important 

 preponderance of the brain over the other ganglia. He saw a Carabus 

 granulatus after its head was cut off still run about and seek a way to 

 escape by ; even after the removal of its prothorax the creature exer- 

 cised its former voluntary motions, until, upon the removal of the meso- 

 thorax, they died away in irregular catches. The head of Tabanus 

 bovinus was cut off, and it was then laid upon its back, when it made 

 every possible endeavour to resume its usual position, and laid hold of 

 a pencil offered it, and thereby crept up. Other insects, which were 

 injured only upon one side, directed their motions towards the un- 

 wouncled side. Thus an Orgt/ia pudibunda, O., of which the left an- 

 tenna was cut off, kept running in a circle towards the right side, and 

 continued this motion even when it had lost the entire left side of its 

 head ; when, however, the whole head was removed, the creature made 

 violent exertions, running in circles, sometimes on one side, sometimes 

 on the other. The same moth lived three days without its head, and 

 continued to move its wings violently until its death. A different 

 result was however produced when Treviranus removed the antenna of 

 a wasp, for it moved indifferently on both sides. JEschnaforcipata 



* Das Organische Leben, vol. ii. part i. p. 192. 



