EXPERIMENT STATION BULLETINS. 



281 



These tables confirm the work with specific micro-organisms and demonstrate that 

 there is no uniformity in the results obtained on studying the interchange of gases 

 due to the fermentations induced by bacteria. Usually oxygen entirely disappears and 

 carbon dioxide increases in amount, still it is found that traces of oxygen remain in 

 some cases of air confinement over milk even after many hours. Unless there is 

 inducted fermentation, there can be no elimination of carbon dioxide and decrease of 

 oxygen. Further, after milk reaches an age where bacterial growth is abundant there 

 can be no correct study of the gas-content of milk. 



Thorner and Blyth have further demonstrated that as fermentation sets in the 

 carbon dioxide increases and oxygen may totally disappear. 



It is apparent therefore that micro-organisms enter intimately into the production 

 of carbon dioxide and the absorption of oxygen after fermentation begins. This may 

 be checked by the use of antiseptics in milk. 



XI. ACTION OF ANTISEPTICS UPON THE INTERCHANGE OF GASES BETWEEN MILK 



AND AIR CONFINED OVER IT. 



Attempts were made employing chloroform, ether, formaldehyde, but without success 

 because of their interference with the gas analyses. 



Mercuric chloride and salicylic acid were also used but they were not satisfactory. 

 Lysol gave us the most trustworthy results. 



TABLE IX. 



ACTION OF LYSOL UPON GASEOUS INTERCHANGE IN MILK. 



From this we gather that some oxygen has been absorbed as is indicated by the 

 lower percentage. It may be, however, that the carbon dioxide, had any been evolved, 

 was absorbed by the alkalinity of the lysol. This element of error may be overcome 

 by the use of trikresol, a neutral substance, which yielded these results: — 

 36 



