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TUESDAY, APRIL 3rd. 



A Lecture was delivered on "Tlie Conservation of Energy in 

 Organic Nature," by W. Lant Carpenter, Esq., B. A., B.Sc, F.C.S. 



The doctrine of the Conservation of Energy is one of the 

 grandest generalisations of modem physical science. The first 

 treatise on the subject was by Sir W. Grove, and the first hint 

 that the doctrine was applicable to the organic world came from 

 Dr. Mayer. 



The Lecturer first glanced at its applications in the physical 

 world. Energy is the "power of doing work," and the various 

 forms of energy, such as mechanical energy, electrical energy, and 

 so on, are interchangeable ; each can be converted into any other, 

 either immediately or mediately. Energy is never diminished in 

 amount, nor is it increased. The energy of a railway train, when 

 brought suddenly to a standstill, is not lost ; it is converted into 

 heat. 



Under the influence of the "radiant energy" of the Sun, the 

 cells of plants decompose the carbonic acid of the air, appropriate 

 the carbon for their own growth, and set free oxygen. At the 

 same time the root-cells absorb water, as well as the mineral 

 matters ammonia, phosphates, &c., dissolved therein. The energy 

 thus appropriated is stored up, and when the wood and resin in 

 the plant are burned, it is recovered in the shape of light and heat. 

 Coal is the remains of huge forests of trees which grew many ages 

 ago. It is even now forming in the " Great Dismal Swamp " in 

 Virginia, U.S.A., and in other parts of the world. 



A broad distinction between animals and plants is that animals 

 cannot (as plants do) derive their food from carbonic acid, ammonia, 

 and water ; they require to have these substances decomposed for 

 them, and elaborated into food-compounds, by plants. Heat is 

 necessary to maintain the vital processes of a warm-blooded animal ; 

 death by starvation is really death from cold. Man's food consists 

 essentially (1) of starch, sugar, &c. ; (2) of fats and oils; and (3) 

 of albuminoids, such as the gluten of bread, the fibrin of meat, 

 and the casein of cheese. The first and second of these classes 

 Qontain carbon, hydrogen, and oxygen only, the other contains 



