568 Chronicles of Science. [Oct., 



leaving the nozzle causes the powders to become electrified, and 

 the sulphur being negatively electric is attracted by tlie curved 

 figures positively electric on the cake, while the red-lead follows 

 the opposite course. M. Meunier has tried thus to separate sulphur- 

 bearing trachite into its mineral constituents, and succeeded per- 

 fectly in getting the sulphide and feldspar from each other : he 

 states that he has succeeded equally well with rocks made up of 

 two difierent silicates. 



12. ZOOLOGY— ANIMAL PHYSIOLOGY AND 

 MOEPHOLOGY. 



Physiology. 



The Temperature of the Human Bod]/. — Mr. Alfred H. Garrod, 

 of St. John's College, Cambridge, has made (and conununicated 

 to the Eoyal Society) a series of observations on a human 

 "subject, aged 22, male, thin," whom we take to be himself, by 

 means of very delicate thermometers and the sphygmograph, 

 which he considers show that the minor fluctuations in the tem- 

 perature of the human body, not including those arising from the 

 movements of muscles, mainly result from alterations in the amount 

 of blood exposed at its surface to the influence of external absorb- 

 ing and conducting media. It has long been known that cold 

 contracts and heat dilates the small arteries of the skin, respectively 

 raising and lowering the arterial tension, and thus modifying the 

 amount of blood in the cutaneous capillaries. But modifications 

 in the supply of blood to the skin must alter the amount of heat 

 difiused by the body to surrouuding substances ; and so we should 

 expect that by increasing the arterial tension, thus lessening the 

 cutaneous circulation, the blood would become hotter from there 

 being less facihty for the difiusion of its heat ; and that by lowering 

 the tension, thus increasing the cutaneous circulation, the blood 

 would become colder, throughout the body, from increased facility 

 for conduction and radiation. Thus the temperatiu'e and tension 

 rise together on stripping ofi" the clothes m a cold air — the tempera- 

 ture and tension fall by covering even a part of the body when 

 stripped ; simply heating the feet lowers the tension and the tem- 

 perature of the body together. Mr. Garrod gives his observations 

 very carefully, in numerous neatly-constructed tables, and appears 

 to have well established his point. He remarks that the fall in the 

 temperature of the body at night observed by Dr. Ogle, and by 

 Drs. Kinger and Stewart, which is lowest at from 12 to 1 a.m., and 

 rises after that time, is due to the fact that Englishmen go to bed 



