13 



unquestioiiably niodifies the toxic action of the gastric juice. An 

 increase in tem perature, above the optimum for ttie fungus, increases 

 the toxicity of the juice to this species. Thus, while tlie juice had 

 no inhibitory effect on the development of spores of Penicilliiim 

 notatum and P. frequenlans at the optimum temperature for these 

 fungi, a rise in temperature to 37^ C. destroyed tlie vitahty of 

 tliese spores but did not kill the spores of the thermophilous 

 species. 



A similar modifying etrect of temperature on the toxic properties 

 of Chemicals has been noted before. Heider (26) found that the 

 toxic action of certain chemicals on the spores of Bacillus anthracis 

 increases with a rise in temperature. Brooks (3) worked with 

 Botrytis vulgaris, Monilia fructigena, Aspergillus niger, Mucor mucedo, 

 and >y Penicillium glaucum», and found that the deleterious action of 

 copper sulphate, sulphuric acid, and nitric acid very rapidly 

 increased with the rise of temperature. The injurious effects were 

 in all instances least at the optimum for the fungus. 



Seen in the light of the above mentioned facts, it appears very 

 probable that the combined action of body temperature (in the case 

 of warm-blooded animals) and gastric juice, kills the spores of fungi 

 with low optimum temperature when these are passing through the 

 alimentary canal. The circumstance that the toxic action of the 

 juice is least at the optimum temperature of the fungus, enables 

 the thermophilous species to pass through alive. The curious fact 

 that none of the extremely common green species of Penicillium, 

 the majority of which have a comparatively low optimum temperature, 

 could be isolated from human faeces, becomes intelligible as well. 

 On the other hand, the presence of these particular species in faeces 

 of xold-blooded animals is to be expected, since the toxic action of 

 the gastric juice cannot be raised to any considerable degree in 

 these animals with low body temperature. The finding of Penicil- 

 lium notatum in lizard and P. frequentans in frog tends to substant- 

 iate this view. 



As was stated above, Weigmann and Wolff (69) found Penicillium 

 breuicaule in the faeces of cow. It is interesting to note that this 

 species grows vigorously at 37^ C. (Plaut 50, Thom 63). Fergusox 

 (14) failed to recover Agaricus campestris in the faeces of rabbits 

 when spores of this fungus had passed through the digestive tract 

 of the animal. If the failure is to be ascribed to the above mentioned 

 facts about the killing of moulds of low optima is not certain, but 



