22 SCIENCE PROGRESS 



cells grow upon a medium of sugar and nitrogenous matter, 

 so do the lymph-cells develop upon the sugar and peptone 

 provided by the intestine. 



"Food that has been broken down and placed in a fit state 

 by digestion for absorption is at once dealt with at the seat 

 of absorption and rebuilt into an elaborated form. Dextrose 

 and peptone are alike recognisable at the seat of absorption 

 but both thereafter disappear. At the same time and at the 

 same spot, there is an active bioplasmic growth taking place 

 and bioplasm is known to feed upon dextrose and upon peptone. 

 The lymphocytes which constitute the growing material can 

 be followed from the villi into the absorbent vessels and 

 thence through the thoracic duct into the vascular system." ' 

 Once in the blood, the lymphocytes are broken down into in- 

 diffusible products which become available for the nutrition of 

 the tissues generally. 



However startling and at variance with the trend of modern 

 physiological thought it may be, a theory propounded by so 

 acute a thinker must not be dismissed without examination. 

 Increase of lymphocytes in the blood, as a result of food 

 digestion, is a phenomenon long known and well established. 

 It is quantitative considerations alone which make Pavy's 

 theory difficult of acceptance. It is not, maybe, altogether 

 unthinkable that cells of the type of white blood corpuscles 

 should increase at the great rate postulated by the theory. 

 In the case of unicellular organisms multiplying by fi oion 

 great rates of increase have been observed when the conditions 

 for growth are favourable. But histologically the lymph-cell 

 does not by any means present in its nucleus the characters 

 which are associated with the process of rapid growth ; more- 

 over considerations of the quantities involved, even though we 

 can only estimate them approximately, seem to make the theory 

 quite inconsistent with the facts observed in the animal. An 

 adult man in the course of twenty-four hours eats some 600 

 grammes of protein and carbohydrate taken together. An 

 animal cell contains not less than 75 per cent, of water, so 

 that the actual mass of lymphocytic protoplasm that would 

 be formed from the day's dietary on Pavy's view would weigh 

 perhaps z\ kilogrammes. Now a calculation indicates that the 

 total mass of white cells in the blood under average conditions 



1 See the Lancet, 1908, II. 1584. 



