ELECT 
decide - , in a pofitive maimer, whether the brain has any 
diieft influence on the heart, more particularly when they 
are repeated with the precautions which were taken by 
me, to coat fticc-effively, and alternately, the internal and 
external furfaces, and the fubftance even of the latter 
organ. In each of thefe experiments the natural difpoffi. 
tion was preferred between the different parts which ferve 
to unite the heart with the brain. 
“ 4. There is another mode of making the experiment, 
which confills, in the firft place, in detaching the heart 
from the bread. Secondly, in bringing it in contact with 
two different metals, at two points of its furface, or with 
portions of flefli coated with metals. And, thirdly, in 
eftablifhing a communication between the coatings, by 
means of a third metallic fubftance. In thefe cafes, Hum¬ 
boldt obferves that he has feen the movements produced. 
I muff confefs, notwithftanding, that although I have 
frequently repeated thefe experiments, with a ftridt ad¬ 
herence to the forms prefcribed, I could never perceive 
any fuch refult. 
“ I proceed now to experiments made on animals with 
red and warm blood. It became the more neceffary to 
try them, becaufe the mode of the contradtibility of ani¬ 
mals with red and cold blood, differs eflentially from that 
of animals with red and w - arm blood. 
“ 1. In the conrfe of the winter of the year 1798, I was 
authorized to make different experiments on the bodies 
of the unfortunate perfons who had been guillotined. 
Thefe bodies were brought to me about twenty minutes 
after the execution had taken place. In feveral of them 
the motive faculty was extinguished ; while, in others, I 
was enabled to excite it, with a greater or lefs degree of 
facility, in all the mufcles, by the ordinary methods which 
are reforted to on thefe occalions. It was more particu¬ 
larly manifefted in the mufcles of animal life, by means 
of the galvanic proceffes. I could never fucceed, how¬ 
ever, in the proaudtion of the fmallefl: movement, when 
I coated, either the fpinal marrow and the heart, ot the 
latter organ and the nerves it receives from the ganglions, 
by the great intercoftal, or from the brain, by the par 
vagum. Notv ithftanding this, when mechanical exciters 
were applied, in a diredt and immediate way, to the flefliy 
fibres, contractions enfued. Did this arife from the ner¬ 
vous filaments of the heart having been for home time in- 
fulated from the brain ? But, in fuch a cafe, why did thofe 
be'onging to the voluntary mufcles, which were likewife 
infulated, favour the production of the galvanic phe¬ 
nomena? The following experiments will clear up this 
doubt. 
“ 2. In experiments made on dogs and guinea-pigs, I 
coated, with two metallic fubftances, in the firft place, 
the brain and heart; next, the trunk of the fpinal mar¬ 
row and the latter organ ; and, finally, that organ and 
the nerve of the par vagum, from which it receives feve¬ 
ral nerves. The two coatings having been made to com¬ 
municate, there was not the fmallefl apparent refult : I 
could not perceive that the movements were re-produced, 
after they had ceafed; nor that they were accelerated 
during their continuance. 
“ 3i The cardiac nerves of two dogs having been coat¬ 
ed, both in their anterior and pofterior filaments, another 
coating was applied to the heart, fometimes at its ante¬ 
rior furface, and at others at its pofterior furface, and at 
others, again, at its fafciculi. The communication, as in 
the preceding experiment, did not produce any apparent 
movements. In experiments of this defcription, the com¬ 
munication ought not to be made until a certain portion 
of time has elapfed after the coating has been placed on 
the heart, to the end that what is merely the effect of 
metallic irritation, may not be afcribed to galvanifm. 
“ 4. Humboldt obferves, that when the heart is fud- 
denly. detached from the cavity of the pericardium, taking 
care that feveral of its infulated nerves fliould ftill re¬ 
main attached to the vifcus, contractions may be pro¬ 
duced by coating the latter with a metallic fubftance. 
R r C I T Y. $39 
and by touching the coating with another metal. I--tried 
this experiment repeatedly, but without fuccefs, except 
in one particular inftance, which was attended by feeble 
contractions. On the other hand, I fucceeded, almoft in¬ 
variably, in producing contractions in animals with red 
and warm blood, when I took out the heart, and brought 
it in contaCt, at two different points, with, metallic fub¬ 
ftances, between which a communication was eftablifhed. 
It appears to me that this is the only mode of producing 
on that organ, efficacioufly and demonftratively, the gal¬ 
vanic phenomena. It does not, however, prove what is 
the objeCt of my prefent refearches, namely, whether the 
brain has a direCt influence on the heart. If, indeed, we 
grant that the galvanic phenomena have, on thefe two 
kinds of mufcles, an equal influence, what is proved by 
this faCt ? Nothing more than that thefe phenomena are, 
in their fucceffion, governed by laws which are altoge¬ 
ther different from thofe of the phenomena of the nerves 
with which thefe mufcles correfpond.” 
Having difeuffed this important phy(iological queftion, 
M. Bichat proceeds to treat of the influence the deftruc- 
tion of the vital energy of the brain has on that of the 
refpeCtive organs, which he divides into thofe of animal 
life, and thofe of organic life. He enquires, irt the .firft 
place, whether the interruption of the organic functions, 
is a direCt effeCt of the ceffation of the cerebral action. 
After having proved, as he Jiad already done in the pre¬ 
ceding article, both by obferVation and experience, that 
all the internal functions are, in the fame way with the 
aCtion of the heart, withdrawn from the direCt afcendancy 
of the brain, and that, confequently, their interruption 
cannot be immediately derived from the deftruction of 
that organ ; and after having eftablifhed, anatomically 
and fubftantially, that the organic functions are not fub- 
jeCted to the immediate influence of the brain, feeing 
that the greater part of the vifeera by which thefe func¬ 
tions are performed, receive few, if any, of the vertebral 
nerves, but are rather fupplied with the nervous filaments 
arifing from the ganglions, fuch as are obferved in the 
liver, kidneys, pancreas, fpleen, intefiines, Sec. he de- 
monftrates the truth of the principle he has eftablifhed, 
by experiments on living animals. Thefe experiments 
were made on the ftomach, inteftines, bladder, uterus. 
See. of animals with warm blood, and were conftantly at¬ 
tended by a refult fimilar to the above. 1 They were after¬ 
wards repeated on cold-blooded animals; and juftified the 
general inference which he draws, namely, that “ with 
relation to the galvanic fluid, as well as in every other 
point of view, there is an enormous difference between 
the mufcles of animal life, and thofe of organic life.” 
The arrangement of galvanic combinations, its che¬ 
mical proceffes, and general laws, may be fummed up as 
follows: Two diflimilar metals, with an interpofed fluid 
or a (ingle metal, expofed to the aCtiou of two different 
fluids ; or any one of the conducting fubftances on which, 
unequal aClious can be induced by different fluids; con- 
ftitute a fimple galvanic combination. A feries of Inch 
combinations is denominated a galvanic battery. 
When two metals are employed, they produce site 
greateft effeCt, when the particular quality of one of them 
renders it extremely difficult of oxydation, while the other 
unites with oxygen with the greateft facility. If, upon 
a polifhed plate of fteel, water be laid, under the corn-' 
mon temperature of the atmofphere, in the conrfe of two, 
or three days the furface will be confiderubly oxydated. 
This is occafioned by the decompofition of the water. 
If, upon a ffmilarly moiftened furface of fteel a plate of 
zinc be placed, at the end of two or three days the fur¬ 
face of the fteel will be found covered with a white pow¬ 
der, which is the oxyd of zinc. When it is wiped off, 
the fteel will ftill polfefs its original polifh. This proves 
that the zinc unites more readily with oxygen than does 
the iron; but if a plate of filver be fubftituted to the zinc, 
then the fteel will be oxydaied. Confequently, filver is 
more difficult of oxydation than fteel, and fteel than zinc. 
Silver 
