VI
It is necessary for the heart, as for all muscles, to be fed. For it, indeed, this need is more imperative, as it may not stand still in order to rest when it is tired. The continuous work to which it is condemned explains to us how every alteration in the composition and amount of blood is immediately manifested by changing its nutrition and consequently its strength. Knowing that the heart is in constant contact with the blood, that is, with the nutriment distributed by it to all parts of the body, one might think that it could in this way take the best part for itself, as it helps itself at first hand; at the least, that it would take a more abundant portion than the other organs, or that nature allowed it to satisfy its appetite unreservedly. But this is not the case. In our body the rations of all organs are calculated and distributed according to the need of each. There is also a very strict economy of nutrition observed, because when any part of the body works more than usual, its increased needs are supplied by diminishing the rations of the other organs. The vaso-motor nerves are charged with this distribution of victuals, if I may so express myself. The heart, like all other muscles, takes as much blood as it needs for its maintenance out of its cavity by means of the coronary arteries branching off from the aorta. There is a control exercised over the heart also, and the vaso-motor nerves could, if it were absolutely necessary, diminish its rations and leave it barely sufficient strength to distribute the food to all the other parts of the body.
Physiologists have endeavoured in vain during the last centuries to find in the greater or lesser nutrition of the cardiac muscle the cause of its more or less accelerated movements. One of the most daring theories was propounded by Giovanni Lancisi, the celebrated Roman court-physician, one of the most illustrious physiologists Italy has ever possessed.
In his book 'De motu cordis,’ printed in the year 1728 by the Roman University Press, he develops a theory so manifestly materialistic of the origin of the pulsation of the heart during emotion and mental suffering, that it seems almost impossible the book should have been dedicated to the memory of Clement XI. and printed with the pontifical types, by permission of the Sacred College. The Roman curia did not foresee that those first steps would lead physiology so far away from their dogmas, and did not suspect that such simple notions about the functions of the human machine were pregnant with the innovative germs of modern philosophy, since it allowed its great physician to speak freely, and since it furnished him with the means for his physiological investigations, heaped honours upon him, and handed down splendid editions of his immortal books to posterity.
Mental functions are placed by Lancisi in close dependence on the nerves, the ganglia, and the coronary vessels of the heart. The material organs it is which influence mental movements. The heat of passion, the storm of emotions, have in the heart mechanisms by which they may be moderated and regulated. It is as though the nerves and ganglia of the heart, by driving the blood with more or less violence into the brain, could excite the instincts; as though the character and disposition of the mind depended on the material structure and the physical modifications of the body.
CHAPTER VII
RESPIRATION AND OPPRESSION