In 1857 the operation of cesarean section (that is, delivery of a baby through an abdominal incision) was generally looked upon as a procedure of last resort to be undertaken rarely and only when other measures were inappropriate or had failed. Although many such operations were performed in the major European centers, especially Paris, the maternal and fetal death rates were extremely high. Most American doctors considered the cesarean to be unduly hazardous and seldom, if ever, justified. Thus there were few reports of maternal survival after cesarean section in the American literature, and no case had been reported from the Far West. However, Cooper let it be known in conversation with Dr. Wooster and others that while in practice in Peoria he had performed a cesarean with success to both mother and child. The mother was a German woman who was still living in Illinois.   He was soon to have occasion to perform the procedure again in what proved to be the first successful cesarean section on the Pacific Coast. The circumstances that led him to the fateful decision to operate were these.
Dr. Martha Thurston, graduate of the New England Female Medical College in Boston, and certainly one of the earliest women to practice in San Francisco, had frequently consulted Cooper in whom she had great confidence. In December 1856 she sought has advice about a particularly delicate problem. The patient was Mrs. Mary Hodges, a thirty-five year-old school teacher, whose recent marriage had not been consummated because her vaginal orifice was firmly occluded except for an opening "the size of a quill." With Dr. Thurston as his assistant, Cooper operated on Mrs. Hodges and relieved the obstruction by removing considerable tissue "of ligamentous hardness," which was followed by two weeks of packing for dilatation. Cooper warned Mrs. Hodges that she would be uncomfortable after the operation. Nevertheless, during the early postoperative period a friend invited her and her husband to a party. which the poor woman attended and, so that no one would know or suspect that she had had an operation, danced the whole night until she fainted away in the arms of her husband. In his notes Cooper describes the operative findings and procedure in such a manner as to indicate that residual thickening or fibrosis in Mrs. Hodges' vaginal wall might later cause obstruction to normal obstetrical delivery. 
In view of the possibility of persistent narrowing of the vaginal canal, Dr. Thurston advised Mrs. Hodges against having children. It was therefore with some apprehension that Drs. Thurston and Cooper learned a few months after the operation that Mrs. Hodges was pregnant. Following a period of despondency and desire to have an abortion, Mrs. Hodges was reconciled to having a baby and returned to see Dr. Cooper who advised that she might have difficulty delivering a full-term infant and should have her delivery at seven months when the baby was small. After discussing the matter with her husband, who was fearful that early delivery might harm the baby, Mrs. Hodges returned to say that she was determined that the pregnancy should go to full term, and that Dr. Cooper should attend her at her confinement - there being no one else whom she could trust.
Mrs. Catherine Roper, Matron at Dr. Cooper's Pacific Clinical Infirmary, recalled the following exchanges which then took place between the Doctor and Mrs. Hodges: 
[Mrs. Hodges] was but just well from the first operation [for vaginal occlusion], when she came [to Dr. Cooper] and said that she was pregnant. She said she knew she could not be delivered without an important operation. She asked the Doctor if he would attend her at her confinement. The Doctor told her that that was impossible. He said: "Mrs. Hodges, the condition of my health is such - I have a paralysis in my head and face - and if I lose a night's rest, I have to keep my bed for some time, and cannot attend to my patients in the institution." He said: "I would not be justified in taking that kind of practice." She appeared to be even much distressed when the Doctor told her this. She said she had so much confidence in the Doctor's skill that she did not know what she would do if he did not take her. She said that there was not a man on this coast that she had the confidence, as a medical man and a surgeon, that she had in him. The Doctor said: "There are many skillful accoucheurs in this city," and the Doctor mentioned the names of many persons - half a dozen or more - whom he could and would recommend. She did not say whether she would take one of them or not. She seemed to be very much discouraged. She said she would tell her husband what the Doctor had said. The Doctor told her again that he could not possibly attend her. He said that if he lost a night's rest there was a spasm came over him. He said that he was afraid of the effects of his disease, if he did not take care of himself. She then said: "Certainly, I would not desire you under such circumstances." She said: "I will tell my husband what you have said, Dr." The next time I saw her, she said that her husband was very much disappointed... She said that she had told her husband, and that he was very much disappointed, and she said she wanted to know if the Doctor would promise not to leave the city, if she would let him know when she was taken with labor. The Doctor promised her that he would [not leave]. "Let me understand you rightly," she said - I give you her exact language now - "Let me understand you rightly; if it is necessary that an operation should be performed, you will come and perform it?" "I will," he says....
She said - and I give you her language - "I am as confident that there will have to be an operation performed, before I am delivered, as I am that I have got to die before I go to heaven" - that's exactly what she said....
She came again [to the Infirmary], and I had an interview with the Doctor, and he told her that he would advise her to have her labor brought on in seven months. He thought that a small child could be born alive, but that a large child could not. I told her she had better take the Doctor's advice, and have labor in seven months. She said that her husband was so anxious for the child that she did not know what to do - she would consult him. She came back again and said that her husband was anxious for her to go the full time [full term] and have the child. She said she was afraid, but she said that she felt that she was almost willing to be sacrificed if the child could be born alive....
[She came again] . . . about a week before the day on which I heard that she was [in labor] . . . "Well," she said, "if I could only have had you Dr. Cooper, I do believe I should be reconciled - I think I dream of it. It appears to me now, that if you would only say that you would come to me when I am taken in labor I would be reconciled and delivered." The Doctor told her that it was impossible for him to lose a night's rest. She said: "I know my age is against me, and that I must expect considerable suffering." She said, too: "Maybe you would not lose a night's rest." The Doctor said: "Mrs. Hodges, I cannot take your case. I have constantly to send such cases as yours to others." She seemed to me as though determined to make the Doctor take the case. The Doctor repeatedly told her that there were plenty of very skillful medical men, who would come and do as well for her, as an accoucheur, as he would....
When the Doctor said that, she said: "I doubt it." Finally she said: "Well, then, Doctor, this is the last time I expect to see you before [I go into labor]. Now, you promise me here, before Mrs. Roper, that you will not leave town, till you hear from me." Then she turned to me and said: "You will keep reminding the Doctor of his promise to me, not to leave the city, wont you, Mrs. Roper?" I said: "Don't be alarmed, Mrs. Hodges; I will remind the Doctor every morning." I knew that as he had so many patients and so much on his mind, the promise might slip, if it was not recalled. She said that she would depend upon me to keep fresh the Doctor's memory. The Doctor recommended a number of physicians - Dr. Rowell, Dr. Williamson, Dr. Sheldon and some others, whose names I do not now recollect.
Dr. Cooper next heard from Mrs. Hodges early on the morning of 8 November 1857. Now at full term, she informed him by messenger that she was in labor and wished to see him. When he arrived he found that she had not engaged an accoucheur as he had advised and that she wished him to take the responsibility for her delivery. Whatever Cooper's thoughts might have been at this turn of events, he agreed to be of assistance. As he had previously made clear, he would not manage her labor. Nevertheless, he set out to find someone who would attend upon her. According to his notes, he made the following arrangement: 
I then called upon Dr. Wooster, a medical man of more than ordinary medical reading, but a comparative stranger with a family and whom I was endeavoring to introduce into family practice. I requested him to take charge of the case at the same time giving him a history of the lady's pelvic examination and previous operation and expressed my apprehensions in regard to the possibility of delivery in the natural way. . . I advised him to wait patiently and let nature do her best seeing that the obstruction in the soft parts might yield to long continued pressure but at the same time stated by way of encouragement to him, as he appeared to falter slightly in view of the impending difficulties, that if it came to extreme measures not to fear the responsibility as I should be unwilling to place it upon him in that case and to send for me at any time when he gave up all hope of a natural delivery. I promised to call occasionally in the meantime which I did.
On the evening of November the 10th at 7, while Dr Cooper was having supper in the dining room at the Pacific Clinical Infirmary, Mr. Hodges came with a note from Dr. Wooster desiring Dr. Cooper to come in great haste, and requesting him to bring instruments as Mrs. Hodges was rapidly sinking. The Doctor left immediately with Mr. Hodges without finishing his meal.
On arrival at the Hodges' residence Cooper went at once to the small upstairs bedroom and examined the patient. She had then been in labor for sixty hours and now lay moaning, and semiconscious from intermittent inhalation of chloroform. Dr. Wooster reported that he had given her the maximum amount of ergot to stimulate uterine contractions. In spite of the ergot and prolonged labor, the head was tightly lodged at the vaginal level (in a rare occipito-posterior position), the baby was dead and the patient was exhausted. In this situation, the strongly-favored obstetrical approach would be to deliver the baby per vaginam by forceps. It might be necessary also to reduce the size of the head by opening the cranium with a hook-like instrument known as a "crotchet" and removing the cranial contents. Another possible option was to dismember the infant. When Cooper decided not to use these conventional measures but to resort to the drastic cesarean section instead, his judgement and motives were questioned and he was sued for malpractice by Mr. and Mrs. Hodges. In his personal notes on the case, he cited the following exceptional circumstances as justification for his decision to perform the controversial operation: 
Owing to the almost unparalleled rigidity of the vagina, I entertained most serious apprehensions that neither the forceps nor the crotchet could be used and was confirmed in that opinion on my arrival.
A portion of the scalp the diameter of nearly a dollar could be distinctly felt but it was utterly impossible to introduce the end of the finger between it and the walls of the vagina and no one could possibly form any opinion of the presentation. All parts of the vagina were equally unyielding so that it was plain to perceive that neither the forceps nor the crotchet could be used without first cutting through the walls of the vagina both posteriorly and anteriorly for the space of from one and a half to three inches and with very uncertain prospect of success (but with very real prospect of serious consequences such as producing a fistula between bladder or rectum and the vagina). To this I preferred the caesarean section and this operation appeared to become the more imperatively demanded since we had diagnosticated twins and Dr. Wooster assured me that a few minutes previously to my arrival he had distinctly heard the pulsation of the fetal heart.
I was (also) led to mistake the case for one of twins in consequence of Dr. Wooster permitting the urine to accumulate to the amount of more than a gallon while he assured me that it had been drawn a few moments prior to my arrival. The bladder had attained almost the hardness of a child and the major portion of the child being high up in the abdomen a deep depression was formed between the prominence formed by the bladder below and the child above.
I think we might possibly have tried the crotchet but for this mistake. We might have done so to have said that we tried the crotchet first as a matter of self protection against the accusations of a combination of medical men in this city who with a zeal and industry worthy of better causes had pursued and thrown obstacles in my professional path ever since my arrival in this city.
But under the impression that there were twins and one of these alive a moment before and possibly then in a state of suspended animation, I forget to think of the means of protecting my own reputation in view of my duty to the patient.
I considered it utterly impossible to dissect one child and bring it away without cutting or lacerating the woman and of course a second (child) would be (injured) much worse.
Dr. Wooster opposed the caesarian section at first while he admitted the impossibility of extracting two children through that passage and have the patient survive and said in the most emphatic manner that it would be better to let the woman die than for us to perform the caesarian section with the (small) chance of recovery and run the risks of censure should she die, referring at the same time to the combination of malignant medical men who he said "are always like a pack of bloodhounds on your track," or words to that effect.
He appeared alarmed beyond anything I had met with in view of the immense responsibility I had been the unintentional means of throwing upon him and from that moment I conceived a feeling of contempt for him which never could have been removed even had he remained my friend and an honorable man as I supposed him then to be.
Our consultation was hastily dissolved when I assured him that if that was the only reason why we should not operate I was going to proceed at once and thereby give this woman what I considered the only remaining chance of recovery and take all responsibility let the case result as it may.
Whereupon he agreed to the operation then and said, "I will defend it from the obloquy of the curious and the reprobation of the ignorant to the best of my poor ability."
The Operation, 10 November 1857
Cooper's decision to operate without delay was ultimately based on the diagnosis of twins which in turn rested on two critical observations. Although he and Wooster agreed that the baby in the birth canal was dead, Wooster was sure that he had heard the beating of a second fetal heart only moment's before Cooper's arrival. Furthermore, the patient's abdomen was markedly distended, far beyond that consistent with a single pregnancy, and Wooster assured him that he had emptied the bladder with a catheter only shortly before. At the time Cooper said, "If there are not twins, I don't know how to account for the shape of the abdomen." If twins were indeed present, the life of the second one could only be saved by prompt action such as an experienced and confident surgeon could take.    
The setting for the operation was stark. It was 10 P.M. and several candles shed an uncertain light on the bed where lay the restless and semi-stuperous patient. Preparation by Cooper and Wooster consisted of taking off their coats, rolling up their sleeves and laying out a few instruments from the small case Cooper always carried with him. The only other person present was Mrs. Kriemer, the grocer's wife who had ministered to Mrs. Hodges since her labor began. She was so aghast at the thought of an operation that she agreed to stay only if she might sit in a corner of the room and shut her eyes.
The surgeons faced each other across the bed for a few tense moments awaiting the deep narcosis of chloroform and then, said Wooster, "We operated, he using the knife." At the first stroke of the blade in making the incision a stream of fluid under pressure shot out eight or ten feet across the room striking Cooper in the face, blinding him, and forcing him to lay down the knife to wipe his eyes. Said he:
A considerable amount of fluid spouted out striking me about the mouth and nostrils imparting at once the taste and smell of urine. This surprised me very much and I hastened to finish the incision through the abdominal wall which being done, the bladder was exposed to view distended to its utmost capacity. Dr. Wooster now confessed having deceived me in regard to the condition of the bladder, said he had twice tried to introduce the catheter but could not and was ashamed to acknowledge to me that he failed in so simple an operation. I therefore concluded there must be some slight rent at that point in the bladder through which urine that I tasted had passed and might still escape slowly into the abdominal cavity so without losing any time I punctured the bladder at the usual point above the pubis and discharged the major portion of its contents by inclining its fundus forward over the loins after which the uterus was incised and the child extracted.
There was only one baby, weighing a hefty eleven and a half pounds, its head and face badly misshapen from being tightly impacted in the lower strait. The patient's unduly enlarged abdomen was caused by a bladder distended with several quarts of urine. So much for the diagnosis of twins. During the operation hemorrhage was profuse and the patient stopped breathing repeatedly, requiring heroic feats of hemostasis and resuscitation, problems Cooper managed with cool efficiency - and also requiring better light provided by the horrified Mrs. Kriemer who was routed from her corner to hold a candle over the bloody field. Innovative as always, Cooper defied contemporary obstetrical authorities by closing the uterus with sutures to control bleeding, citing as his reason the high incidence of post-cesarean death from hemorrhage following non-suture of the uterus.
Cooper summarized the postoperative course in a few words:
The patient remained feeble for many days but finally recovered rapidly and in three months was able to walk with ease from her residence north of Greenwich to Pacific Clinical Infirmary on Mission near 3rd, a distance of near two miles which she did of mornings occasionally before nine o'clock when she was engaged in teaching school. The puncture in the bladder as might be expected healed at once and gave not the least inconvenience.
During the postoperative period, Wooster and Cooper followed Mrs. Hodges together. Wooster was particularly attentive, taking great pride in her progress. Never once did Cooper bring up with him the subject of the misdiagnosis of twins and the reasons for it. On the contrary, he encouraged the continuance of the cordial relations they had enjoyed prior to the operation. During the several months of their joint attendance on the convalescing Mrs. Hodges they were on the best of terms. It was Wooster's ambition to found a medical journal and Cooper agreed to finance the venture.
The cesarean operation, being the first successful procedure of its kind in the city, was much discussed among the local profession. Although some were critical, the early reaction seemed generally favorable. Wooster relished having participated in the case and during the months of November and December 1857 stated frequently to physicians that "I and Dr. Cooper performed the operation;" that "it was advisable and necessary to perform it and that it was successful and a great triumph of surgery," or words to that effect.