PERIODICITY IN HUMAN BEINGS AND MICE 853 



decision as to the "right dose." Accordingly, data on synchronized 

 periodicities at various physiologic levels of organization serve two 

 purposes. First, they constitute maps "in time" depicting significant 

 changes in physiologic state. Second, they demonstrate how, in 

 standardized mice, one may obtain certain desired physiologic states 

 at a convenient clock hour, by the manipulation of an easily controlled 

 environmental factor. 



In turning to the problem of effects upon phase of 24-hr rhythms in 

 human beings, the "controversial" state of our knowledge has recently 

 been discussed by Pierach (1955) and earher by Vering ( 1 950 ) . With 

 our results, we shall illustrate merely the feasibility of shifting the 

 phase of certain rhythms in man by a shift in daily routine (including 

 the lighting schedule). 



The timing of eosinophil rhythm, in groups of human males or 

 females, is a function of daily routine (Halberg, Engel, Treloar, and 

 Gully, 1953; cf. also R. B. Howard, 1952; Levy and Conge, 1953). 

 Figure 26e,f exhibits the curves for blood eosinophils and rectal 

 temperature of two individuals living on a schedule providing for 

 activity by day and sleep by night. It must be noted that sleep indicates 

 the usual times of rest; on the day of study, however, the subjects 

 were given their isocaloric meals at equidistant intervals (arrows). 



The curves in Fig. 26e,f are shown for comparison with ( 1 ) those 

 of a subject on a prolonged shifted routine (Fig. 26a) and (2) those 

 of another subject who had two daily periods of sleep for many years, 

 including weekends and holidays. In the latter case (Fig. 26c) there 

 is no significant evidence for a 12-hr rhythm; only once during 24 hr 

 does the eosinophil count overshoot markedly its series mean (100 

 on the ordinate). Superficially, the temperature rhythm in Fig. 26c 

 reveals two peaks, but again, one of these barely exceeds the series 

 mean. 



These results on a schedule interrupted twice a day, consistently 

 for several years, support the inference that the 24-hr eosinophil 

 rhythm of man is not easily made into a 12 hourly rhythm (Halberg, 

 Halberg, and Gully, 1953). The same inference gains support from 

 data obtained during the 12 hourly application of R.E.S.T. for about 

 2 weeks (Fleeson et al, 1957). It is pertinent, however, that in the 

 monkey, O. P. Shcherbakova reportedly (Bykow, 1953) succeeded in 



