TRANSACTIONS OF THE SECTIONS. 29 



acetic acid by isopropyl, and an entirely new series of compounds containing this 

 radical has thus heen obtained. One of these forms a second new ralerianic acid, 



namely, isopropyl-acetic acid, < ^q j? . - The numerous compounds of this 



beautiful series have not yet all been examined and submitted to analysis, and 

 hence these results are still unpublished. 



Taken together, the data furnished by this investigation establish beyond doubt 

 the internal architectm-e of the fatty acids, placing the constitution of these bodies 

 on as certain a basis as that of the compoimd ammonias synthetically investigated 

 by Hofmann. 



" Professor Fraukland has also continued his researches with Mr. Duppa on the 

 sjTithesis of acids of the lactic series. 



M. Persoz and Professor Maxwell Simpson have added still further to our know- 

 ledge on the sj-nthesis of organic acids ; and Professor Hofmann, notwithstanding 

 his engagements in superintending the building of two grand laboratories for the 

 promotion of chemical research, has found time to send us the synthesis of guanidine. 

 Before leaving this subject of synthetical chemistry, I must mention Professor 

 Roscoe's paper on the " Chemical Intensities of Simlight," for this is the direction 

 in which the chemist looks for the glorious climax of all his synthetical investiga- 

 tions — the discovery of the chemical architecture of substances in the vegetable 

 world. 



The next grand field of investigation, analysis, seems comparatively deserted 

 now. A most remarkable discovery has been made by the Master of the Mint on 

 the absoi^ption and dialytic separation of gases by colloid septa ; for example, he 

 finds that mixed gases pass through india-rubber at different rates proportioned to 

 their power of liquefaction. The ox3'gen of atmospheric air passes through rapidly, 

 whilst the nitrogen is comparatively stopped. The importance of this discovery in 

 metallurgy, and its application to the physiology of respiration and of the passage 

 of oxygen from the blood into the textures, must be apparent to all. Mr. Vernon 

 Ilarcourt has begun to estimate quantitatively the effect of time in influencing the 

 amount of chemical change ; or more generally, the laws of connexion between 

 the conditions of a chemical change audits amount. Theu we have new researches 

 on gun-cotton, and a new series of hydrocarbons has been extracted from coal-tar. 

 Some further spectrum analyses have been made by Mr. Iluggius : anaong these 

 are the analyses of comets and of the new star in Coronn Borealis, of which the 

 author will give you his own account ; and lastly, in physiological chemistry we 

 have an important paper on animal heat, by M. Berthelot, being the third memoir 

 of his researches on thermo-chemistry ; and a most valuable work on colouring- 

 matters and extractive matters of the urine, by Dr. Schunck ; and a paper on the 

 detection of nn alkaloid fluorescent substance like quinine in the different structures 

 of the body, by Dr. Dupre and me. 



Pardon my egotism if for a moment I dwell on my own subject, when you may 

 consider other subjects are far more deser\-ing of further remarks. 



It seems but a few years ago when we were taught that the animal and vegetable 

 kingdoms were composed of entirely different kinds of substances. Nitrogenous 

 compounds were said to belong to the animal Idngdomj and the vegetable kingdom 

 was said to be formed of carbonaceous matters only. The annnoniacal products 

 of the gas-works were cousidered curious ; and only from the time of Professor 

 Liebig's investigations do we date our knowledge of the all-pervading presence of 

 albuminous substances in ^-egetables. We can now see plainlj^ that this was the 

 death-blow to aU chemical distinction in the composition of vegetables and animals. 

 But no wrong knowledge is easily set right. lirst starch, then woody Jibre, then 

 colom-ing-matters like indigo, then alkaloids lilfe quinine were one after the other 

 thought to distinguish tlie vegetable from the animal creation, and eacli of these 

 substances or their representatives have at last been found in animals. Even pro- 

 tagon, which was thought to belong only to the nerves of animals, has been found 

 by Hoppe in maize and other cereals to the amount of 0-149 per cent. So that 

 really at the present time no chemical distinction whatever between veo-etables 

 and animals can be made. And except in the mode in which these different sub- 

 stances are produced in the two kingdoms of nature, no chemical difference exists. 



