365 
Life-history of Parasitic Ftcngi. 
abundant, and was much less than in the cultures of Hormode?idron. Soon 
conidia of Cladosporium began to be formed ; they were found to arise 
in a similar way to those described above in the cultures of Hormodendron. 
On germination these conidia gave rise to conidia of Cladosporium again. 
The following conclusions are based on the comparison of the cultures 
of Cladospormm and Hormodendron :—the characters of the mycelium and 
of the component hyphae are similar in both cases ; there is a production of 
conidia of Hormodetidron which is more abundant in the latter case than in 
the former; this is followed in both cases by the formation of conidia 
of Cladosporium , and these conidia of Cladosporium on germination repro¬ 
duce themselves ; of the two conidial forms, Cladosporium and Hormodendron , 
each can give rise to the other and each can also reproduce itself; the 
tendency on the part of Hormodendron in an artificial matrix to pass to 
Cladosporium is clear. 
The effect of a lower temperature on the germination of conidia 
of Cladosporium. 
In the experiments described above, in which £ hanging-drops ’ were 
employed, the conidia of Cladosporium had been germinated at the 
temperature of the laboratory, i. e. at 6o° F. and above, and it has been 
shown that they always gave rise to conidia of Hormodendron . Further 
experiments were conducted for the purpose of ascertaining whether 
a lower temperature would in any way influence the formation of conidia 
of Hormodendron. The hosts used were Cabbage, Catalpa , and Funkia ; 
one or two conidia from each were mounted in a ‘ hanging-drop 5 in a 2 per 
cent, solution of cane sugar. The ‘ hanging-drop ’ cultures were placed on 
a box outside of the building, and near to them were placed a maximum 
and a minimum thermometer. During the space of five days the ther¬ 
mometer recorded the following temperatures :— 
Date. 
Maximum 
Temperature. 
Minimum 
Temperature. 
November 10 
49 ° F. 
35 ° F. 
„ 11 
50° F. 
32 ° F. 
» 12 
55 ° F. 
33 ° F. 
„ 13 
54° F. 
30 ° F. 
>> 14 
56 ° F. 
31° F. 
The highest temperature attained was 56° F. on the last day, and the lowest 
temperature was 30° F. on the fourth day ; the average temperature for the 
five days was 42° F. All of the conidia germinated, and each gave rise to 
hyphae which were septate at somewhat short intervals, were sparingly 
branched, and bore conidia of Cladosporium. In some cases not only were 
the conidia borne at the tip of the hypha, but the hypha became converted 
