This willingness to risk the last hours of life, which the Talmud in Avodah Zarah mentions as a regular rule, was applied practically in at least two instances in the responsa literature. Jacob Reischer of Metz d. 1733) in his Shevut Yaakov, 111,#75, had exactly such a question. The person was, in the doctor’s judgment, now dying. He had only one or two days to live. There was, however, a new medicine that could perhaps cure him, enabling him to live for a long time, but it might also kill him. Reischer , according to the principles mentioned above, said that while we may not in general hasten death, if however the doctors agree that there is a fair chance that he may be cured for a good extension of his life, then we should risk this last day of his life. Precisely the same question has come up recently in a responsum by Jacob Breisch of Zurich , Switzerland , in his newly appeared volume III, responsum#141. He comes to the same conclusion as did Jacob Reischer two centuries before.
The principle, therefore, is clear enough. These last few hours
of life, hayei shaah, are not so important in the ethics of the halakhah that we may keep on preventing a person from dying, just in order to gain another hour or two. Of course, for a fair probability of cure, we must try all means and methods and even risk for a probable cure wiping out of his last hour or two.
Greater knowledge of the human body enables us to define much more closely than the rabbis of the past did when a person is actually moribund or whether he still has viability. We also have new remedies such as heart-pacers, adrenalin, etc. Nevertheless, the ethical principle underlying the Jewish tradition seems strong, although, of course, applied somewhat differently today. The ethics of the law would be substantially as follows: If the modern methods of revival bring with them a fair probability that the patient may recover some health for, let us say, twelve months(as their old test had it) and be fairly free of pain