OF TREE BRANCHES AT FREEZING TEMPERATURES 31 
HIsTORICAL 
A brief summary of the contents of papers relating to the sub- 
ject of this paper is given below. 
It isa noteworthy fact that comparatively little is to be found in 
the literature on the thermometric movement of branches of trees. 
Moreover, references in recent botanical papers to the few con- 
tributions on the subject are rare indeed; it is for this reason that 
the phenomenon is not well known among botanists. The writer 
was at first unable to find any published account of the gross 
thermometric movements to be described, but after the observa- 
tions had been partly completed, his attention was called by Dr. 
J. T. Grossenbacher, of the Bureau of Plant Industry, Washington, 
D. C., to two papers on the subject, one by Robert Caspary, and 
the other by N. Geleznow, which were published in 1866 and 1872 
respectively. Dr. Grossenbacher, having observed an abstract 
of the writer’s observations,* published an article chiefly devoted 
to a discussion of these two early researches.t To quote from a 
footnote in his paper: “This review of the literature of branch 
movements and observations grew out of a study of crown-rot of 
fruit trees and is published separately because it is only indirectly 
related to the main theme.’ Owing to the publication of a 
review of these papers, they are referred to more briefly in the 
present paper than otherwise would have been the case. 
Mr. John Rogers, at Kent, England, was apparently the first 
- to observe the movement of large branches of trees in cold weather. 
His first observations were made as early as 1838, and a short 
note on the observations was published a few years later.{ 
In 1865, Professor Caspary, of K6nigsberg, made a series of 
measurements of the phenomenon observed by Rogers, on a 
number of species of trees in the K6nigsberg botanical gardens. 
The observations were published under the title, ‘‘Uber die 
verainderungen der Richtung der Aste holziger Gewachse bewirkt 
durch niedrige Warmegrade.’’§ Caspary found three ‘types oa 
* Branch movements of certain trees in freezing temperatures. netiere 13 
86-87. I91I3- 
+ Branch movements induced by changes of temperature. Science II. 38: 
201-205. I0913. 
Trans. Hort. Soc. London II. 2: 230. 1842. 
§ Internat. Hort. Exhib. Bot. Congress 98-117. 1866. 
