CURRENT. LITERATURE 
NOTES FOR STUDENTS 
Mucor and Chaetocladium.—BurceErFF' has given an interesting account 
of the relations between the parasite Chaetocladium and the host Mucor. 
The Chaetocladium investigated reacts physiologically like C. Fresenianum, 
but morphologically more like C. Brefeldi, although its spores are larger than 
in the latter species. The Mucor host was a variety of Mucor mucedo which 
Burcerr describes as Mucor mucedo dependens. 
The course of infection was followed in both fixed and living condition. 
Fortunately the plasma of the parasite stains more deeply than that of the 
host, so that host and parasite can be distinguished in sectioned material. 
When growing together the filaments of the Mucor host are attracted by those 
of Chaetocladium. Filaments of the parasite apparently are not attracted by 
those of the host until they are within a very short distance of each other. 
Contact of the two kinds of filaments is a stimulus which causes a slight 
thickening of the tip of the Chaetocladium hypha, inhibits its growth in length, 
and finally causes the formation of a cross wall cutting off the terminal portion 
of the filament of the parasite, which becomes the gall cell. The adjacent 
walls of the host and parasite dissolve, and plasma and nuclei of the host enter 
the gall cell, which at once swells and branches. In the gall cell the nuclei 
of the host are arranged peripherally and undergo division, while those of the 
parasite are centrally located and apparently do not divide. The gall cell is 
termed heterocaryotic (or a mixochimaera), since it contains two kinds of 
nuclei in contrast with the homocaryotic hyphae of the host and of the 
parasite. It is in open communication with the host hypha, but separated 
from the parasite by a membrane. Some of the branches from the primary 
gall are heterocaryotic and some homocaryotic, containing only Mucor nuclei. 
These latter branches form secondary galls in contact with pure Chaetocladium 
host plasma. Branches of Chaetocladium from below the gall intermingle 
with those of the latter, thus increasing the area of contact between the gall 
and parasite. Apparently it is only at contact surfaces between the hetero- 
caryotic gall and the Chaetocladium hyphae that diffusion to the advantage 
of - ees can take place. At any rate, after contact of Chaelocladium 
2 onee , H., Uber den Parasitismus des Chaetocladium und die heterocaryo- 
tische Natur ic vonihmauf Mucorineen erzeugten Gallen. Zeitsch. Botanik 12:1-35. 
Jigs. 36. 1920 
is 
