An Investigation of a Species of Saprolegnia. 305 
AN INVESTIGATION OF A SPECIES OF SAPROLEGNIA 
By A. E. Lechmere, B.Sc., (Lond.), M.Sc. (Bristol). 
[Plates I. and II.] 
Introduction. 
N January, 1910, a plentiful supply of Saprolegnia came to 
hand, from dead fish in the pond in the Botanical Garden of 
the University of Bristol, and specimens brought into the laboratory 
showed a plentiful crop of zoosporocysts, several of which were 
observed discharging zoospores. I thought this a good opportunity for 
working through the life history of a species of Saprolegnia, and 
the process of isolation into pure culture was therefore at once 
commenced. 
Method of culture and isolation .—The isolation in the first place 
was carried out by means of plate cultures on an extract of beef 
with gelatine after the manner described by Kauffman (’08.) The 
method of preparation, however, was slightly different as by 
repeating his process the haemoglobin was found to coagulate in 
the gelatine. The method then used was as follows: — 
Half-a-pound of beef without any fat was cut up in small 
pieces and extracted with water at 27 n C for four hours ; the whole 
of the extract was then allowed to simmer in a beaker in a water 
bath for half-an-hour, the liquid pressed off and the meat strained 
through muslin. The extract was now boiled for ten minutes to 
completely coagulate all the haemoglobin in the solution, and then 
filtered through filter paper; a clear solution was then obtained 
and this was made up to 1,000 c.c with more water and 100 gm. 
gelatine added. The whole was heated in a water bath till all the 
gelatine was dissolved and then drawn off into test tubes which 
were sterilized by the ordinary method of intermittent heating. 
The Petri dishes used were sterilized by dry heat 120 rt — 140 n C 
for twenty minutes. 
The contents of some of the test tubes was then remelted in 
a water bath and transferred with the usual precautions to the 
sterile Petri dishes. In this way sterilized plates of beef extract 
gelatine were prepared, which were used throughout for all isolation 
processes. 
