3° 2 



THE ALUMNI JOURNAL. 



the spectra on both sides of the plate are 

 line spectra. 



From these experiments it would ap- 

 pear that the chlorine atoms in the chlor- 

 ine derivatives of methane are charged 

 with electricity of the same sign as the 

 hydrogen atoms they displace. 



When we can determine the signs of 

 the electrical charges carried by the atoms 

 in a molecule of a compound, we can as- 

 certain whether any given chemical re- 

 action does or does not imply interchange 

 between the electrical charges on the 

 atoms taking part in the reaction. Thus 

 take the reaction. 



CH 4 + Cl s = CH 3 C1 + HC1. 



If we represent the sign of the charge 

 of electricity carried by an atom by+ 

 or — placed below the symbol represent- 

 ing that atom, we may write the last re- 

 action as 



CH 4 + C1C1 = CH3CI + HC1, 



— + +— — ++ + — 



so that this reaction could be produced 

 by a rearrangement of the atoms without 

 any alterations of their electrical charges. 

 If, however, take the reaction — 



HH + C1C1 = 2HCI, 



+— +— +— 



we see that in addition to a rearrange- 

 ment of the atoms there must in this case 

 be an interchange of electric charges be- 

 tween the atoms; for before combination 

 half the hydrogen atoms had a negative 

 charge, and half the chlorine atoms a 

 positive one, whereas after combination 

 no hydrogen atom has a negative charge, 

 and no chlorine atom a positive one. We 

 may thus distinguish between two classes 

 of chemical reactions, (1) those which do 

 not necessarily require any interchange 

 of the electrical charges carried by the 

 the atom, and (2) those which do. It 

 might, perhaps, repay investigation to 

 see whether the occurrence of chemical 



change is affected by the presence of a 

 third substance in the same way in these 

 classes of chemical combination. 



(To be continued.) 



Senecionine and Senecine, mention of which 

 have been made in this column before, are two 

 alkaloids that have been isolated by A. Grandval 

 andH. L,ajoux ("1 Union Pkarm.," XXXVI, P. 

 256) from Senecio vulgaris, a plant belonging to 

 the compositae. Senecionine crystallizes with 

 ease from its chloroformic solution, but the crys- 

 tals are larger when produced from an alcoholic 

 solution. They occur in the form of rhomboi- 

 dal tablets. When kept in a vacuum, or under 

 a bell-jar in the presence of sulphuric acid, they 

 become anhydrous. One hundred parts of 85- 

 per cent, alcohol dissolve o 64 part of senecio- 

 nine at 18 degrees C; it is also soluble in chloro- 

 form, and very sparingly so in ether. It has a 

 bitter taste, and a decidedly alkaline reaction, 

 perfectly neutralizing all acids ; but as yet its 

 salts have not been obtained in crystalline form. 

 It has a rotary power of 80.49 degrees, and a 

 molecular weight, deduced from its saturating 

 power, of 350.87 ; its composition is stated to 

 correspond to the formula C 18 H 26 NO e . 



Senecionine, when treated with potassium 

 ferricyanide and then with ferric chloride, yields 

 Prussian blue. Treated with potassium per- 

 manganate and sulphuric acid, it assumes a 

 violet coloration. It sometimes assumes a pink 

 tint with nitric acid, but this is probably due to- 

 the admixture of a trace of the second alkaloid, 

 senecine. Senecine may be obtained from the 

 alcoholic mother-liquor of senecionine. It is 

 much more bitter than the latter, It is soluble 

 in ether, from which it crystallizes on evapora- 

 tion, in fine silky bundles. Senecine forms 

 with tartaric acid a crystallizable salt, which is 

 but little soluble in cold water, but soluble in 

 boiling water; its crystals are efflorescent. The 

 corresponding seneconine salt has not yet been 

 obtained in a crystallized condition by the au- 

 thors. Senecine gives the following reactions: 

 With sulphuric acid, first a yellow, then a red 

 dish-brown color; with nitric acid, purplish-red, 

 with a deep purple precipitate; sulphovanadic 

 acid produces a purplish-brown coloration. 

 Senecine possesses, in common with senecio- 

 nine, the power of reducing potassium ferri- 

 cyanide, and of producing a violet color with 

 potassium permanganate and sulphuric acid. — 

 Merck's Report. 



