132 
Transactions, &c. 
r Monthly Microscopical 
L Journal, Sept, 1, 1869. 
had unfortunately written no paper on the subject, though he had 
had a diagram, exhibiting his leading results, lithographed and 
coloured, to accompany a reprint of the intended memoir after pub- 
lication. This chart, with the following extract from a letter to 
his friend, J. E. Howard, Esq., of Tottenham, will suflBice to rescue 
from loss Dr. Herapath's last scientific work. 
Extract from Letter. 
" June 27th, 1868. 
. . . " I have found results of very considerable interest in the last 
consignment you sent me. There are three solutions of the chlorophyll 
of the Cinchona Succirubra. One in alcohol is scarcely coloured, having 
in fact a tinge of olive-green. This in the spectroscope was perfectly 
marvellous to me. It gave four well-marked absorption-bands, one 
deep sharp line in the red ; another, rather narrower, in the orange, 
coincident with D, or the sodium-line ; one in the green, about h, 
coincident with the Thallium green band ; and a fourth on the blue 
line F, nearly as broad as that in the red. The ethereal solution 
gave diderent results. It showed only three bands of absorption, 
nearly the same as in the last case (though all of them fainter) ; but 
the fourth in the blue was not apparent, the whole of that end of the 
spectrum being absorbed a little beyond the green band h. This 
solution was deep emerald-green, and even on dilution did not alter 
its phenomena. The acid alcoholic solution was as deeply green as 
the last, but gave only the sharp broad absorption-band in the red, 
and two very faint ghostly bands in the position described above of 
the D and h lines respectively. 
" Extensive additional researches on the chlorophyll of various 
plants have given some very extraordinary results, which I am now 
working out. The chlorophyll was dissolved out by Spiritus Vini 
Meet., digested for some hours in the cold ; some plants being fresh, 
and others dried. 
" Five classes of phenomena exhibit themselves, but all agree in 
having the red absorption-band broad, sharp, and well-defined. Some 
have this one band only : the Lilac is of this type. 
" There are two classes in which two absorption-bands occur. One 
has the red and the orange bands, of which the Fuschia, Guelder-rose, 
and Tansy are examples ; another, in which the red and the green 
bands are alone coexistent. Ivy is the type of this class, and it is 
immaterial whether we take last year's leaves or those of the early 
spring ; the results are the same. 
" The fourth class consists of the two former spectra superposed. 
Three lines occur, the red, the orange, and the green bands, at C, D, 
and h, as before. This is by far the largest class, and I have thirty or 
forty examples of it. CEnothera biennis, Laurestinus, &c., are types, 
with the ethereal solution of the leaves of Eed Bark. 
" The fifth class consists of those having properties similar to the 
alcoholic solution of Red Bark before described. I have only found 
eight of these as yet, and not all equal in power, namely : — Berberry 
