472 SECRETION". 



Summary of the Functions of the Liver. The liver seems to possess more varied 

 functions than any other glandular organ in the body. Under the head of digestion, we 

 have described the function of the bile in the small intestine, and have shown that, 

 although it is difficult to define precisely the action of this fluid, it undoubtedly assists in 

 the digestive process and its function is essential to life. Under the bead of excretion, 

 we have shown that the bile discharges an excrementitious substance, cholesterine, into 

 the small intestine, which, in its passage down the alimentary canal, is changed into ster- 

 corine and in this form is discharged in the fa3ces. When, from any cause, there is a 

 serious interference with the formation of bile, cholesterine has a tendency to accumu- 

 late in the blood, producing a condition called cholestersemia, which is recognizable by 

 certain toxic phenomena. It has also been shown that cholestera3mia may be artificially 

 produced in animals by the injection of cholesterine properly prepared into the circula- 

 tory system. We have just studied the function of the liver as a sugar-producing organ. 

 In this it acts as a ductless gland, producing a substance, by a process analogous to that 

 of secretion, which is not discharged by its excretory duct but is carried away by the 

 blood in the course of the circulation. 



With regard to other functions which have been attributed to the liver, there is little 

 to say in the present state of our knowledge. Bernard held the opinion that the liver 

 was largely concerned in the formation of fat out of the saccharine and amylaceous ele- 

 ments of food ; but the examinations of the matters contained in the blood coming from 

 the liver, which were supposed by Bernard to be fatty, have not been sufficiently minute 

 and accurate to justify any positive conclusions with regard to their character or com- 

 position. While there can be no doubt concerning the actual production of fat in the 

 body independently of the fat taken as food, there is not sufficient ground for regard- 

 ing the liver as an organ specially concerned in its production. The observations of 

 Lehmann with regard to certain changes which he supposed to occur in the nitrogenized 

 elements of the blood in passing through the liver are not sufficiently clear and definite 

 to warrant any positive conclusions. The same remark applies to observations which 

 seem to show that the liver is concerned in the production of the white and red corpus- 

 cles of the blood. 



CHAPTER XIV. 



THE DUCTLESS GLANDS 



Probable office of the ductless glands Anatomy of the spleen Fibrous structure of the spleen (trabeculae) Malpi- 

 ghian bodies Spleen-pulp Vessels and nerves of the spleen Some points in the chemical constitution of the 

 Bpleen State of our knowledge concerning the functions of the spleen Variations in the volume of the spleen 

 Extirpation of the spleen Anatomy of the suprarenal capsules Cortical substance Medullary substance 

 Vessels and nerves Chemical reactions of the suprarenal capsules State of our knowledge concerning 

 the functions of the suprarenal capsules Extirpation of the suprarenal capsules Addison's disease Anatomy 

 of the thyroid gland State of our knowledge concerning the functions of the thyroid gland Anatomy of the 

 thymus Pituitary body and pineal gland. 



CEETAIN organs in the body, with a structure resembling, in some regards, the true 

 glands, but without excretory ducts, have long been the subject of physiological specula- 

 tion; and the most extravagant notions concerning their functions have prevailed in the 

 early history of the science. The discovery of those functions of the liver which consist 

 in modifications in the composition of the blood passing through its substance dimly fore- 

 shadowed the probable office of the ductless glands ; for, as far as the production of sugar 

 is concerned, the liver belongs to this class. Indeed, the supposition that the ductless 

 glands effect some change in the blood is now regarded by physiologists as the most 



