446 Chronicles of Science. [July, 



Physiology. 



The Blood and Work. — According to Hoppe-Seyler, the con- 

 stituents of the tissues are oxidized outside the blood-vessels, and 

 not after they have found their way into the blood, as maintained 

 by Estor and Saintpierre. Hirschman opposes also the view that 

 carbonic acid is formed in the blood at all. He maintains that it 

 is formed in the tissues, and passes thence into the blood. Mr. C. 

 W. Heaton, of Charing Cross Hospital, comes forward in the 

 'Philosophical Magazine' to maintain the view that oxidation 

 takes place in the blood. His opinions will be found in his article 

 on this subject in the present Number. 



'Regulation of the Heat of the Body. — Van der Hoeven was 

 one of the first to point out the inaccuracy of the common division 

 of animals into " warm " and " cold " blooded — the true expression 

 of the difference not being contained in the words. What we call 

 cold-blooded, animals are those animals which have but little inde- 

 pendent temperature, but vary almost equally with the medium 

 which surrounds them. Warm-blooded animals, on the other hand, 

 are such as have the power of both lowering and raising their 

 own temperatures relative to that of the circumambient fluid. 

 MM. Jacobson and Landre, of Utrecht, have recently made some 

 observations on this power of self-regulation. Bergmann and 

 Donders recognized in the skin the moderator of animal heat, and 

 found that in its vaso-motor nerves the self-regulation takes place. 

 In different animals particular parts of the skin are specialized as 

 moderators. In the dog, the paws, nose, and tongue ; in the ape, 

 parts of the face; in cocks and turkeys, the vascular combs and 

 gills, which usually have a low temperature, but under particular 

 circumstances become very warm. The ears of the rabbit are 

 perhaps the most remarkable of any of these organs, since they are 

 provided with means of an alternate contraction and dilatation of the 

 blood-vessels. MM. Jacobson and Landre have experimented suc- 

 cessfully on the rabbit, and have fully shown that the ears have 

 this important function ; and further, that its exercise is entirely 

 dependent on the sympathetic system of nerves. 



The Croonian Lecture for 1867. — Dr. J. B. Sanderson's 

 purpose in the Croonian lecture, delivered before the Koyal Society, 

 " On the Influence exerted by the Movements of Bespiration on the 

 Circulation of the Blood," was to show the incorrectness of the state- 

 ment frequently made, that the frequency of the pulse is lowered 

 and arterial tension diminished during inspiration. He shows, on 

 the contrary, by experiments made upon dogs, that the immediate 

 effect of inspiration as well as of exspiration, in natural breathing, 

 is to increase both the force and frequency of the heart's action ; 

 and even when the trachea was plugged and stopped, the efforts 



