94 



CHEMISTRY. 



but that alcohol groups were required, indi- 

 cated that in all the cases of apparent direct 

 conversion carbonic acid was first found and 

 became actually free in the soil before assimi- 

 lation took place. Experiments with chloro- 

 phyl-free plants gave similar results. Stut- 

 zer's conclusions were confirmed by Schmoger, 

 who did not, however, regard them as deci- 

 sive. Experiments with such organic matters 

 as are found in the soil have in general given 

 negative results. Experiments by Bohm and 

 Moll seemed to show that plants were inca- 

 pable of producing starch when supplied with 

 carbon only through their roots. Leaves were 

 separated from starch and arranged with the 

 basal end in an atmosphere containing carbonic 

 acid, and the other end in an atmosphere free 

 from it; no formation of starch could be de- 

 tected in the part of the leaf deprived of carbonic 

 acid, although it took place vigorously in the 

 other end. These experiments, as well as the 

 very similar ones of Cailletet, while they do not 

 conclusively show that plants may not assimi- 

 late carbon from organic compounds, do show 

 that under ordinary circumstances and in or- 

 dinary soils the amount of carbon which plants 

 obtain through their roots is, at least, too small 

 to be of any practical significance. 



ANIMAL CHEMISTKY. Eecent experiments by 

 Messrs. Chittenden and Griswold on the dia- 

 static action of saliva under various conditions 

 have revealed the fact that human mixed saliva 

 in the presence of an equal volume of artificial 

 gastric juice containing *05 per cent of hydro- 

 chloric acid is capable of forming, from a given 

 quantity of starch, a much larger amount of 

 sugar than the same quantity of saliva alone 

 can do under a like degree of dilution ; this 

 being the more remarkable, when it is remem- 

 bered that the same percentage of acid by it- 

 self greatly retards the diastatic action. This 

 somewhat curious fact has led Mr. E. H. Chit- 

 tenden, with Mr. J. S. Ely, to study the indi- 

 vidual influence of several bodies of physio- 

 logical importance on salivary fermentation. 

 They directed their attention particularly to 

 the inquiry whether many of the digestive pro- 

 cesses in the body may not be more dependent 

 for their fullest action on the stimulating or 

 other influence caused by the mere presence of 

 many of the digestive products, than has gen- 

 erally been supposed. Several of the products 

 of digestion, it is true, when present in the di- 

 gestive mixture in excess, have been found to 

 retard the digestive process; but there are no 

 facts to warrant the belief that the products 

 of one digestive process necessarily hinder the 

 action of some other allied ferment ; for it is 

 ordinarily understood that any accumulation 

 of the digestive products simply hinders the 

 action of their own particular ferment by 

 clogging the digestive fluid. The results of 

 their experiments show that peptones, a prod- 

 uct of gastric digestion, exercise a decided in- 

 fluence on salivary digestion, stimulating the 

 ferment to increased action, particularly in the 



presence of acid which by itself completely 

 prevents the conversion of starch into sugar. 



The ptomaines, alkaloids produced by the de- 

 composition of animal bodies, appear to have 

 been discovered simultaneously and independ- 

 ently by M. A. Gautier, of France, and Pro- 

 fessor Selmi, of Bologna. M. Gautier detected 

 them in the course of chemical researches; 

 Professor Selmi, while examining the fluids of 

 a corpse in aid of a legal investigation. In the 

 latter case, Professor Selmi detected the pres- 

 ence of an alkaloid that could not be identified 

 with any body whose reaction was known, and 

 confirmed his discovery by repeated experi- 

 ments. Afterward he found, in the scrapings 

 of the skeletons of subjects that had been buried 

 for six and eleven months, fixed and crystal- 

 lizable alkaloids possessing special chemical and 

 physiological properties. Some of them were 

 extracted by ether, others by chloroform or 

 amylic alcohol ; but, unfortunately, they were 

 all yielded in extremely minute quantities. It 

 is established by these experiments that an or- 

 ganic poison may always be found in an ex- 

 humed body, even when the person has not 

 been poisoned. All bodies exhumed a month 

 or two after death, all viscera preserved in 

 bottles with or without alcohol, yield, when 

 treated by Stass's method for the extraction 

 of alkaloids, a certain quantity of ptomaines 

 poisonous to animals that are made to take 

 them. Although the existence and poisonous 

 nature of the ptomaines have been proved, little 

 has been determined concerning their chem- 

 ical nature. Selmi has not isolated a pure 

 ptomaine, nor has he made a salt or an analy- 

 sis of them ; he has only given their reactions. 

 They are bodies of energetic reducing powers. 

 With sulphuric acid they produce a violet-red 

 color, and give out an agreeable odor like that 

 of the hawthorn when heated. In the pres- 

 ent state of our knowledge, we are not author- 

 ized to affirm that these alkaloids have pro- 

 duced poisoning until we shall have been able 

 to isolate them and characterize them individ- 

 ually by the distinctive chemical reactions that 

 are peculiar to them. The presence in a toxi- 

 cological analysis of bodies presenting the gen- 

 eral characters of the cyanic alkalies, and 

 capable, like them, of causing the death of an- 

 imals to which they are given experimentally, 

 can not furnish a presumption of poisoning. 



INDUSTBIAL CHEMISTKY. A new industry 

 has recently been established in the Landes 

 of France, in the extraction and applications 

 of the oils of the pine. Two kinds of oils are 

 extracted from this tree : heavy oils employed 

 for painting and the preservation of woods, 

 and lighter oils for the purposes of illumina- 

 tion. Pinoleum, or the heavy oil of the pine, 

 is obtained by distilling resinous woods at a 

 low temperature. It is composed of essence 

 of turpentine (35 per cent), metanaphth aline, 

 resin-oil, phenic acid, creosote (40 per cent), 

 and coal-tar, benzole, retene, etc. (25 per 

 cent). It is valuable for the injection of 



