173 
1. Mg+HO+S0, = Mg0,80, + H 
2. 2Mg+8S80, = Mg0,S0, + Mg0,8,0, 
3. 4 Mg+8SO, = Mg0,SO, + Mg0,S,0, + 2(Mg0,8,0,) 
These reactions seem to take place according to concen- 
tration, and depending in general upon conditions, which 
a future and closer study may reveal,and in the investiga- 
tion of which, I hope other chemists will participate. 
The following paper was read, 
“ Note on the Absorption Bands of Hematin and Cruorin,” 
By A. H. GAnLatr. 
The author, after alluding to the attacks of Dr. Forbes 
Winslow, of Steinmetz, and more especially of Paul Bert, on 
the reliability of spectral observations generally, and of 
observations connected with the absorption spectrum in par- 
ticular, proceeded to defend the use of the spectroscope as 
an adjunct to the microscope, and to chemical analysis in 
medico-legal investigations connected with blood stains. The 
investigations of Hoppe-Scyler, of Valentin, of Stokes and. 
of René Benoit, on the action of oxydizing, reducing and 
decomposing agents in producing the characteristic bands of 
Heematin, Cruorin and Heemin, in the absorption spectrum 
of blood, were briefly described, and it was pointed out how 
these phenomena enabled us to distinguish solutions of 
colored organic matter of other origin than blood from blood 
itself. Moreover it was claimed that by these methods, we 
could study phenomena, such as the nature of Cruorin, and 
the question of its solubility and of its transformation by: 
reagents, which we cannot approach by purely chemical 
means. The author studied the comparative spectra of 
Cruorin, and of a solution of carmine in ammonia, and dis- 
covered that their respective absorption bands were colored 
and shaded so differently, that by superposing the two spectra’ 
by the aid of two prisms near the slit, we could readily dis-’ 
tinguish the one from the other. The appearance of thése’ 
PROG, LYC. NAT. HIST. N. Y.—VOL. L 12 
