140 



CHEMISTRY. (VEGETABLE CHEMISTRY.) 



methods. In the discussion following the read- 

 ing of Prof. Prankland's paper, Prof. Burdon- 

 Sanderson advocated the establishment of an in- 

 stitute for research where chemists, biologists, 

 and pathologists could mutually assist one an- 

 other. 



The fact that modifications may be produced 

 in the physiological character of micro-organisms 

 by natural or artificial means, and that they may 

 become inherited and permanent, carries with it 

 an important problem in the identification of 

 bacteria, for the characteristic appearance of an 

 organism may be so modified that its original 

 parentage will be difficult to recognize. A race 

 of sporeless anthrax or asporogene anthrax, pos- 

 sessing the same virulent properties as the origi- 

 nal form, has been produced by Chamberland 

 and Roux, Lehmann, and other investigators. 

 Phisalix has produced sporeless anthrax by the 

 continuous and successive cultivation of anthrax 

 bacilli at 42 C., the process having been con- 

 tinued through twenty-five generations for five 

 months. The twelfth generation yielded a varie- 

 ty incapable of producing spores except on be- 

 ing first passed through the body of a mouse, 

 and the fourteenth generation established a race 

 permanently incapable of producing spores. 

 These asporogene cultures, however, unlike those 

 of Chamberland and Roux, suffered an attenua- 

 tion of their virulent properties, and the descend- 

 ants of the twentieth generation were absolutely 

 harmless as toward animals. The possibility, 

 therefore, of pathogenic microbes losing their 

 virulence, or of harmless saprophytes being 

 trained up to acquire pathogenic properties, is 

 one that must be taken into consideration ; and 

 when it is remembered that sunshine alone may 

 produce such modifications in the physiological 

 development of microbes as permanently to de- 

 prive certain pigment-producing bacteria of this 

 property, and raise up instead a colorless race, 

 the indulgence of this possibility becomes yet 

 more within the bounds of legitimate conception. 



Several observers having noticed that the de- 

 velopment of putrefactive organisms is checked 

 by the combined action of sunlight and oxygen, 

 which was regarded as an outcome of an action 

 excited by the organism, A. Richardson made 

 experiments with urine in order to ascertain 

 whether, when sterilization has been effected by 

 light, any oxidizing agent, such as hydrogen per- 

 oxide, is formed, and whether such substance 

 may not be the sterilizing agent. No hydrogen 

 peroxide is produced by the action of oxygen on 

 sterilized urine in the dark, but an appreciable 

 amount is formed on exposing the urine to light ; 

 the production of the peroxide is hence independ- 

 ent of the presence of organisms. Substances 

 such as manganese dioxide, which destroy hydro- 

 gen peroxide, greatly facilitate organic growth. 

 The addition of hydrogen peroxide to fresh 

 urine renders the liquid much less liable to 

 change under the influence of organisms, while, 

 if added to urine in which fermentation has al- 

 ready set in, the peroxide is rapidly decomposed. 



The micro-organisms comprise chiefly in their 

 constitution substances albuminoid, cellulosic, 

 and mineral substances, which are isolated by 

 incineration which are heavier than water. If 

 the living organisms float in liquids, such as 

 wine, eider, or milk, the specific gravity of 



which borders closely on unity, it is because they 

 probably contain small quantities of gas. Con- 

 sidering the small dimensions of the bodies in 

 question, the force that impels them to rise or 

 sink in a liquid heavier or lighter than their 

 protoplasmic substance is certainly very feeble. 

 The tendency to separation may be intensified 

 by submitting vessels containing fermentable 

 liquids and organisms to rapid rotatory move- 

 ment. The centrifugal force may be rendered 

 several hundred times greater than the force of 

 gravitation. Rotation, according to M. R. Leze, 

 classifies fermentable liquids, and determines 

 the formation of a glutinsms or gelatinous de- 

 posit at the outermost parts of the apparatus 

 employed. On examining the muddy deposits 

 under the microscope they are found to consist 

 chiefly of a heap of living organisms. By this 

 method M. Leze has separated the organisms 

 from a considerable number of liquids in course 

 of fermentation. The organisms appear to sepa- 

 rate the more easily the larger are their dimen- 

 sions. To facilitate the separation, the liquid 

 may be heated, or diluted with liquids lighter 

 than water. This method of separating bacteria 

 may find an application in bacteriological re- 

 search. 



Vegetable Chemistry. Remarking upon the 

 immense variety of substances produced in the 

 vegetable kingdom, E. Warington observes that 

 the plant is the finest chemical laboratory with 

 which we are acquainted. While some kinds of 

 chemical work are common to all plants, there 

 is hardly a species which does not possess some 

 special capacities, which does not produce some 

 compounds different from its neighbors. The 

 extent to which this specialization is carried and 

 the immense variety of the products obtained 

 are truly wonderful ; and our wonder increases 

 when we turn to the materials employed in this 

 work, which are of the simplest kind water, 

 carbonic-acid gas, oxygen, nitric acid, and a few 

 inorganic substances. Out of these the whole of 

 the imnrense variety of vegetable products is 

 constructed. The methods of plant chemistry 

 are of supreme interest to the chemist and to 

 the vegetable physiologist. The higher plants 

 are in some respects unfavorable subjects for the 

 study of plant chemistry. Their different parts 

 have different functions, and the changes in 

 progress are obscured by the fact that changes 

 of a different type are going on at the same 

 time, and in places very near to each other. In 

 bacteria, however, we have the vegetable cell in 

 its simplest form, and the life changes, so far as 

 we know, in all the cells of every species living 

 under the same conditions are the same. More- 

 over, these organisms grow freely in suitable so- 

 lutions, and the chemical changes produced in 

 the materials held in these solutions can be 

 readily ascertained. We have thus -in a study 

 of the chemistry of bacteria a splendid oppor- 

 tunity for enlarging our knowledge of plant 

 chemistry, and, indeed, of becoming acquainted 

 with the fundamental reactions on which syn- 

 thetical organic chemistry depends. The results, 

 so far, of the study of the chemical work per- 

 formed by bacteria have been remarkable. The 

 immensely numerous species of bacteria have 

 been found to exhibit an almost equally great 

 diversity of action, and the study has widely 



