THE RHYTHMIC NATURE OF LIFE 297 



The common earthworm behaved differently. Ralph, working in my 

 laboratory, found them to have both daily and lunar rhythms of Oa-con- 

 sumption, but the cycles were upside down relative to those of other ani- 

 mals and plants. In other words, their Oo-consumption was higher when 

 barometric pressure was rising and lower when it was jailing. 



Carrots also possessed daily and lunar rhythms of 02-consumption, but 

 they were different even in form from the others. The carrot had a lowered 

 rate of Oo-consumption whenever the barometric pressure was changing 

 in either direction and the amount of reduction reflected directly the rate 

 of pressure change. The carrot, in other words, tended to show its low rate 

 of metabolism not only when the potato or fiddler crab did, but also showed 

 a low rate when the potato or fiddler crab showed a high rate. 



These extensive studies of Oo-consumption clearly indicated that, even 

 in a photographic darkroom, at unvarying temperature and humidity, the 

 animals and plants were able to receive and show a metabolic response to 

 some rhythmically varying external factor. The factor was obviously some 

 general cosmic one, inasmuch as it could be readily shown that, when 

 02-consumption increased in one living thing in one darkroom in our 

 laboratory, there was, simultaneously, far more commonly than pure 

 probabiHty would dictate, an increase in another species in another dark- 

 room in another part of the building, if the species was one exhibiting the 

 same sign of correlation with barometric pressure. Whatever the forces 

 operating, the walls and ceilings of a reinforced concrete and brick build- 

 ing were no barrier to them. 



Although it seems quite clear that fluctuations in some external factor 

 induce changes in oxidative metabolism of organisms, the sign of the re- 

 sponse of the organism to this factor may differ not only with species, but 

 even in the same species from time to time. Not only did the earthworm 

 show in 1954 an essentially inverted relationship relative to most other 

 organisms investigated concurrently ; but the mean daily cycles of the 

 potato, Fiicus, and two species of fiddler crabs, obtained during spring and 

 summer months of 1955, were nearly complete inversions of those ob- 

 tained in 1954. It can be shown that the signs also change from time to 

 time over shorter periods and that the mean daily cycle form reflects 

 simply the predominant sign for the period of the analysis. The cause of 

 the sign changes is completely obscure at present. 



Among the possible external rhythmic factors of which one thinks at 

 once are barometric pressure changes. The normal range of variation in 

 barometric pressure is more than an inch of mercury. Those who have 

 lifted a small bottle of mercury can well appreciate how heavily a 1 -inch- 

 thick blanket could lie upon one. On the other hand, the air above us serves 

 as an indispensable absorber of much of the continuous rain of cosmic 



