68 FUNGI. [CH. Ill 



SECTION B. Nutrition of Fungi 1 and of Drosera. 



(80) Method. 



Make the following 2 nutritive solution (N). 



Dextrose 5 to lO'O grams 



Peptone 1 to 20 



Ammonium nitrate I'O 



Potassium nitrate 0*5 



Magnesium sulphate crystals 0*25 

 Potassium monophosphate 25 



Calcium chloride O'Ol 



Pure water 100 



Take 1000 c.c. of solution N and add to it 100 grains 

 of pure gelatine (Coignet's gold label) ; sterilise in a flask 

 plugged with cotton-wool, filter while hot and distribute 

 into sterile plugged tubes : sterilise and preserve for use. 



Expose a saucer of solution N to the air, until it is 

 infected with one of the blue moulds : Penicillium or 

 Aspergillus. With a sterilised needle remove spores of 

 the mould selected and shake up in a small flask of pure 

 water : rapidly filter through a sterile funnel, plugged with 

 cotton- wool to make the spores separate from one another. 

 Add one drop, or more, according to the quantity of spores 

 in the water, to a tube of the gelatine just liquefied, and 

 pour it into a sterile glass dish. When set, put it aside 

 at 20 C. in the dark ; after 48 hours or so there will 



1 For the form of the instructions here given we are indebted to 

 Professor Marshall Ward. 



' 2 Or any of the solutions given on p. 172 of Zopf, Die Pilze. 

 Solution N is compiled from Elfving, Studien iiber die Einwirkung do 

 Lichtt anf die Pilze, 1890, p. 30. 



