676 ANIMAL HEAL 



that when both optic thalami have been removed they become 

 poikilothermal (Krehl, etc.). The greatest mass of evidence points, 

 however, to the corpora striata as structures more intimately con- 

 cerned in temperature regulation than any other. Puncture of the 

 median portion of the corpus striatum in the rabbit by a needle 

 thrust through a trephine hole in the skull is followed in a few 

 hours by a rise of temperature in the rectum (i to 2), and still 

 more in the duodenum, which is normally the hottest part of the 

 body in this animal. The heat-production, the respiratory exchange 

 and the nitrogen excretion are increased. These phenomena may 

 last for several days (Ott, Richet, Aronsohn, and Sachs), and are 

 due to stimulation of the portions of the brain in the immediate 

 neighbourhood of the injury. Electrical stimulation of this region 

 has a similar effect. When the temperature has returned to 

 normal, a fresh puncture may again cause a rise. 



As to the manner in which these centres are excited, there is 

 some evidence that, in addition to any influence exerted on them 

 by afferent nerves, they are capable of being directly affected by 

 the temperature conditions of the blood passing through them, as 

 well as by numerous drugs. Thus it is stated by Barbour and Wing 

 that direct application of cold to the region of the corpus striaturn, 

 especially its caudate nucleus, in rabbits causes a rise in the rectal 

 temperature, associated with shivering and consequent increase of 

 heat-production in the contracting muscles, and with peripheral 

 vaso-constriction and consequent diminution in the heat-loss. 

 The application of warmth has the opposite efiest : the peripheral 

 bloodvessels dilate, the animal becomes quiet, and the rectal tern 

 perature falls. 



Some observers hold that the chief seat of the increased metab- 

 olism in the puncture fever is the skeletal muscles, others the liver. 

 The question turns largely upon the success of the puncture ex- 

 periment after the previous administration of curara on the one 

 hand, and of strychnine on the other. For curara cuts out the 

 motor innervation of the skeletal muscles, and strychnine convul- 

 sions exhaust the store of hepatic glycogen. Certain investigators 

 have found that after an adequate dose of curara no puncture fever 

 can be obtained, and they locate the increased metabolism asso- 

 ciated with the fever in the muscles. Others maintain that even 

 after curara the puncture is followed by fever, but is not followed 

 by fever if strychnine has first been given. They accordingly con- 

 clude that the rapid combustion of the glycogen (or the dextrose 

 derived from it) is the primary factor in the increased metabolism. 

 It may be pointed out, however, that neither experiment is a crucial 

 test. For if strychnine reduces tile liver glycogen, it also reduces 

 the glycogen of the muscles. And if in the puncture fever the liver 

 glycogen is transformed into dextrose more rapidly than usual, the 



