238 MANUAL OF PHYSIOLOGY. 



These corpuscles and their haemoglobin are manufactured by 

 isolated protoplasmic elements in the connective tissue, and 

 subsequently added to the general mass of blood by the growth 

 of the network bringing it into continuity with the neighboring 

 vessels. 



In the adult the formation of red blood corpuscles is of course 

 much less active, but certainly never ceases to take place in 

 health, for the corpuscles must be renewed as they become worn 

 out, and incapable of performing their function. This reproduc- 

 tion can go on with considerable rapidity, as we see after severe 

 haemorrhage, when the normal richness in haemoglobin and cor- 

 puscles is soon arrived at. Their formation is, however, probably 

 confined to a few special organs spleen, liver, red medulla of 

 bones where transitional forms are found in such numbers as to 

 point to the probability of the red corpuscles being the offspring 

 of the colorless cells, whose protoplasm either manufactures anew 

 or collects the necessary haemoglobin, and then loses its nucleus 

 and ordinary cellular characters. 



We can only guess at the fate of the disks, but there are many 

 things which point to the spleen as the organ in which they are 

 destroyed. In the spleen an enormous number of protoplasmic 

 elements are produced, and the blood comes into relationship with 

 the nascent cells in a way unknown in any other part of the body. 

 Further, various unusual elements, some like altered red cor- 

 puscles, others like white cells enveloping haemoglobin, are found 

 in this organ. 



The blood corpuscles, on coming to the spleen, are possibly sub- 

 mitted to a kind of preliminary test of general fitness, some 

 elements of the spleen pulp having the faculty of examining 

 their condition and deciding upon their fate. Many, no doubt, 

 pass the trial without any change, being found in good working 

 order. Others that are found totally unfit are broken up, and 

 their effete hicmoglobiu carried to the liver to be eliminated as 

 bile pigment. Some possibly undergo a form of repair, a white 

 cell taking charge of a weakly disk renews its stroma, adds to its 

 hemoglobin, and carries it through the final proof in the liver, 

 where it is chemically refreshed before going to the lungs for the 

 load of oxygen which it has to carry to the systemic capillaries. 



