FACTORS ALTERING CONCENTRATION OF BLOOD LIPIDS 399 



than was that of adults. Ward, 253 Parhon and Parhon, 254 and Kaiser and 

 Gray 239 reported that cholesterol increases with age, although Blix 255 

 does not subscribe to this hypothesis. In any event, the level of blood 

 cholesterol appears to have become stabilized by the advent of puberty. 

 In fact, the work of Hodges, Sperry, and Andersen 256 has failed to demon- 

 strate any significant differences in the cholesterol level in the sera of chil- 

 dren, varying in age from two months to thirteen years, from that of adults. 

 According to these workers, the ratio of total to free cholesterol has also 

 become stabilized at as early an age as two months. Sperry 257 stated that 

 the serum cholesterol is maintained in each healthy person at a constant 

 level. 



Another variation between the composition of the blood of the mother 

 and that of the infant is in the relative lack of the cholesterol ester fraction 

 in the latter instance. If delivery occurred without the use of anesthetics, 

 lower values for the cholesterol esters were found in the blood of the infant 

 than following the use of anesthetics. 249 The calf, also, has been shown to 

 have a blood devoid of the esterified cholesterol at birth. 258 



(d) Blood Lipids in the Young and in the Aged. It has been fairly well 

 established that the blood lipid picture remains essentially uniform as life 

 advances, except as it may be influenced by pathological conditions. In 

 order to obtain data on these points, Page and his collaborators 259 made an 

 extensive investigation on a large group of men varying in age from 20 to 

 101 years. The results of these workers are summarized in Table 10. 

 The average figures of Page et a/. 259 for 66 male subjects (a) compare with 

 those of Boyd 260 for eight subjects (b), and of Man and Peters 261 for twelve 

 subjects (c) as follows: total lipids, (a) 735 ± 216, (b) 582; neutral fats, 

 (a) 225 ± 137, (b) 137; phosphatides, (a) 181 ± 71, (b) 185 ± 21, (c) 

 222 ± 29; total cholesterol, (a) 232 ± 62, (b) 177, (c) 207 ± 29; and 

 free cholesterol, (a) 82 ± 17 and (b) 53 ± 8. Thus, there is considerable 

 evidence that advancing age is without effect on the blood lipids levels in 

 human subjects. 



263 K. M. Ward, Arch. Diseases Childhood, 6, 329-342 (1931). 



264 C. J. Parhon and M. Parhon, Compt. rend. soc. biol, 88, 231-233 (1923). 



265 G. Blix, Acta Med. Scand., 64, 142-174, 175-233, 234-259 (1926). 



256 R. G. Hodges, W. M. Sperry, and D. H. Andersen, Am. J. Diseases Children, 65, 

 858-867(1943). 



267 W. M. Sperry, /. Biol. Chem., 117, 391-395 (1937). 



258 R. E. Shope, J. Biol. Chem., 80, 141-148 (1928). 



259 I. H. Page, E. Kirk, W. H. Lewis, Jr., W. R. Thompson, and D. D. Van Slyke, 

 J. Biol. Chem., Ill, 613-639 (1935). 



260 E. M. Boyd, /. Biol. Chem., 110, 61-70 (1935). 



261 E. B. Man and J. P. Peters, J. Biol. Chem., 101, 685-695 (1933). 



