RELATIONS OF CLIMATE AND LIFE 99 



riods. Formerly, this suspension of activity by animal life on account 

 of cold was called hibernation, which means winter rest. The writer has 

 shown (Pierce, W. D., 1916, Joum. Agr. Res., vol. 6, pp. 1183-1191) 

 that this same inactivity may be caused by dryness or heat and possibly 

 by excessive humidity, and that a creature may remain in the same 

 state of inactivity from the heat of summer through the cold of winter 

 and be awakened from it only by the addition of a requisite amount 

 of moisture at eiFective temperatures. We must seek other terms than 

 hibernation, or winter rest, and aestivation, or summer rest. As this 

 rest consists essentially of an almost complete cessation of all bodily 

 functions, and is a state of insensibility, we may very properly designate 

 the so-called hibernation as RHIGANESTHESIA, or insensibility due 

 to cold. This state may be acquired naturally as winter sets in, or may 

 be artificially induced at any time of the year by lowering the tempera- 

 ture. The temperatures inducing RHIGANESTHESIA are grouped 

 into the LOWER ZONE OF INACTIVITY, or the ZONE OP RHIG- 

 ANESTHESIA. 



As the temperatures increase, a creature in the state of rest or 

 rhiganesthesia, commences to show slow movements of the body fluids, 

 and slight jerky motions, which increase with increase of temperature. 

 This awakening or anastasis, when caused by tetnperature change, is a 

 THERMANASTASIS. 



The approximate point at any given humidity at which thermanastasis 

 begins is the ZERO OF EFFECTIVE TEMPERATURE. It must be 

 firmly fixed in your minds that there is not a single zero of effective 

 temperature, as so often claimed, but a different one for every degree or 

 portion of a degree of relative humidity. In other words, at one humidity 

 the awakening may occur at one temperature, and under other conditions 

 of humidity the temperature may be considerably higher or lower. These 

 points can be connected by a curve which represents the lower limit of 

 the ZONE OF ACTIVITY, or the THERMOPRACTIC ZONE, mean- 

 ing a zone of efi'ective temperatures. 



Many authors have manifested considerable confusion in their writ- 

 ings and have even claimed that other authors were incorrect because a 

 certain developmental period or reaction was accomplished in their ex- 

 periments at a given temperature in a certain period of time while the 

 other investigators obtained totally different results. A man working 

 in a moist coastal section could not justly compare his results with those 

 of a man working in a drier section unless the conditions of humidity were 

 recorded also. For this reason, the writer has maintained that labora- 

 tories attempting to correlate temperature with life history, must at least 

 be equipped with maximum and minimum thermometers and a sling 

 psychrometer for determining humidity, and that accurate results are 



