388 
correspond to the difference between “antipathy” and “sympathy.” 
The author defines, however, the “antibionts” to be those beings which 
live in a constant struggle with each other, while the “symbionts” live 
in peace and do not cause any injury to each other. Whether these 
“symbionts” are of any mutual benefit is another question. This con¬ 
ception of symbiosis was given by Tubeuf in 1888, who called it “harm¬ 
less symbiose.” 
It is a marked characteristic of the antibionts that their action very 
soon ends the struggle, and their appearance is, therefore, rather lim¬ 
ited. The symbionts, on the other hand, may be observed as constant 
companions for many years. Antibiosis and symbiosis may, when con¬ 
sidered in this way, represent an acute and chronic parasitism. 
The chapter dealing with the appearance of the “root symbiosis” 
comprises the “algal symbiosis,” as we know it from the lichens 
and Hepaticm, and the “fungal symbiosis,” which causes the develop¬ 
ment of root tubercles and similar hypertrophy of roots or organs 
which have the same function as the proper roots, such as fronds with 
rhizoids like those of Hepaticm, etc. It seems as if Dalechamp (1587) 
was the first to describe and figure the root tubercles of the Leguminosse, 
while Malpighi (1079) also described them, and considered them as galls, 
caused by insects. Concerning the morphological identity of these 
tubercles, the Danish botanist Didrichsen (1867) explained them as being 
lateral roots. The anatomical structure was given by Van Tieghem 
(1888), who showed that they differ from normal roots by having several 
central cylinders within a common bark. Their first development is, 
however, to be traced, as in normal roots, from the pericycle of the mother 
root. But besides the Leguminos®, several other plants are mentioned 
as having similar tubercles, both trees and herbs, from the cycads and 
conifers to the annual Junci and Gyperus flavescens. The identification 
of most of the fungi which cause these various hypertrophies, is a very 
difficult task if indeed a possible one. Only a very few are known 
thoroughly, such as Frankia , Rhizobium , etc. 
Frank was one of the earliest writers in the field and has written 
much. He appears to have been the first to demonstrate one phase of 
the question as to the biological importance of the fungal symbio¬ 
sis. This author claims that certain trees, especially all the Cupuli- 
ferse, are unable to take nourishment from the soil by themselves, but 
that they become nourished by means of the fungous mycelia which 
surround their entire root system and nurse them from their earliest 
stage until their death. 
Gibelli, on the other hand, considers this symbiosis as a mere ques¬ 
tion of tolerance on the part of the root, and if we consider the entire 
literature upon this subject, it seems as if the majority of authors 
agree with Gibelli, that the fungus is tolerated by the root only because 
it does not cause it any injury. —Theo. Holm. 
