RUBBER 68 1 



fungus to be the cause of the discoloration. Rubber 

 samples prepared from artificially inoculated latex 

 coagulated with a mixture of 5 per cent, acetic acid and 

 sodium bisulphite developed the typical yellow colour 

 three days after coagulation, whilst controls prepared at 

 the same time were quite clean. 



(2) Violet Flush in Sheet Rubber. 



This flush was present in the sample of sheet rubber 

 showing the yellow flush described above, and was 

 investigated because Bancroft suggested Bacillus vio- 

 laceus as the probable cause. A preliminary examination 

 showed hyphse running through the discoloured area. 



This flush did not appear to be a common one, and 

 even when present was never prominent. Isolation 

 experiments resulted in a species of Fusarium being 

 obtained in pure culture, and artificial inoculations proved 

 this fungus to be the cause of the violet discoloration. 



The investigation of this fungus brought forward a 

 point of some importance. During one series of 

 inoculation experiments with this fungus the artificially 

 inoculated latex was allowed to stand overnight in 

 covered dishes. The following day, on examination, 

 several violet patches covered with a dense growth of 

 white mycelium had developed over the surface of the 

 coagulum. One of these patches was cut out and 

 examined, when the violet colour was found to be due 

 to a layer of typical violet Fusarium spores which had 

 developed over the surface. Thus the typical violet 

 spores were in process of formation eighteen to twenty- 

 four hours after inoculation, when undiluted latex was 

 used as a growing medium. 



In pure culture, however, the typical violet spores do 

 not appear till a considerable time has elapsed. In damp 

 chambers kept under observation for three weeks this 

 type of spore was never formed, and in slant cultures ten 

 days passed before the violet spores appeared. During 

 this intervening period the spores produced were ab- 

 stricted as single cells, which never developed into the 

 typical Fusarium spores. Thus, comparing the life-cycle 



