PROGRESS IN ANATOMY ANU PHYSIOLOGY 



poses of the organism, supplemented by a set of ex- 

 cretory organs, through which the waste products 

 the ashes are eliminated from the system. 



But there remain, broadly 

 speaking, two other sets of 

 organs whose size demon- 

 strates their importance in 

 the economy of the organ- 

 ism, yet whose functions are 

 not accounted for in this 

 synopsis. These are those 

 glandlike organs, such as the 

 spleen, which have no duct 

 and produce no visible se- 

 cretions ; and the nervous 

 mechanism, whose central 

 organs are the brain and 

 spinal cord. What offices 

 do these sets of organs per- 

 form in the great labor-specializing aggregation of cells 

 which we call a living organism? 



As regards the ductless glands, the first clew to their 

 function was given when the great Frenchman Claude 

 Bernard (the man of whom his admirers loved to say, 

 " he is not a physiologist merely ; he is physiology it- 

 self ") discovered what is spoken of as the glycogenic 

 function of the liver. The liver itself, indeed, is not a 

 ductless organ, but the quantity of its biliary output 

 seems utterly disproportionate to its enormous size, par- 

 ticularly when it is considered that in the case of the 

 human species the liver contains normally about one- 

 fifth of all the blood in the entire body. Bernard dis- 

 covered that the blood undergoes a change of composi- 



.. 351 



CLACDE UEKXAKD 



