8. G. Paine 217 



might well have lost its original parasitic properties. Careful observation 

 will therefore be made next spring for signs of either disease, and it is 

 hoped that the question of identity in etiology may then be definitely 

 settled. 



A disease of Mushrooms has previously been found by Tolaas((i) 

 in which the symptoms were identical with those here described. His 

 description of the causal organism is rather meagre, but in such reactions 

 as are given, except in two instances, there is comjilete agreement with 

 those of the organism described in this paper. The exceptions are in the 

 reduction of nitrates and in the action upon starch (see comparative 

 schedule, p. 218). It is not clear from his brief statement "Nitrates are 

 reduced " how Tolaas arrived at this conclusion, and, in fact, it is possible 

 that both in this and in testing the action of the organism upon starch 

 the methods of technique employed by Tolaas were different from those 

 employed by the authors, and have led them to opposite conclusions. 

 Putting aside these two characters the organisms are closely similar, 

 and, since the symptoms of the disease correspond exactly with those 

 described by him, there seems little doubt that we have here the disease 

 discovered by Tolaas. He suggests that the organism may be a parasitic 

 strain of Pseudomonas fluorescens . This may indeed be the case, but until 

 it is proved it seems well to give the mushroom disease organism a 

 distinguishing name, and, in spite of the slight disagreement in physio- 

 logical behaviour, the organism here described is believed to be identical 

 with that of Tolaas and the name Pseudomonas Tolaasi is suggested. 

 The organism, however, may yet be shown to be identical with that of 

 Barker and Grove, in which case it will be necessary to re-name it in 

 order to give due priority to these investigators. 



Control Measures. Means of controlling the disease have not been 

 investigated for the reason that it subsided and disappeared naturally. 

 Tolaas found an efficient method of prevention of the disease in the 

 fumigation of the beds with sulphur previous to spawning. In this 

 connection it is of interest to note that sulphur fumigation has been 

 the general practice in the houses at Brentford, but was abandoned for 

 the season in which the outbreak occurred. 



