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 



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. 



