THE SCIENCE AND ART OF PROTEAL THERAPY 153 



to be fairly established that the lymphocyte population of the 

 child's blood, and in particular the large monocyte population, 

 decreases with advancing age. This would seem to suggest 

 (holding still to the Proteomorphic interpretation) that the adult 

 organism is in general called upon to deal less comprehensively 

 with the full-sized foreign protein molecule than is the organism 

 of the child. A plausible explanation of this, as already sug- 

 gested, may be found in the obvious needs of the growing organ- 

 ism, where nitrogenous tissue is being built up day by day; as 

 contrasted with the adult organism, where the nitrogenous tissues 

 are only holding their own, or are actually degenerating. 



Incidentally, it may be supposed that the normally large equip- 

 ment of mononuclear cells in the blood of the child and adolescent 

 may account in some measure for the relative immunity to the 

 growth of malignant neoplasms in early life. Contrariwise, the 

 susceptibility of old age to the growth of such neoplasms may 

 be associated with the decreased numbers, and, presumably, de- 

 creased functional activities of the mononuclear leucocytes chiefly 

 concerned in handling unbroken proteins in general and .lawless 

 neoplastic cells in particular. 



FURTHER HINTS AS TO DIFFERENTIAL FUNCTIONS 



Such a suggestion is obviously consonant with the interpreta- 

 tion of the role of the lymphocyte and the large mononuclears 

 put forward in connection with the Proteomorphic theory, and 

 constantly reiterated in the present volume. It must be freely 

 admitted, however, that our knowledge of the subject is at best 

 fragmentary, and that a great deal more work must be done 

 before we can hope for definite answers to many questions that 

 obtrude themselves whenever one considers a blood smear with 

 philosophical that is to say, with childlike inquisitiveness. 



As provisional deductions from my own personal studies, I 

 have suggested the possibility that one chief role of the poly- 

 nuclear leucocytes may have to do with the metabolism of fats. 

 Observation has taught me to expect to find a relative and abso- 

 lute leucopcenia in examining the blood of obese patients of the 

 anaemic type. It has just been remarked that bacteria are sur- 

 rounded by a lipoid covering and have a body structure that 

 incorporates lipoids. It is familiarly known also that the poly- 

 nuclear has to do with the fight against bacteria that being a 

 classical observation of Metchnikoff that has hitherto stood al- 

 most alone as an interpretation of specific functions of a par- 

 ticular type of leucocyte. It is not improbable that lipoids also 

 enter into the constitution of the cell membrane of the cells of 

 the normal organism, and of such modifications of these cells 



