87 



fluenced by temperature, and during my experiments the room-temperature 

 was found to lie between 17° and 22° C. 



Now I will make some remarks on each culture, showing the results 

 of my experiments. 



Potassium salts. 



The salts which I chose to experiment with were chloride, bromide, 

 iodide, nitrate and sulphate. 



Control-culture. — On the 7th day after sowing the spores white 

 conidia-fruits were formed. On the 9th they coloured yellow, which changed 

 into dirty brown on the 14th. The average length of conidia-bearing 

 hyphae was 3 mm, their diameter 18 p and the thickness of their well- 

 developed cell-wall 3 a. Ripened conidia-fruits 0.5 mm in diameter, 

 spores 5 a. 



a. Potassium chloride.— -A 5 ^-culture formed white conidia on the 

 7th day after inoculation, which became black on the 9th. This early 

 blackening of conidia distinguished it clearly from the control-culture. 

 Moreover the conidia-fruits increased in size, while the conidia-bearing hyphae 

 somewhat decreased in length. A 10 % -culture produced white conidia 

 on the 9th day, which blackened after two weeks. The particulars of this 

 culture were nearly the same as the former in all respects. A 15 o/ - 

 culture, however, caused not only a remarkable change of reproductive organs 

 but also a retardation of their development. Thus the conidia-fruits from 

 this culture measured 0.18 mm in diameter and the conidia-bearing hyphae 

 0.85 mm in length and 13 u in breadth, a great diminution as compared 

 with those of the normal culture : the appearance of white conidia-fruits 

 was delayed till the end of the 24th day, and on the 31st they were 

 observed to blacken. 



b. Potassium bromide. — A 5 % -culture formed white conidia on the 

 8th day, which changed into dirty brown on the 10th. Compared with 

 the control-culture no distinct change could be seen. A 10 9^ -culture pro- 

 duced white conidia-fruits on the 10th day, which in the course of two 

 days more became brown and black. On the 12th day a 15% -culture 

 presented the first step of conidia-formation. On the 17th the conidia 

 became brown and black. In this culture the conidia fruits as well as the 

 conidia-bearing hyphae decreased in size — the former 0.36 mm wide, the 

 latter 1mm long and 12 jx thick. A 20% -culture showed the conidia- 

 formation first on the 15th day. 



c. Potassium iodide.— A 5% -culture was characterized by a slow 



