tHIELAVIOPSIS PARADOXA. 519 



a Sucre, niais lorsque celle-ci est tuee depuis longtemps et que 

 les contenus cellulaires ont entierement disparu." It is 

 evident from the context that " le mycehum " refers to the 

 mixed mycehum in the naturally diseased sugar cane, and not 

 to the mycelium produced by artificial infection ; they did 

 not succeed in reproducing the Conioihyrium, or any other 

 form, in artificially infected cane, nor did the latter decay to 

 any marked extent. 



Hoivard. 



Howard's investigations were carried out in Barbados, 

 with the object of deciding the disputed life history of 

 TricJiosphoeria sacchari. As the result of an extensive series 

 of cultures, he stated (10) that all attempts to produce Thiela- 

 viopsis from Mdanconiiim spores in sterilized media failed, 

 but that he was able to secure the desired result by inoculating 

 unsterilized pieces of sugar cane. In a later communication 

 (11), however, he states that he was unable to repeat this 

 success, and admits that the sugar cane used was probably 

 previously infected. He was not able to find the perithecia 

 of Trichosphceria sacchari on dead canes, nor to obtain it in 

 his cultures. He concludes that the whole of the evidence 

 obtained points to the Melanconium being quite distinct from 

 Thielaviopsis. 



Cultures of mixed macro- and micro-conidia of Thielaviopsis 

 on sterilized cane slabs produced a white mycelium in twenty- 

 four hours ; they turned black in three days owing to the 

 formation of large numbers of microconidia and a few macro- 

 conidia. The same result was obtained in plate and flask 

 cultures. 



The development of the spores was studied separately in 

 hanging drops. The macroconidia " germinated in five hours 

 after sowing, and in eleven hours the hypha commenced to 

 branch. In eighteen hours the drop was filled with a 

 branched septate colourless mycelium, which exhibited very 

 rapid growth. In twenty-four hours some of the hyphse 

 commenced to grow down into the air, especially round the 

 margin of the drop. This behaviour soon became general all 

 over the drop. The aerial mycelium appeared ohve in colour, 

 and grew with great rapidity. One of these aerial hyphae was 



