BIOLOGY OF ALEURODISCUS 
455 
In 1913, Lowschin (16) showed the numerous points of similarity 
between chondriosomes and myehn forms produced out of lecithin in 
different salt and albumin solutions under the conditions that lead to the 
formation of lecithinalbumins. Of the filaments observed, he says (p. 204) : 
"Die langen Faden, Spermatozoidformen und dergleichen bilden sich, wenn 
in der umgebenen Fliissigkeit Strome existieren; die Ursache dieser Strome 
mag verschieden sein." 
Dangeard (6), in studying both living and fixed cells of Saprolegnia 
as well as of other plants, finds a canalicular system throughout the cyto- 
plasm which he considers a nourishing apparatus, containing in colloidal 
solution of greater or lesser density substances of which the chemical 
nature has not yet been determined, but doubtless related to lipoids. They 
have the general character of blackening with osmic acid, and possess 
the same osmotic and elective properties as the metachromatin. They are 
precipitated in the form of solid granular or filamentous bodies under the 
influence of absolute alcohol and certain other reagents. 
Speaking only for fungous tissue, we may conclude that many of the 
structures that have been described in the cytoplasm as morphological 
structures, mitochondria, metachromatic bodies, extranuclear chromatin, 
and the like, fall into a category of coagulation products resulting from a 
complex and variable fluid substance in the protoplasm that has the property 
of reducing osmium tetroxide and chromium salts and that is coagulable 
into definite structures. The tendency has been in general to interpret these 
structures from the morphological rather than from the physiological 
viewpoint. 
Summary 
1. Aleurodiscus amorphus was collected on twigs and small branches of 
fallen balsam firs in the Adirondacks. Because of the large cells in the 
hymenium, it proved to be excellent material for cytological study. It is 
often parasitized by a Tremella which may completely cover and conceal 
the fruit bodies of the host. This is compared with other Tremellas that 
are associated with the fruit bodies of other fungi. 
2. The mycelium of the Aleurodiscus grows throughout the intercellular 
spaces of the bark parenchyma of the twigs and small branches. The fruit 
body begins its development as a mass of densely interwoven hyphae 
within the lower tissues of the bark. There is an upward growth of the 
hyphae, and they emerge through the ruptured corky and epidermal layers. 
Here they branch and expand into the characteristic fruit body that is 
typically convex but may be more or less pezizoid in form. The hymenium 
is characterized by the nodulose paraphyses. 
3. In the cytoplasm fixed with osmium and chromium fixatives, large 
filaments and numerous granules appear, which are thought to be in a class 
with mitochondria, metachromatic bodies, and other morphological struc- 
