Polytechnic Association. 579 



IY. Comparative experiments show that a given volatile agent is 

 far more efficient when it is contained in the air supplied to a putres- 

 cible solution than when an equal quantity is mixed with the solu- 

 tion itself. 



Y. All fungoid organisms can be prevented by the presence of a 

 minute proportion of creosote, carbolic acid, ammonia, hydrochloric 

 acid, or sulphurous acid in the air, though beneath the surface of the 

 fluid are found numerous bacteria and vibrios. 



There seems to be no escape from the conclusion that the germs or 

 fungi exist in the air and are destroyed by the volatile, poisonous 

 agent. ■ N 



Mr. R. D'Heureuse said that the phenomenon of putrefaction was 

 very generally confounded with that of fermentation. Some agents 

 would prevent the one process and assist the other. Atmospheric air 

 actively promotes fermentation, and at the same time destroys putre- 

 faction or decay. 



Dr. P. H. Yan der "Weyde — Scientists distinguish between different 

 kinds of changes which may be grouped together under the general 

 term fermentation. We have the alcoholic and the acetic fer- 

 mentation, very different from each other, but requiring the same 

 agents at different temperatures. Putrefaction is the last in this 

 general series of fermentations. The alcoholic fermentation is the 

 least destructive, but they are all destructions of organic elements. 

 By the alcoholic fermentation the starch is first changed into grape 

 sugar and then into alcohol. By the acetic fermentation the alcohol 

 is changed into vinegar. Some agents which will prevent one kind 

 of fermentation will promote another kind, because they require dif- 

 ferent conditions. The two theories spoken of in this paper appear 

 to turn upon the question, which is the great question of the age, of 

 spontaneous generation ; for if we admit the existence of spontaneous 

 generation we do not need those theories. 



Mr. D'Heureuse — I do not wish to be misunderstood. The alco- 

 holic process is a perfectly healthy action ; and what is called the 

 acetic fermentation is really an oxidation ; but putrefaction is a pro- 

 cess of decay. 



II. Yaluable Australian Timber. 



Two kinds of wood indigenous to western Australia have recently 



attracted considerable attention, from the fact that they possess 



qualities not found in the common woods of our forests. The Jar- 



rahjarrah timber is very hard, and capable of receiving a high polish. 



