Even this brief review of the careers and the writings of the physicians of early Christian times shows how well the tradition of old Greek medicine was being carried on. There was much to hamper the cultivation of science in the disturbances of the time, the gradual breaking up of the Roman Empire, and the replacement of the peoples of southern Europe by the northern nations, who had come in, yet in spite of all this, medical tradition was well preserved. The most prominent of the conservators were themselves men whose opinions on problems of practical medicine were often of value, and whose powers of observation frequently cannot but be admired. There is absolutely no trace of anything like opposition to the development of medical science or medical practice, but, on the contrary, everywhere among political and ecclesiastical authorities, we find encouragement and patronage. The very fact that, in the storm and stress of the succeeding centuries, manuscript copies of the writings of the physicians of this time were preserved for us in spite of the many vicissitudes to which they were subjected from fire, and war, and accidents of various kinds for hundreds of years, until the coming of printing, shows in what estimation they were held. During this time they owed their preservation to churchmen, for the libraries and the copying-rooms were all under ecclesiastical control. III GREAT JEWISH PHYSICIANS[3] Any account of Old-Time Makers of Medicine without a chapter on the Jewish Physicians would indeed be incomplete. They are among the most important factors in medieval medicine, representing one of the most significant elements of medical progress. In spite of the disadvantages under which their race labored because of the popular feeling against them on the part of the Christians in the earlier centuries and of the Mohammedans later, men of genius from the race succeeded in making their influence felt not only on their own times, but accomplished so much in making and writing medicine as to influence many subsequent generations. Living the segregated life that as a rule they had to, from the earliest times (the Ghettos have only disappeared in the nineteenth century), it would seem almost impossible for them to have done great intellectual work. It is one of the very common illusions, however, that great intellectual work is accomplished mainly in the midst of comfortable circumstances and as the result of encouraging conditions. Most of our great makers of medicine at all times, and never more so than during the past century, have been the sons of the poor, who have had to earn their own living, as a rule, before they reached manhood, and who have always had the spur of that necessity which has been so well called the mother of invention. Their hard living conditions probably rather favored than hampered their intellectual accomplishments.