Royal Society. 511 



plied, as elsewhere, by the artery, and that their efferent vessels are 

 radicles of the vena portae within the organ, and join its branches as 

 they are dividing to form the plexus surrounding the tubes ; thus 

 corresponding with the hepatic origin of the great vena portae. In 

 other words, the vena portas is an appendage to the efferent vessels 

 of the Malpighian bodies, and aids them in supplying blood to the 

 plexus of the tubes. Thus in this variety of the kidney, as in the 

 liver, there is an internal as well as an external origin of the portal 

 system ; while in the kidney of the higher animals, this system has only 

 an internal or renal origin, viz. that from the Malpighian bodies. 



A detail of the results of injection by the arteries, veins and ducts 

 is then given, and they are shown to accord with the preceding de- 

 scription. Many varieties in the Malpighian bodies in different ani- 

 mals are also pointed out, especially as regards their size. 



The author then proceeds to found on his previous observations, 

 and on other grounds, a theory of a double function of the kidney. 

 He conceives that the aqueous portion of the secretion is furnished 

 by the Malpighian bodies, and its characteristic proximate princi- 

 ples by the walls of the tubes. After giving in detail his reasons 

 for entertaining this view, he concludes by referring to the striking 

 analogy between the liver and kidney both in structure and func- 

 tion, and by expressing his belief, first, that diuretic medicines act 

 specially on the Malpighian bodies, and that many substances, espe- 

 cially salts, which when taken into the system have a tendency to 

 pass off by the kidneys with rapidity, in reality escape through the 

 Malpighian bodies ; secondly, that certain morbid products occa- 

 sionally found in the urine, such as sugar, albumen, and the red par- 

 ticles of the blood, also, in all probability, pass off through this bare 

 system of capillaries. 



This paper is illustrated by numerous drawings from injected and 

 recent specimens. 



March 3. — A paper was read, entitled, " On the Diurnal Tempe- 

 rature of the Earth's Surface, and the discussion of a simple For- 

 mula for ascertaining the same." By S. M. Drach, Esq. Commu- 

 nicated by John Lee, Esq., LL.D., F.R.S. 



The author observes, in his introductory remarks, that during a 

 period of twenty-four hours the quantity of calorific rays emitted from 

 the sun, and falling on the exposed atmosphere of the earth, is pro- 

 portional to one day's area as swept by the radius vector divided by 

 the square of that radius ; or Ls proportional to the true angular mo- 

 tion for that day ; which is equivalent to substituting the declinations 

 resulting from the true longitudes for those deduced from the mean 

 ones at mean noons. On the arrival of the rays at the superior limit 

 of our atmosphere, they undergo refraction, absorption, and difficulty 

 of conduction ; and when arrived at the surface of the earth, they 

 sutier radiation and reflection ; the absorption alone, at a vertical di- 

 stance, amounting to upwards of one-i'ourth. The maximum sensible 

 heat, he proceeds to observe;, appears to follow the sun in its diurnal 

 revolutioi;, being similar, in this respect, to the point of maximum 

 tidal height of the oceau ; hence he appliea the term thermal esta- 



