SENNA. 
197 
A comparison of the statements of authors of repute respecting this active 
principle will show at once the necessity there existed for bestowing further 
labour on the subject. The analyses given by Pereira comprise one by Bra- 
connot of the watery extract of Alexandrian senna, one by Lassaigne and 
Fenuelle of senna leaves, and one by Fenuelle of senna legumes. It will be 
sufficient for my purpose to quote parts only of these analyses. Thus Braconnot 
finds in 104-2 pts. of watery extract of Alexandrian senna 53-7 pts. of the bitter 
matter of senna; as senna is not bitter when unmixed, it is pretty clear that 
Braconnot operated on a sample of senna containing the bitter leaves of Cynan¬ 
chum Argel , without making allowance for the fact. He mentions also 31-9 per 
cent, of reddish-brown gum—a most indefinite term. On the whole, it may be 
said that the analysis is perfectly useless. 
Lassaigne and Fenuelle give a qualitative statement only, at the head of 
■which figures cathartin, a principle (?) found also in senna legumes by Fenuelle. 
This substance is described as being yellowish-red, uncrystallizable, with a pecu¬ 
liar odour and a bitter nauseous taste, very soluble both in water and alcohol, 
but insoluble in ether. Its aqueous solution is precipitated by infusion of galls 
diacetate of lead, etc. etc. Three grains caused nausea, griping and purging. 
Its preparation is thus effected. To a filtered decoction of senna add acetate of 
lead, filter, remove the excess of lead with sulphuretted hydrogen, filter and 
evaporate to an extract, which exhaust with rectified spirit; again evaporate 
to an extract, add a little sulphuric acid to remove potash, present in combina¬ 
tion with acetic acid, and finally purify secundum artem from traces of lead or 
of sulphuric acid if necessary. This substance, which I need scarcely say is not 
worthy of the name of “ active principle,” inasmuch as it is quite destitute of 
“ activity,” and is not a “ principle ” but a complex mixture, long passed muster 
as the so much desired and so often missed senna cathartin ; its discovery was 
announced in 1821. Bley and Diesel pronounced it to be a mixture of resin¬ 
ous and extractive matters; they might with truth have added “derived partly 
from senna, partly from Cynanchum Argel.'" 
In 1845, a prize of 500 francs was offered by the French, for the best essay 
on the chemistry of senna, but an answer not being forthcoming, the offer was 
renewed in 1857, the prize being increased to 1000 francs,—still no response. 
In the same year, however, Marti us gave the subject his attention, and pro¬ 
nounced an opinion that senna owed its activity to chrysophanic acid, a body 
of very stable constitution, and in that respect very unlike what might have 
been expected from senna. Its hitherto acknowledged sources were rhubarb 
and the lichen Parmelia parietina. Martius was controverted by Sawicki, who 
urged the little solubility of the acid. Wiggers, however, came to the rescue 
with a suggestion that the combination of the acid with certain bases would 
give it the required amount of solubility in water. 
In this there is a somewhat near approach to truth ; Martius may be said to 
have u burned,” but he did not “ touch ” the coveted principle. 
Before proceeding to the analyses of senna, published within the last few 
years, I will refer to the notions of the ancients as to the proper modes of preparing 
seuna for administration. It will be found that our remote predecessors were 
net deficient in the power of observation, whatever might have been their defici¬ 
encies in scientific knowledge ; that their practice if not their theory was correct. 
Thus the Arabian physicians held that long boiling impaired its activity, so did 
Culpepper, and cautions accordingly. Heerlein, a modern writer, denies this, 
but not upon satisfactory grounds. Its purgative power is said by some to be 
increased by combining with the senna any simple bitter. The infusum amarum 
purgans and the mist, gentianse co. owe their origin probably to this idea. It 
might even throw light upon the practice (which undoubtedly was not of modern 
invention) of “ adulterating ” Alexandrian senna with the leaves of Cynanchum 
