and its Mycorhiza . 351 
endotrophlc. With regard to the ectotrophic mycorhiza, he 
appropriates KamienskFs theory that the Fungus prepares 
food for the host ; and in particular supposes that the Fungus 
assimilates, partly for the benefit of the host, humous com- 
pounds. But the endotrophic Fungus he regards as a living 
organism captured by the host. Fie says 1 , ‘ Denn der Pilz ist 
hier gleichsam in den Wurzelzellen gefangen, wo er als 
sichere Beute zuletzt von der Pflanze aufgezehrt wird. Die 
Erscheinung entspricht, mutatis mutandis, genau dem In- 
sectenfang der sogenannten insectenfressenden Pflanzen, und 
wir konnen daher die endotrophen Mycorhizen als Pilzf alien 
und die betreffenden Pflanzen als pilzverdauende Pflanzen 
bezeichnen.’ He then goes on to say that it is probable 
that the hyphae receive the whole of their nutriment directly 
from the external substratum, not from the host. His theory, 
or rather definite statement, is based upon observations made 
on roots of Orchis . He states that in the cortex the proto- 
plasm of the hyphal clumps is drained out of the hyphae, and 
all the proteids resulting pass into the cells of the host ; and 
that finally the hyphal clump consists solely of the walls 
of the hyphae. His evidence for these statements is that 
with increasing age the hyphal clumps gradually lose their 
power of staining with anilin-blue. Admitting this diminution 
of staining power and that it is due to a disappearance of 
proteid, still Frank fails to exclude the possibility that the 
proteid might be converted into cell-wall or into additional 
yellow excretion ; nor does he show that the proteid in older 
parts might not have been conducted away along the slender 
portions of the hyphae to younger hyphae, as is often the 
case with the hyphae of any ordinary mycelium. Still it is 
quite possible that Frank may be correct in his assumption, 
though not in the dogmatic expression of it as a proven fact. 
But with regard to his analogy of endotrophic mycorhiza 
with an insectivorous plant some remarks are called for. 
A captured insect derives all its food from the outside world 
1 Frank, Lehrbuch, p. 267. See literature given also. 
