1913] LIVINGSTON—T EMPERATURE COEFFICIENTS 353 
sure that each of its component terms involves at least a quality, 
intensity, and duration of some environmental factor. It is thus 
seen that what is most needed for etiological studies of the geo- 
graphic distribution of organisms, as well as for all other studies 
which deal with the conditioning or causation of life processes, is 
comparative measurements of these processes, or of groups of them, 
and corresponding measurements of the conditioning environ- 
mental factors. To accomplish such measurements and thus to 
institute the requisite comparisons is now practically impossible 
in most cases; methods need first to be devised and then to be 
applied, and the world does not yet offer satisfactory facilities for 
either. Measurements which can be carried out in present-day 
laboratories, while applicable in some cases, especially with forms 
not influenced by light, are quite inadequate even for making a 
rational beginning in the quantitative study of environments in 
general. In planning a campaign for this sort of study it is obvious 
that the effects produced by any environmental factor cannot be 
adequately studied unless that factor, as well as all the other 
effective ones, is under control by the experimenter. A laboratory 
where such experimentation as is here indicated may be carried out 
is now feasible, with recent advances made in the physical sciences 
and in physiology, and the scientific and practical importance of the 
results to be obtained, especially from the standpoint of agriculture 
and forestry, may perhaps soon warrant the provision of the needed 
facilities, somewhere in the world.4 Until such facilities may have 
become available, it will be profitable, however, to prepare the way 
for them by carrying out such quantitative or semi-quantitative 
comparisons between vital activities and environmental conditions 
as are at present possible. 
The present paper involves some of the results of an attempt 
to find a rational method for interpreting climatic temperature data 
for phytogeographic purposes. This sort of study is somewhat 
simplified, in the case of plants, by the fact that the temperature of 
4This need was strongly emphasized over two decades ago by ABBE, who also 
quotes DECANDOLLE to the same effect. See ABBE, C., First report on the relations 
between climates and crops. U.S. Dept. Agric., Weather Bureau, Bull. 36. p. 23, 
19905. 
