An old Scotch physician, for whom I had a great respect, and whom I frequently met professionally in the city, used to say, as we were entering the patient's room together, 'Weel, Mister Cooper, we ha' only twa things to keep in meend, and they'll searve us for here and herea'ter; one is always to have the fear of the Laird before our ees; that 'ill do for herea'ter; and t'other is to keep your booels open, and that will do for here.'

Having made a sufficient opening to admit my finger into the abdomen, I passed it between the intestines to the spine, and felt the aorta greatly enlarged, and beating with excessive force. By means of my finger nail, I scratched through the peritoneum on the left side of the aorta, and then gradually passed my finger between the aorta and the spine, and again penetrated the peritoneum, on the right side of the aorta. I had now my finger under the artery, and by its side I conveyed the blunt aneurismal needle, armed with a single ligature behind it...
Describing the first ligation of the aorta in 1817 for left femoral aneurysm.

I have made many mistakes myself; in learning the anatomy of the eye I dare say, I have spoiled a hatfull; the best surgeon, like the best general, is he who makes the fewest mistakes.

If you are too fond of new remedies, first you will not cure your patients; secondly, you will have no patients to cure.

In the collecting of evidence upon any medical subject, there are but three sources from which we can hope to obtain it: viz. from observation of the living subject; from examination of the dead; and from experiments upon living animals.

In the performance of our duty one feeling should direct us; the case we should consider as our own, and we should ask ourselves, whether, placed under similar circumstances, we should choose to submit to the pain and danger we are about to inflict.

It is the surgeon’s duty to tranquillize the temper, to beget cheerfulness, and to impart confidence of recovery.

My lectures were highly esteemed, but I am of opinion my operations rather kept down my practice, than increased it.

Nothing is known in our profession by guess; and I do not believe, that from the first dawn of medical science to the present moment, a single correct idea has ever emanated from conjecture: it is right therefore, that those who are studying their profession should be aware that there is no short road to knowledge; and that observation on the diseased living, examination of the dead, and experiments upon living animals, are the only sources of true knowledge; and that inductions from these are the sole bases of legitimate theory.

On the whole, more harm than good is done by medication.

The means by which I preserve my own health are, temperance, early rising, and spunging the body every morning with cold water, a practice I have pursued for thirty years ; and though I go from this heated theatre into the squares of the Hospital, in the severest winter nights, with merely silk stockings on my legs, yet I scarcely ever have a cold...

The science of medicine is founded on conjecture, and improved by murder.
[Lamenting the deadly consequences of blind ignorance in medical treatments.]

Before his [Sir Astley Cooper’s] time, operations were too often frightful alternatives or hazardous compromises; and they were not seldom considered rather as the resource of despair than as a means of remedy; he always made them follow, as it were, in the natural course of treatment; he gave them a scientific character; and he moreover, succeeded, in a great degree, in divesting them of their terrors, by performing them unostentatiously, simply, confidently, and cheerfully, and thereby inspiring the patient with hope of relief, where previously resignation under misfortune had too often been all that could be expected from the sufferer.