114 



FUNCTION OF THE LIYER. 



when entering into it. It is, therefore, reasonable to believe that the blood-cor- 

 puscles have their origin in the liver. If the main offices of the liver be the 

 elaboration of the albumen, and the formation of the blood-corpuscles, we might infer 

 that it should be larger in warm than in cold-blooded animals, because in the 

 former the blood is more abundant and much more rapidly formed and consumed 

 in supplying the wastes of the tissues than in the latter. 



Another function of the liver is the production of grape sugar. Physiologists of 

 high reputation suppose that this is used in the production of animal temperature. 

 If the supply of grape sugar corresponds to the temperature, the liver should be 

 largest in warm-blooded animals. 



These are the considerations which led me to investigate the relative size of this 

 organ in different animals. But it must be stated, decidedly, that these views have 

 not been sustained by my researches. A reference to the table shows us that the 

 liver is smaller in Birds than in many Fishes, Reptiles, and Mammals, while 

 the former have the highest temperature and the greatest number of blood-cor- 

 puscles. 



Notwithstanding these results we need not abandon the preceding physiological 

 doctrines, as no organ in the bodies of animals is so liable to alterations in its 

 weight, unconnected with its secretory or excretory apparatus, as the liver. 

 Fishes especially contain an extraordinary amount of oil. I have detected the 

 presence of oil under the microscope, in the form of innumerable small globules 

 in the livers of all animals, and even in the livers of cold-blooded animals which 

 had been starved for sixty days, and warm-blooded animals which had been 

 starved to death. In the cold-blooded animals, although every particle of fat had 

 disappeared from their tissues, and the animals had died from starvation, still oil 

 globules were found in considerable numbers in their livers. Again, the structure 

 of the liver in cold-blooded animals, and fishes especially, is much softer and less 

 compact than in the warm-blooded ones. These facts show that the weight of 

 the liver is not a true exponent of that portion of the gland which is devoted to 

 the elaboration and formation of the constituents of the blood. 



The livers of all animals, cold or warm-blooded, always, as far as my observation 

 has extended, yield grape sugar. I have detected its presence by various tests in the 

 livers of numerous Fishes, Batrachians, Ophidians, Chelonians, Birds, and Mammals. 

 I have found it in the livers of cold-blooded animals at all periods of starvation, and 

 even after death from a deprivation of food and drink. In the liver, however, of a 

 dog which was starved to death, I failed to discover any of it. 



These facts show that, during starvation, grape sugar must be formed in the 

 animal economy in part, from the nitrogenized elements. 



One of the most prominent effects of starvation in all animals is the consump- 

 tion of the fatty matters. Fat is found in considerable quantities in the livers of 

 all animals, whether supplied with, or deprived of food and drink ; and a universal 

 accompaniment of this fat is grape sugar, a substance closely allied to it in chemical 

 constitution. A relation, therefore, appears to exist between the consumption of 

 fat in the animal economy and the production of grape sugar; but what this relation 

 is, and whether grape sugar is formed from fat, has never been determined. 



