80 APPLIED PHYSIOLOGY 



amounts in the rare and interesting disease methaemo- 

 globinuria. It probably owes its production to the 

 action of the acids of the urine on haemoglobin. It is 

 also produced from haemoglobin in poisoning with 

 chlorate of potash and antifebrin. 



The duration of life of a red corpuscle is a point 

 upon which, unfortunately, we have no information, for 

 one cannot earmark one and trace its development, as 

 naturalists have done for fish, by passing a dated metal 

 plate through a fin. Transfusion experiments indicate 

 though rather doubtfully that the average length of 

 life is about three to four weeks. At all events, although 

 all the corpuscles in any given drop of blood appear 

 exactly alike, they must really be of different ages, and 

 presumably therefore of different degrees of vitality. In 

 accordance with this, one finds a great variation in the 

 resistance offered by different corpuscles to disintegrating 

 agencies, such as may be active in disease. 



The ultimate fate of the red corpuscle is to be broken 

 down in the portal system, and got rid of in the form of 

 bile.* The spleen also seems to take a share in re- 

 moving the corpuscular debris from the blood (vide infra). 

 Whether a corpuscle is only destroyed when it is old 

 and effete, or whether some ' massacre of the innocents ' 

 also goes on, it is impossible to say with any assurance. 



It would seem that the liver, spleen, and marrow 

 can retain the broken-down pigments of about 87 c.c. 

 (3 ounces) of blood, but not more ; and should the de- 

 struction of blood in the portal area be greatly increased, 



* See Hunter, ' Pernicious Anaemia,' and Heinz, Beitr. a. Path. 

 Anat. u. Allgem. Path., 1901, xxix. 299. 



