262 Mr. J. J. Woodward on the Modern 
were accompanied by a fall of the curve, which he regarded 
as proof that more blood goes to the brain and less to the arm 
during emotion, or mental action, than at other times. But 
the following year these observations were repeated with great 
care, and with an improved plethysmograph, by Basch, of 
Vienna*, who failed to verify them. Most of the phlegmatic 
Germans on whom he experimented did sums in their heads, 
and otherwise exerted their minds, without producing the 
slightest modification of the curve; and none of them appear 
to have been as emotional as Dr. Pagliani, of whom Mosso 
relates that, his arm being in the plethysmograph, when the 
revered Prof. Ludwig entered the room the curve fell as if he 
had received an electric shock. Basch has cautiously investi- 
gated the causes of the varying quantity of blood in the arm 
in these experiments, and has clearly shown how many 
general and local conditions concur in producing the result. 
Hspecially has he emphasized the effect of variations in the 
abdominal circulation, which appear to exercise a much more 
considerable influence upon the size of the arm than any 
changes that occur in the brain. 
In subsequent works Mosso has stated that during mental 
effort, such, for example, as is required to multiply small 
numbers in the head, the radial pulse, as recorded by the 
sphygmograph, is shown to become somewhat more frequent, 
and the recerding lever does not rise so high as at other 
times}. Thanhoffer, who has pointed out that in these ob- 
servations the influence of respiration on the pulse was neg- 
lected, concluded, nevertheless, from his own sphygmographie 
observations, that after due allowance is made for this com- 
plicating influence, it must be conceded that cerebral activity 
does exercise a certain effect upon the pulse, and in the direc- 
tion statedt{. Kugéne Gley, in a recently published essay, 
claims to have obtained similar results, and states that at the 
same time the sphygmographic trace of the carotid artery 
shows a higher upstroke of the recording lever, and other 
indications of dilatation of the vessel§. While these observa- 
* Basch, “ Die volumetrische Bestimmung des Blutdrucks am Men- 
schen,” Stricker’s Med. Jahrb. 1876, 8. 431. See also Rollet, in Her- 
mann’s Handb. der Phys. Bd. iv. Th. 1 (Leipsic, 1880), 8. 306. 
+ Mosso, ‘‘ Die Diagnostic des Pulses in Bezug auf die localen Verin- 
derungen desselben,” Leipsic, 1879; also by the same, “Sulla circola- 
zione del sangue nel cervello dell’ uomo,” Rome, 1880. 
{ Thanhofter, ‘“ Der Einfluss der Gehirnthatigkeit auf den Puls,” Pfii- 
ger’s Archiv, Bd. xix. 1879, S. 254. 
§ Eugéne Gley, “ Essai critique sur les conditions physiologiques de la 
pensée. Etat du pouls carotidien pendant le travail intellectuel,’ Ar- 
chives de Phys. norm. et path., Sept.-Oct. 1881, p. 741. 
