INFLUENCE OF INANITION. 351 



may exert some influence on these corporeal conditions, it must 

 be very indirect in its nature. 



Marchand was induced to believe from his earlier experiments 

 on frogs, that the difference between the diurnal and nocturnal 

 excretion of carbonic acid was very considerable ; he found, how- 

 ever, from his subsequent observations, that the apparent excess 

 of the diurnal over the nocturnal excretion in his former experi- 

 ments was entirely owing to the circumstance that the frogs were 

 employed for the day-experiments immediately after their capture, 

 while the same exhausted animals were again used for the night- 

 observations. Marchand has, therefore, also been led to the 

 conclusion, that the influences of day and night are very incon- 

 siderable, and that, the slight diminution in the excretion of car- 

 bonic acid during the night can only be referred to the more quiet 

 condition of the animal during that time. 



It might, a priori, be concluded that those internal conditions 

 of the animal organism which are closely connected with nutrition, 

 and which, therefore, have a direct bearing upon the constitution of 

 the blood, must exert the most marked influence on the respira- 

 tion ; and such indeed has been proved to be the case by various 

 experiments on the respiratory functions during digestion, as well 

 as during fasting, and after the use of certain articles of food and 

 drink. 



On passing to the consideration of the condition of the respira- 

 tion during complete abstinence from food, we find that all observers 

 coincide in this point, that fasting essentially influences all the 

 excretions, including that of the lungs. Letellier found that 1000 

 grammes' weight of turtle-doves, which exhaled 5*687 grammes of 

 carbonic acid in an hour when they were fed upon grain, excreted 

 only 4' 120 grammes of this gas within the same time after having 

 fasted seven days. Boussingault* made a similar observation on 

 the same animals, and found that 1000 grammes' weight of them, 

 which hourly exhaled 4' 169 grammes of carbonic acid when fed 

 with millet, yielded only 2*050 grammes after a seven days' fast. 

 Marchand has very carefully investigated the diminution of the 

 respiratory products and their relation to the absorbed oxygen in 

 frogs while fasting. His numerous series of experiments, some of 

 which embrace long intervals of time, appear clearly to show that 

 these animals gradually exhale less carbonic acid, and absorb less 

 oxygen; it is, however, worthy of notice that the ratio of the 

 absorbed oxygen to the exhaled carbonic acid, always rises until it 

 * Ann. de Chim. et de Phys. 3 Se'r. T. 11, p. 433. 



