THE RHYTHMIC UNIVERSE 375 



sun/^ The investigators who discovered these very interesting 

 exceptions claimed or implied that the rhythms in the bean 

 seedlings or insects which they used, depended upon rhythmic 

 changes in the environment which, in some manner, still per- 

 vade all ordinary so-called laboratory contant conditions. 



Dr. Brown's own observations of an interference in the 

 rhythms of oxygen consumption by organisms which correlated 

 with changes in outside barometric pressure constituted for 

 him the recognition that not only geophysical, but even cosmic 

 forces have a governing external influence on the rhythms of 

 terrestrial organisms. He states that it was the rhythm in 

 oxygen consumption of organisms matching changes in baro- 

 metric pressure which led him to consider cosmic radiation as 

 a possible factor in the periodicities. Evidence has now been 

 obtained to show a definite relationship between the metabolism 

 cycles of several organisms and certain fluctuations in cosmic 

 radiation.^* Dr. Brown also showed that fiddler crabs exhibit 

 a measurable response in the state of their pigmentary systems 

 to alterations in the intensity of cosmic ray showers by shield- 

 ing the animals with varying thicknesses of lead sheets.^^ 

 Other possible factors suggested are the differences of potential 

 between the earth and the ionosphere and the various magnetic 

 fields: 



There is good likelihood, judging from the known simultaneous 

 influence of such forces as light, temperature and tactile stimuli, 

 that if these organisms possess the capacity to respond to one type 

 of these relatively low-energy, or diffuse, types of environmental 

 stimuli such as are implied by these results [correlation between 

 oxygen consumption in organisms and the barometric pressure], 



^^ Frank A. Brown, Jr., " The Rhythmic Nature of Animals and Plants," Cycles, 

 XI (1960) . 87; and "An Exogenous Reference-Clock for Persistent Temperature- 

 Independent, Labile, Biological Rhythms." Biol. Bull., CXV (1958), 81-100. 



^* Frank A. Brown, Jr., H. M. Webb and M. F. Bennett, " Comparisons of Some 

 Fluctuations in Cosmic Radiation and in Organismic Activity During 1954-1955 and 

 1956," Am. Jour. Physiol., CXCV (1958), 237-243. 



" Frank A. Brown, Jr., H. M. Webb, M. F. Bennett and M. I. Sandeen, " Evi- 

 dence for an Exogenous Contribution to Persistent Diurnal and Lunar Rhythmicity 

 under So-called Constant Conditions," Biol. Bull., CIX (1955), 238-254 



