Neglected Areas of Nutrition Research 175 



In gerontology this analogous thinking in relation to 

 nutrition may indicate that much can he learned hy use of 

 single celled organisms or very com})lex insects hut that 

 generalizations nuist have some anchorage in experiments 

 with man himself. 



Bacteriologists appreciate that cultures grow old hut 

 limited studies such as those of Otto Rahn (1951) indicate 

 that the process is fully as comphcated and confusing as 

 appears the ageing of higher vertebrates. The use of insects 

 seems to have promise not only because of the vast numbers 

 with which one can work cheaply but also many species pass 

 through their life cycle during brief periods of days or weeks. 

 In his discussion of longevity in the animal kingdom, 

 Metchnikoff (1908) noted: "Between these extremes of long 

 and short life, there is found amongst insects almost every 

 gradation of longevity." 



One need not review the world of fish and lower vertebrates 

 to appreciate the value of studying any of the numerous 

 chordates, some of which have a reputation, true or false, for 

 great longevity. 



One can certainly conclude that no life will be wasted if 

 devoted to the study of ageing material of any form whether 

 it be the seeds of plants or man himself. 



To the student of ageing moulds or rotifers, the specialist 

 devoting his life to the study of man himself may quote 

 Goethe with genuine truth, "Wir sehen uns wieder, weit, gar 

 weit von hier" — gerontologists wdll ultimately meet upon 

 common grounds. 



For the remainder of this discussion it may be well to draw 

 upon our own experiences of twenty-seven years in order to 

 note the fields that might have been cultivated profitably 

 and that were neglected. For a substantial fraction of this 

 period our laboratory used three widely different classes of 

 animals for research upon growth and ageing. These included 

 several insect species but most of the research was done upon 

 the small cockroach, Blatella germanica. For fifteen years, 

 studies were in progress at different times upon species of 



