1913] GODDARD—SOIL FUNGI 255 
abundant. No manure had been used the year previous, although 
a garden crop had been raised. The entire plat was 20X60 feet. 
This was divided into three equal squares which were treated as 
follows: plat I was untilled and unfertilized; plat II was well 
tilled but unfertilized; while plat III was both well tilled and well 
fertilized with stable manure. Samples of the soil from these 
plats were taken in a manner hereafter described, and cultures were 
made in the laboratory by the usual method, outlined by Duccar 
(32, pp. 34-40). Pure cultures were then isolated and studied. 
CULTURE MEDIA 
Media for the platings and pure cultures were chosen with 
reference (1) to the idea of inhibiting the growth of bacteria, and 
(2) to getting a firm medium on which fungi could be studied con- 
veniently. Two methods were tried: (1) a large percentage of 
gelatin was added to the medium, and (2) the medium was made 
strongly acid by the use of oxalic or lactic acid. The latter method 
was abandoned, proving largely a failure on account of the tendency 
toward liquefaction following sterilization. The first method was 
successful, and was therefore employed for the first platings through- 
out the investigation. The only difficulty in its use was a tendency 
with the mineral salts used to give a precipitate, probably mag- 
nesium sulphate, during the sterilization. Less of this difficulty 
occurred by the use of the steam sterilizer than with the autoclave. 
By the former method a fairly clear medium was obtained, on which 
practically no bacterial growth appeared. _ 
For the pure culture tubes, an agar medium without gelatin 
was found most Satisfactory, on account of the easy liquefaction 
of the gelatin in warm weather. Again, a medium containing 
calcium nitrate instead of ammonium nitrate was found to produce 
more characteristic cultures of some fungi, since with the latter a 
cheesy consistency was developed on the medium, and a slimy 
ctust was often formed over the surface, which interfered with 
the vegetative development. After considerable experimentation, 
three media were finally used: medium 1 was used almost exclu- 
Sively for the first platings; the growth of the fungi was also tested 
on this medium in pure cultures; media 2 and 3 were used ex- 
