THE TECHNOLOGIST. [March 1, 1865. 



352 ON CHEMISTRY APPLIED TO THE ARTS. 



Kuhlmann have also shown that sulphate of lime acts in a similar 

 manner, namely, that it yields its oxygen to the elements of organic 

 substances, and is thus converted into sulphuret of calcium, which 

 having a great affinity for oxygen is again rapidly converted into sul- 

 phate of lime, and thus the oxygenation and destruction of the organic 

 matter is effected. Mr. Millon has published an interesting paper on 

 the formation of nitre, or nitrate of potash, through the ammonia gene- 

 rated during the destruction of organic substances being oxidised into 

 nitric acid, which combines with potash, if present, and if not with 

 lime or magnesia, which are present in all soils. Mr. Millon has 

 remarked that this important chemical reaction is effected by an organic 

 substance called humic acid, which acid, or its homologues, exists in 

 large quantities in all earthy loams containing much organic, and more 

 especially vegetable, matters in a state of decomposition. Humic acid 

 absorbs the oxygen of the atmosphere, which oxidises the ammonia into 

 nitric acid and water. The chemical theory of the destruction of 

 organic matters through oxidation and their absorption of plants and 

 reconversion into the same substances, from which they were derived, 

 such as sugar, starch, gum, oil, essences, &c, or albumen, fibrine, gluten, 

 caseine, &c, was greatly in favour a few years since, as it appeared to 

 fulfil all the requirements of nature. It has, however, been greatly 

 shaken by the beautiful researches of M. Pasteur on fermentation, 

 putrefaction, and spontaneous generation, which prove clearly that these 

 physiological actions play a most active part in the destruction of 

 organic substances. This most skilful chemist has demonstrated that 

 there is no such thing as spontaneous generation, and that the notion 

 entertained by some physiologists, that if matter is placed in favourable 

 circumstances as to heat, light, &c, and in a proper medium, it will be- 

 come spontaneously animated, is undoubtedly erroneous, and that life in 

 all instances proceeds from a germ or egg in which the vital principle 

 is implanted by the Creator. He proves that life, even in the most 

 insignificant of microscopic creatures, always originates thus, and that 

 there is no single instance of matter being animated by purely physical 

 causes. Let me draw your attention to a few among many facts observed 

 by M. Pasteur, proving that life is not a property of matter, like weight, 

 elasticity, compressibility, &c, but is always the result of a germ even 

 in its lowest development. 



When arterial blood is carefully introduced from the artery into a 

 clean vessel, and there brought into contact with oxygen, no fermenta- 

 tion or putrefaction of the blood ensues ; and if the experiment is repeated, 

 substituting for the chemically prepared oxygen, atmospheric air which 

 has been passed through a tube containing pumice stone and carried to 

 intense heat, in this case also, there is no putrefaction or fermentation ; 

 but if ordinary atmospheric air be used in the place of pure oxygen, or 

 heated air, and left in contact with some of the same blood, this vital 

 fluid will rapidly putrefy, which is doubtless owing to the presence in the 



