1855.] of Chemiatry to the Preservation of Food. 73 



The decomposing property of the oxygen of the air is most 

 efficient where water is present in a state of minute subdivision. 

 In this case the water (even if it does not promote corruption by 

 itself becoming decomposed,) absorbs from the atmosphere oxygen, 

 which it presents to the decomposable body in a state the most 

 effective for its destruction. " Kain-water, and especially dew, will 

 bring on the putrefaction of animal matters much sooner than spring- 

 water ; and the vulgar prejudice respecting the effect of the moon's 

 rays in accelerating the corruption of meat, is, no doubt, dependent 

 on the fact, that during clear moonlight nights, there is always a 

 large deposition of dew ; and this, having fallen in a minutely 

 divided state, possesses the largest amount of free oxygen which 

 pure or distilled water is capable of absorbing from the atmosphere ; 

 and therefore has a proportionate power of decomposing — just as it 

 also has of bleaching." * 



An interesting illustration of the respective effects of a dry and a 

 moist atmosphere occurs in Sir F. B. Head's " Rough Notes.'* 

 Sir Francis, contrasting the atmosphere of Mendoza, St. Lucie, and 

 Buenos Ayres, (all being in the same latitude,) states that in the 

 two former provinces, " The *air is extremely dry : there is no dew 

 at night, and the dead animals lie in the plain dried up in their 

 skins, so that occasionally I have at first been scarcely able to 

 determine whether they were alive or dead :" but in the province 

 of Buenos Ayres, on sleeping out at night — " I have found my 

 poncho, or rug, nearly wet through with dew ; the dead animals in 

 the plain are in a rapid state of putrefaction/'j" 



3. Decomposition of a moist organic body may be prevented if 

 air be entirely excluded. 



" Gay-Lussac found that when bruised grapes were carefully 

 excluded from the air, no change ensued ; but that even a 

 momentary exposure of the pulp to air or oxygen was sufficient to 

 communicate to it the power of fermentation. "{ — A bottle was 

 exhibited, containing a piece of meat and a stick of phosphorus. 

 They had remained together since January 15, 1855. The meat 

 appeared fresh, but the phosphorus was visibly oxidized and acidified. 



Application of these principles to the Preservation 

 OF Food. 



A. Principle of desiccation at a temperature below that which 

 would cause the albumen to coagulate. 



Animal and vegetable substances dried in the sun, or at a low 



* On Preserved Meats for the Naval Service. — Newton's London Journal, 

 Vol. xl. p. 200. 



t " Rough Notes," &c. 2nd FaI. p. 8. Vide also on same subject, p. 142. 

 Also Murray's " Handbook for Travellers on the Continent." Gth Ed., p. 268, 

 on the preservation of the bodies of the monks at Kreuzberg. 



t " Brande's Manual," Vol. ii. p. 1640. Gth Ed. 



