I'h'OLIFl'Jh'ATlOX AM) UEGEN ERATION '111 



Even transplanted bits of uterine tissue are stimulated to j^row Ijy 

 these substances, thus excluding possible nervous control of growth.* 

 Dried placenta fed to mothers also increases the rate of growth of the 

 suckling infant (Hammett).*^ The nature of the growth-stimulating 

 agency in placenta and corpus luteum is unknown but it strongly 

 resists chemical agents. However, it may be pointed out that tethelin, 

 described by Robertson^ as the growth-promoting substance of the 

 hypophysis, is soluble in lipoid solvents. Acromegaly and gigantism, 

 give evidence that even far more than normal growth ma}' be produced, 

 presumably through the agency of an internal secretion of the hypo- 

 phesis, but whether tethelin actually is the substance responsible is 

 at present unknown. This substance is obtained from the anterior 

 lobe, about 10 mg. for each gland, and contains 1.4 per cent, of phos- 

 phorous. It is said to retard growth of animals before adolescence 

 and to increase post-adolescent growth; also it has been reported that 

 wound repair is stimulated by tethelin.* At this time, however, the 

 status of tethelin is not fully determined. The influence of the other 

 ductless glands on growth is discussed further in Chapter xxii. 



The studies by Whipple and his colleagues on the repair of the liver 

 after extensive chloroform necrosis indicate that a mixed diet rich in 

 carbohj'drate is more effective in facilitating this repair than meat or 

 fat, and that thyroid extract does not stimulate repair.^ Also the 

 healing of wounds is more rapid in meat-fed than in fat-fed dogs. 

 (Clark) ^^ Attempts to find specific substances that will cause in- 

 creased rate of wound healing have so far been unsuccessful." Re- 

 generation of blood protein after hemorrhage is said to be most rapid 

 on a protein rich diet.^- When an incomplete protein, ghadin, is the 

 sole protein of the diet the hemoglobin is not regenerated. 



Although proper nutrition is necessary for cell proliferation, yet it 

 does not seem that excessive nourishment can lead to excessive cell 

 multiplication, or by itself cause cell proliferation to take place. 



Oxygen and certain inorganic salts are essential for cell division 

 even in the lowest forms, and among such simple organisms as sea- 

 urchins and certain other marine forms segmentation of the unfertilized 

 ova may be incited bj^ changes in osmotic concentration, leading 

 eventually to formation of perfect larvae (J. Loeb, et. al.).''-^ In lower 

 animals very dilute solutions of alkalies stimulate the rate of cell 

 growth and somewhat higher concentrations cause extremely irregular 

 cell division; in mammals the feeding of alkalies causes great wasting 



"' Frank, Surg. Gyn. Obst., 1917 (25), 329. 



" Jour. Biol. Chem., 1918 (36), 569; Endocrinology, 1919 (3), 307. 



' See Jour. Exp. Med., 1916 (23), 631. 



^ Review by Barney, Jour. Lab. Clin. Med., 1918 (3), 480. 



=> See Arch. Int. Med., 1919 (23), 689. 



'" Bull. Johns Hopkins Hosp., 1919 (30), 117. 



'iSee DuNoiiy, Anaer. Jour. Physiol., 1919 (49), 121. 



'2 Kerr et al, Amer. Jour. Physiol., 1918 (47), 456. 



'^See J. Loeb, Studies in General Physiology, Chicago, 1905. 



