CHEMISTRY. (BACTERIOLOGICAL CHEMISTRY.) 



week. Siiiiilur tubes were treated with the water 

 tin- addition of the iron solution, and 

 in every case followed in eighteen hours. 

 Tin- t-x|M -riments were repeated at intervals over 

 a pi-rind of two years, and always with the same 

 results Th.' process has been employed in pub- 

 lic insiitutioiis and private houses in the Lee- 

 \\anl Islands, with apparently good results. 



Sudimn peroxide is used as an analytical agent 

 by .1. rlark. who finds that by heating powdered 

 minerals with it, the arsenic and sulphur may be 

 made soluble. 



( liemical Synthesis. The fundamental hy- 

 pothesis which has guided Raoul Pictet in his 

 experiments in chemical synthesis, and the ex- 

 perimental variations of it, have enabled him to 

 establish eight laws: 1. At very low tempera- 

 t u res (l>elow 130 C.) no chemical reaction takes 

 place, whatever substances are present. 2. All 

 chemical reactions are manifested spontaneously 

 at a certain temperature and under a certain 

 pressure exerted upon the constituents; this is 

 the temperature limit. 3. The same reactions 

 may be obtained below the temperature limit if 

 we apply auxiliary energy by the use of electric 

 currents or discharges. 4. Exothermic reactions 

 always present two phases : in the former we re- 

 tain a control of the temperatures if we can re- 

 move from the combining bodies by radiation as 

 much heat as is produced at the same moment 

 by the simultaneous effect of the affinities of the 

 extraneous energies introduced into the sub- 

 stances ; in the second phase, the temperature 

 rises suddenly until the reaction takes place 

 above the temperature limit. The first phase is 

 the reaction limit ; the second phase is the re- 

 action in mass. 5. Endothermic reactions are 

 always limit reactions. 6. The dissociation of 

 the products obtained by exothermic reactions 

 corresponds to the laws of endothermic combina- 

 tions, and reciprocally. 7. The temperature limit 

 of chemical reactions is not in a known simple 

 relation with the apparent energy of the phe- 

 nomenon ; on the contrary, the quantities of 

 heat liberated seem to class the ascending order 

 of the temperature limit, especially in one and 

 the same family of substances. 8. The electric 

 spark and current seem to be the best media for 

 supplying extraneous energy to limited chemical 

 reactions. With these eight practical laws we 

 may establish a complete scientific programme 

 for the discovery of a general method of chem- 

 ical synthesis. We begin by bringing in contact 

 the simple bodies, and defining experimentally 

 the laws which govern their combinations. Next 

 we shall study combinations of the binary com- 

 pounds, ternary substances, etc., to constitute our 

 dynamic tables'. The successive experiments will 

 discover the laws which govern the phenomena, 

 and chemical reactions will be defined precisely 

 and certainly. The present experimental results 

 give a preliminary sanction to this programme. 

 Bacteriological Chemistry. Speaking in 

 the British Association of "The Present Position 

 of Bacteriology," more especially in its relation 

 to chemical science, Prof. P. Prankland showed 

 that microscopical characteristics, even under 

 favorable circumstances, were insufficient for the 

 recognition of bacteria ; consequently morpho- 

 logical methods have had to give way to chemical 

 and physiological tests. Chemical tests, being 



as yet few in number, are apt to be treacherous, 

 but they are capable of considerable extension. 

 The typhoid bacillus, for example, will give no 

 reaction with indol, such as is characteristic of 

 the cholera bacillus, and will not ferment glu- 

 cose, but will coagulate milk. With regard to the 

 chemical products of the action of organisms, the 

 questions suggest themselves, Does the same sub- 

 stance yield different products with different 

 bacteria f Do the same bacteria give rise to the 

 same products with different substances! Ex- 

 periments with pure cultures have shown that 

 the same bacillus will give identical products 

 with such chemically related bodies as glycerol, 

 arabinose, mannitol, etc. It is probable that fer- 

 mentability is due to the p6*wer possessed by a 

 set of substances of yielding the same intermedi- 

 ate body which will give identical end products 

 in all cases. This may explain why only those 

 sugars which contain three carbon atoms or a 

 multiple of three in their molecule appear to be 

 fermentable. The production of all three vari- 

 eties of lactic acid by fermentation of glucose by 

 different organisms has been accomplished. The 

 problems of selective fermentation were next 

 dealt with. Its cause was to be sought for in 

 the slight differences of solubility, etc., shown by 

 active substances when in combination with op- 

 tically active isomeric bodies. One isomer is not 

 found always to be quite unfermentable ; in some 

 cases both isoiners can be destroyed if time be 

 allowed, one, however, always disappearing first. 

 Of great interest is what may be called educa- 

 tional culture, by means of which new character- 

 istics may be artificially impressed upon an or- 

 ganism. A species of bacillus morphologically 

 identical with anthrax, but incapable of produc- 

 ing spores, may be obtained by cultivation of true 

 anthrax in broth containing certain salts, such 

 as potassium dichromate or nitrate. The new 

 characteristics will even persist after passage 

 through the bodies of animals. On the other 

 hand, by various means the virulence of patho- 

 genic organisms can be greatly increased, though 

 it has not been found possible to produce patho- 

 genic from n on pathogenic organisms. It be- 

 comes probable, therefore, that naturally occur- 

 ring bacilli will acquire new characteristics 

 according to alterations in the conditions of 

 their growth. The occurrence of nontoxic as- 

 sociated with certain toxic organisms for ex- 

 ample, those of diphtheria, anthrax, cholera, and 

 typhus is suggestive in connection with this fact. 

 It is possible that aerobic organisms may become 

 so far modified as to be active in the absence of 

 air. Much study is wanted in this direction. 

 Speaking of the disinfecting action of light under 

 different conditions, Prof. Frankland said that 

 the generation of hydrogen peroxide from air 

 and moisture under the influence of light, dis- 

 covered by Richardson, seemed to play an im- 

 portant part in this action of sunlight, and the 

 problem partly resolved itself into the study of 

 the conditions of formation of this substance. 

 The effect of different salts in modifying the 

 bactericidal effects of sunlight was touched on, 

 and, in conclusion, the necessity was urged upon 

 chemists of a knowledge of bio'logy anci botanv, 

 to enable them to carry on bacteriological work, 

 for which the first necessity had now become pro- 

 found knowledge of chemistry and chemical 



