THIELAVIOPSIS PARADOX A. 559 



three series of tests, as described below, were carried out 

 separately. With copper sulphate, and in some instances 

 with carbolic acid, where the experiment was prolonged for 

 several weeks, the fungicide and spores, 6y mycehum, was 

 kept in wide-mouthed stoppered bottles. 



Spores were transferred by means of a straight platinum 

 wire to hanging drops of sugar cane extract. They were also 

 transferred by means of a platinum loop to flasks of the same 

 medium. The former was adopted in order to transfer as 

 small an amount of the fungicide as possible with the spores ; 

 the wire was merely dipped in the mixture. In addition, 

 small fragments of mycelium containing spores were trans- 

 ferred to sugar cane extract ; this was done with a hooked 

 platinum wire and as small a quantity as possible was 

 transferred; in general, it did not exceed 0-5 mm. in diameter 

 when collapsed on the wire ; but no exact results can be 

 expected by this last method, since it is usually possible to 

 obtain a germination by transferring a larger quantit}/ of 

 mj^celium. Thielaviopsis is peculiar in that some spores 

 remain within the conidiophores, and apparently these are 

 protected from the action of the fungicide for an indefinite 

 period. 



In making transfers per minute, the mixture was stirred 

 immediately after a sample had been taken and then allowed 

 to settle. In other cases it was stirred shortly before the 

 transfer was made. From observed weights of previous 

 cultures, it was estimated that in no case would the dry 

 weight of a culture exceed • 5 grams ; as a rule the cultures 

 were divided into three, and the mass of spores or mycelium 

 was therefore small in comparison with the volume of the 

 fungicide. In the case of copper sulphate, when the experi- 

 ment was of several weeks' duration, 200 c. c. of the fungicide 

 was used with not more than 0-2 grams (dry weight) of 

 mycehum and spores. 



Mercuric Chloride, 0-1 per Cent. 



(1) As a preUminary experiment, the spores were immersed 

 in this solution and transferred by a platinum loop every 

 minute to flasks of sugar cane extract. The spores transferred 



