374 ANNUAL KECORD OF SCIENCE AND INDUSTRY. 



themselves exclusively by transverse divisions, and occur 

 either isolated or in cell-families." He divides them into 

 four groups or tribes, and indorses Burdon-Sanderson's method 

 of distinguishing bacteria from torulge, namely, that the lat- 

 ter, or fungi- spores, may be transported in the air, while 

 bacteria require a surface of water for this purpose. Bacte- 

 ria have near affinities with alg, and resemble green plants 

 in taking up their nitrogen from ammonia compounds, which 

 animals are unable to do. They diffisr from green plants in 

 not being able to take their carbon from carbonic acid, but 

 requiring carbohydrates and their derivatives, Cohn gives 

 proofs that, practically, a temperature of 176 Fahr. destroys 

 the life of bacteria, and prevents their development in an or- 

 ganic infusion. 18 A^ April 11, 1873, 90. 



THE GROWTH OF SEEDLING PLANTS. 



Dr. J. C. Draper, whose father is well known for his long 

 series of investigations into the chemical properties of light, 

 has recently published, in continuation of his earlier investiga- 

 tions, the result of some observations and experiments on the 

 growth of plants under the action of light, as compared with 

 their growth when deprived of light. He maintains that he 

 has established the proposition that the continuous absorption 

 of oxygen and formation of carbonic acid is an essential con- 

 dition of evolution of structure, both in plants and animals. 

 This opinion is, in so far as it relates to plants, the opposite 

 to that which is commonly held, inasmuch as it has been 

 generally supposed that plants absorb carbonic acid and 

 evolve oxygen in the course of their growth contrary to 

 Draper's idea. The inquiry in reality narrows itself down to 

 the examination of the growth of the plants which contain 

 chlorophyl, or the green coloring matter. Regarding these 

 plants, the statement is generally made that they exhale 

 oxygen under the action of light, and exhale carbonic acid in 

 the dark. Dr. J. C. Draper, following in the path of his father. 

 Professor J. W. Draper, maintains that, in the actual growth 

 or evolution of structure in the plants, oxygen is absorbed 

 and carbonic acid formed, but that the leaves, under the in- 

 fluence of light, absorb carbonic acid, and decompose it in 

 order to produce the gum or other materials that are subse- 

 quently made use of by the plant in the evolution of its 



