THE MARCH OF MEDICINE—WINTROBE 383 
It had been known for more than 30 years that the pancreas was 
related to diabetes and a number of investigators had attempted with- 
out success to isolate the secretion of the cells contained in the islands 
of Langerhans. Banting was struck by the thought that by tying the 
pancreatic duct of animals it might be possible to obtain the secre- 
tion of the islet cells and that an extract of the cells might actually 
relieve the high blood sugar found in diabetes. He was so obsessed 
with the idea that he got up at 2 in the morning and wrote three sen- 
tences in his notebook. “Ligate pancreatic duct of dogs. Wait 6 to 
8 weeks for degeneration. Remove the residue and extract.” 
It is significant that when he went to Toronto to talk to the 
professor of physiology there, Dr. J. J. R. MacLeod, he got little 
encouragement. Some years later this same MacLeod, together with 
Banting, received the Nobel Prize for Banting’s great discovery. For- 
tunately, Banting’s determination won out and with the aid of a medi- 
cal student, Charles H. Best, he succeeded in making an extract of the 
islets as he proposed. Banting and Best operated on the first dog 
on May 16, 1921. By January 1923 insulin was being successfully 
used in the treatment of human diabetes in a number of clinics in 
Canada and the United States. 
The discovery of the treatment of diabetes is closely linked with 
that for pernicious anemia, for George R. Minot, who is mainly 
responsible for the latter, himself was suffering from diabetes and 
might not have lived to make his important studies in pernicious 
anemia. This disease was so called because until 1926 it inevitably 
led to death. The story of Minot’s success is one of painstaking 
study, patient observation, and persistent effort in the face of personal 
ill health as well as frank skepticism and even open criticism from 
his colleagues. It was naturally not easy to accept the idea that a pale, 
exhausted-looking patient must consume a half pound of liver daily 
and could expect to get better thereby. It was indeed a great surprise 
to discover that after only a few days of liver therapy such a patient 
craved food, color appeared in his face, and his outlook had changed. 
The development of an extract of liver which is so potent that one in- 
jection per month or less often is sufficient to maintain such a patient 
in normal condition is the natural outcome of the researches which 
Minot’s perseverance initiated. 
The story of the vitamins is another impressive chapter in the 
history of medical science. Deficiency diseases have been known for 
a long time. Scurvy hampered the crusaders and ravaged the sailors 
of Vasco da Gama and of Cartier. It came to be known as “the plague 
of the sea and the spoyle of the mariners.” The Spaniards and the 
Italians knew pellagra and recognized that it was associated with the 
eating of unsuitable food. Glisson described rickets, which term is 
