49 



Inoculation Experiments. 



I hâve not SLicceeded in producing canker in cacaotrees 

 by inoculating them with Spicaria. I introduced small 

 pièces of sterilized bark or wood, which had been per- 

 meated by the fiingus, into small woands, which had been 

 eut in the bark of the trees, or between bark and wood, 

 and kept thèse places moist; I experimented in the same 

 way with conidia of Spicaria or of Fusarium. Nor was 

 infection induced by bringing conidia of Spicaria or Fusa- 

 rium on uninjured bark. Experiments in which pièces of 

 diseased bark were introduced into wounds of healthy 

 trees likewise failed. This failure accordingly does not prove 

 anything against Spicaria being the cankerparasite, but 

 leads to the conclusion, that the conditions which rendered 

 the trees susceptible to the disease or which are neces- 

 sary for securing the infection, were not présent. 



Attempts to infect fruits likewise failed. 



Saprophytes. 



After this discussion upon the cankerparasite I think 

 it advisable to deal with some saprophytes, one of which 

 at least very often occurs on cankertrees. It is a Nectria 

 which I at first supposed to be the cause of the disease, 

 the more so as in Ceylon and elsewhere a Nectria is re- 

 garded as such. Moreover nearly always the same form 

 occurred. It was therefore grown in pure cultures. The 

 bicellular spores were sown in hanging drops; they ger- 

 minated readily and produced a mycélium with Fusarium- 

 conidia. A comparison of this Fusarium with the one 

 produced by Spicaria makes it clear at once, that it is a 

 form differing from the above described parasite. 

 1. The shape is différent in several respects: 



a) The Fusarium from Spicaria is more curved than 

 the one from Nectria; 



