In my opinion he may operate with much more solid probability than that which exists in Case II. If the argument is more for the death of the foetus than for its life, this, of course, strengthens the permissibility of the operation. (1) The danger to the mother is exactly the same,_caeteris paribus_, as in Case II.; (2) the foetus is only probably alive. An actual danger to life is opposed to the probable life of a materially unjust aggressor; therefore the surgeon may probably operate at once. Probable here is used in the technical sense of the term. Case IV. The following case is given because a similar one was proposed in the articles in the _American Ecclesiastical Review_, but it is not a practical case. The surgeon, after consultation, does not know whether the growth in a woman's pelvis is a malignant tumour or a sac containing an extrauterine foetus. If the growth is a malignant tumour, the woman is in actual and certain danger of life, her death is a mere matter of time if a malignant tumour is not removed, and the sooner the tumour is removed the better. If operation is deferred, metastases of the tumour will have occurred, and operation will be too late. The indication when we find a malignant tumour is, if it is not already too late to operate, to take it out at once. If the surgeon thinks that the growth may possibly be a foetus, and he puts off the operation until a time when certain signs of pregnancy should be present to establish a diagnosis of gestation, or their lack to establish a diagnosis of tumour, it would almost surely be too late to operate in the event the growth turned out to be a malignant tumour. As has been said, the case is not practical, because malignant tumours of the tube are so very rare that they are not to be looked for,--only one or two have been observed. {36} Malignant tumours about the tube should be diagnosed. Supposing, however, the case to stand, it offers in favour of operation a probabilism stronger than that in any case except Case I., because the mother's danger is graver, and the argument concerning the foetus is the same as that in Case III. Case V. Suppose a doubtful case like Case III. or Case IV., but after the surgeon has opened the abdomen he finds a foetus evidently alive. This is an improbable but a possible case. Case V. then becomes like Case II. with the addition of another grave danger to the lives of both the mother and the foetus, which is the coeliotomy already performed. The suggestion that the surgeon can leave the woman, back out of the case, is absurd. If he closes the abdomen, the coeliotomy may cause tubal abortion, the wound might have to be opened again in a few hours or a few days, and the mother would be left in much greater peril than she was in Case II. For the reasons already given, he should go on with the operation.