193 
of Edinburgh^ Session 18G9-70. 
from each other, and it is the intention of the author to work in 
this direction. It is observed also that indol, the nucleus of 
indigo, is benzol-pyrrol, being related thus, 
Indol. 
Pyrrol. 
C 6 H 4 
CA 
NH 
NH 
C>A 
CA 
It is therefore likely that indol may be met with along with pyrrol 
among the products of the destructive distillation of nitrogenised 
organic substances. While this paper is passing through the press, 
Professor Baeyer of Berlin has pointed out, independently, a simi- 
lar relation between pyrrol and indol, a note of which has just been 
published. 
7. Notes of some Experiments on the Eate of Flow of Blood 
and some other Liquids through tubes of narrow diameter. 
By J. Matthews Duncan, M.D., F.E.S.E, and Arthur 
Gamgee, M.D., F.E.S.E. 
The experiments, of which the results are recorded in the present 
communication, were undertaken in order to determine the rate at 
which blood flows through tubes of moderately small diameter, with a 
view to the study of the mechanical theory of dysmenorrhoea ; they 
were afterwards extended to blood-clot, serum, milk, and urine, &c. 
In a memoir inserted in the ninth volume of the “ Memoires des 
savants etrangers,” M. Poiseuille stated the results of an investiga- 
tion on the flow of water and other fluids through capillary tubes, 
showing how this is influenced by pressure, by the length and 
diameter of the tube, and by temperature. A committee of the 
French Academy, of which M. Begnault was the reporter, corrobo- 
rated the results of M. Poiseuille’s researches.* Subsequently this 
observer published a still more extended series of observations, in- 
cluding the determination of the rate of flow T of serum and defi- 
brinated blood.t 
* Recherches experimentales sur le mouvement des liquides dans les tubes 
de tres-petits diametres. Commissaires MM. Arago, Babinet, Piobert, Reg- 
nault rapporteur. Academie des Sciences, seance du 26th Decembre 1842. 
t Recherches experimentales sur le mouvement des liquides de nature dif- 
ferente dans les tubes de tres petits diametres par M. le Dr Poiseuille. An- 
nales de Chimie et de Physique. Troisieme serie t. xxi. 1847. 
