by r. greig smith. 455 



The Red Mould. 



When infected upon the surface of nutrient glucose-gelatine 

 the mould, when viewed from above, develops as a white, woolly 

 growth. When seen from below, the surface of the medium is 

 of a bright crimson-scarlet colour. The mycelium grows into the 

 medium to about 5 mm. from the surface, while the colour slowly 

 diffuses to lower depths. The gelatine is slowly liquefied. In 

 faintly acid Hansen's glucose fluid"^ the mycelium grows through- 

 out the liquid but soon covers the surface, producing a crimson 

 velvety layer of hyphae, the colour of which is communicated to 

 the medium. Upon sterilised potato, rice, or sugar-cane, colour 

 is not developed to any extent. The aerial hyph^e are white, 

 while the ground hyphje either remain white or become slightly 

 olive-green. Then pale reddish prominences of h3^phas make their 

 appearance, and as time goes on these are succeeded by black spots. 

 Upon the surface of the potato or cane in contact with the glass 

 wall of the test tube there is a progressive change of colour and 

 variegated patches are produced. 



Fragments of mycelium were sown in small hanging drops of 

 nutrient fluid such as Hansen's fluid and ordinary nutrient 

 bouillon. These sent out septate hyphae, which branched and 

 ramified in a horizontal plane. The refringent growing points 

 of the hyphae pierced the cell walls of neighbouring hyphje which 

 they chanced to meet, thus producing an anastomosing network. 

 In some cases two parallel threads would present a step-ladder 

 appearance. From the ground network, long delicate irregularfy 

 flattened hyph?e were sent into the air; these were sometimes 

 studded with drops of fluid. In the damp chambers, these aerial 

 hyphpe remained as such and never developed conidia or other 

 organs of fructification; they simply existed as sharp-pointed 

 aerial hyphae. Besides these long and practically straight hyphee 

 there developed short, refringent, bent and twisted h37Dhfe. 



* Peptone 10, dextrose 50, potassium phosphate 3, magnesium sulphate 

 2, water 1000. Neutralise with potassium hydrate until 10 c.c. contains an 

 acidity = 1 cc^/jq acid. 



