SECTIONAL TRANSACTIONS .—I. 369 
Prof. J. A. MacWixu1am, F.R.S.—The regulation of the heart-beat and 
blood pressure, with special reference to the effects of posture (3.45). 
Postural effects on the circulatory system are related to : 
(1) Attitude, per se. 
(2) Tonic muscular contraction involved. 
(3) Stretching and compression of certain muscles. 
Quite different mechanisms are concerned in the pulse-rate differences 
in standing, sitting and lying—the carotid sinus reflex on changing from 
sitting to lying, and the positions of the thighs in standing and sitting. 
The buffer nerves and especially the carotid sinus reflex play a very 
important part. This reflex varies greatly in responsiveness from time to 
time and with motor effort, emotion, etc. ; several other vascular reflexes 
are closely associated, but some others are not. Heart rate and blood 
pressure do not necessarily show parallelism with the carotid sinus reflex ; 
there are other factors influencing the control by the central nervous system, 
including impulses from the lower limbs, skin, abdominal viscera, etc., 
apparently independent of the buffer nerve mechanism. Afferent impulses 
from the vascular circuit in the lower limbs are important. Several postural 
vascular responses, absent while the trunk is horizontal, become operative 
when the upper end of the body is raised 30° or more from the horizontal 
plane. Great changes in blood pressure result from strong, extensive, 
tonic muscular contraction, as in standing with the knees bent, also during 
some dreams with emotional disturbance, sense of motor effort, night- 
mare, etc. 
Col. C. J. Bonn, C.M.G.—The ‘ Arneth’ count (4.15). 
In this communication evidence was presented to show that increase in 
the number of nucleus lobes in the polymorph leucocyte is dependent on 
the activity previously exercised, rather than on the age of the cell. This 
activity can be stimulated in various ways: (1) by incubating blood in a 
glass cell at body temperature ; (2) by allowing the leucocytes, so incubated, 
to return to the rounded-up resting condition ; and (3) by re-incubation of 
the same cell. Under such conditions it will be found that the cells in the 
incubated and re-incubated slides will show, on the average, a higher 
number of lobes per cell than the cells in the film obtained direct from the 
blood stream or in the resting condition. The living pus cell may be 
regarded as a cell which has exercised much activity. It has emigrated 
through the capillary wall, it has wandered through the tissues, or on to 
the surface of amucous membrane or wound. It may have ingested disease 
organisms or pigment particles such as carmine or indigo during incubation. 
It is, therefore, of interest to find that living active pus cells contain a larger 
number of lobes per cell than the white polymorph blood cells obtained 
from the blood stream of the same individual. 
The results of these incubation and feeding experiments were shown in 
graph form by charts illustrating the number of lobes in 100 cells in the 
case of blood films, incubated blood, resting cells, and re-incubated cells, 
from the same individual; also charts showing the relative increase in 
number of nuclei in pus cells, as against polymorphs from the blood stream, 
and also in cases of macrocytic or pernicious anemia. The suggestion was 
made that the increase in number of lobes per cell in the latter case was 
associated with the increased work and activity exercised by the smaller 
leucocyte and polymorph population in such cases. 
