32 Hoppe-Seyler on the Diffusion of Cane-sugar fyc. in Water. 



plete cooling of the body. The equality in the quantity of urea 

 separated on the day of rest and on the working-day confirms 

 the observation made by Voit in the case of the dog, that in- 

 crease in muscular work produces no increase in the decomposi- 

 tion of albumen. 



These experiments acquire confirmation from some which 

 Henneberg made in 1865 with two oxen in the respiration-ap- 

 paratus at Weende. He only observed during twelve hours of 

 daytime, and found that the quantity of oxygen taken in at day- 

 time is not sufficient to explain the great quantity of excreted 

 carbonic acid. In twenty-two experiments with different kinds 

 of food, he obtained for 100 parts of inspired oxygen 131, 173, 

 145, 193, 163, 132, 259, 222 parts of oxygen in the exhaled 

 carbonic acid. The circumstance that the apparatus at Weende 

 can only be used in summer, and that he was prevented from 

 prosecuting the experiments in the summer of 1866, were the 

 reasons that Henneberg was hindered in experimentally demon- 

 strating the cause of its abnormality. 



In proving the necessity of a store of oxygen in the body for 

 the exertion of mechanical force, the authors made two experi- 

 ments with patients suffering from diabetes mellitus and leukaemia 

 lienalis. Persons suffering from these diseases have always 

 good appetite, but even with the richest and most nourishing- 

 food have not the smallest feeling of power, and are not refreshed 

 by sleep. Experiment showed that in the case of these there is 

 by no means such a difference of exhalation of carbonic acid and 

 absorption of oxygen between clay and night as in the case 

 of healthy subjects. Those suffering from leuksemia absorb less 

 oxygen at night than at day. 



The authors think, and undoubtedly with reason, that the 

 study of the products of respiration of man and animals will 

 contribute to an accurate knowledge of the process of nutrition, 

 both in the healthy and in the sick subject. 



Hoppe-Seyler* has made some experiments on the diffusion 

 of cane-sugar, grape-sugar, albumen, and gum in water. A 

 solution of these bodies was placed in a glass vessel with plane 

 parallel sides in such a manner under water as to avoid any mix- 

 ing. The progressive diffusion was determined in different layers 

 by means of a polariscope. Complete experiments were in fact 

 only made with cane- and grape-sugar; an extremely slow dif- 

 fusion was observed in the case of gum and albumen. The 

 author sums up his principal results as follows : — 



(1) The velocity of the motion of diffusion which a body ex- 

 hibits in a liquid is, apart from its chemical affinity and the co- 

 * Zeitschrift fur Chemie, January 1867. 



