88 



APPLIED PHYSIOLOGY 



It has been calculated that there are about 25,000 

 million leucocytes in the whole blood, which if gathered 

 together would make up a solid organ about as large as 

 the thyroid.* 



At birth the total leucocytes number 17,000 per cubic 

 millimetre, but have fallen by the end of a year to 

 14,000, and by the end of three years have reached 

 the adult standard. The excess in the earlier years is 

 entirely due to an increased number of lymphocytes. 



:20.000 



5.000 

 4,000 

 3,000 

 &000 



FIG. 1. ABSOLUTE NUMBER OF LEUCOCYTES PER CUBIC MILLIMETRE 



AT DIFFERENT AGES. 

 A, Polynuclears ; B, Lymphocytes. 



The relative numbers of the different forms present at 

 different ages will be found in graphic form in Figs. 1 

 and 2. 



A distinct increase in the number of leucocytes can 

 usually be observed a few hours after a meal, which is 

 sometimes due to an increase in the polynuclear cells, 

 and at others to an augmentation of uninuclears. The 



* Muir calculates that all the white cells in the blood put 

 together would not suffice to form more than an ounce of pus. 



