THE MARCH OF MEDICINE—WINTROBE 38) 
hemorrhagic state. The chemical structure of many of these sub- 
stances has been discovered. Great strides have been made in under- 
standing their mode of action. This has meant learning in detail 
about the finer chemical processes on which life and growth depend. 
It has been demonstrated, too, that various species of animals 
differ in their needs for the different vitamins and that the manifes- 
tations of deficiency are not always the same in all animals. As far 
as man is concerned we have already learned about the dramatic effect 
of niacin in pellagra and the importance of vitamin K in certain types 
of hemorrhage, while man’s need for vitamin C and vitamin D are 
by now old established facts. But there is a great deal with reference 
to man which is still unknown, a fact which those seeking financial 
gain by the sale of vitamins choose to ignore. Much has been claimed 
for which there is no adequate scientific basis. In no field has the 
public been given so distorted a picture as in that of the vitamins. 
THE PRESENT-DAY “WONDER DRUGS” 
When the present era of medicine will be history, it will probably 
be called the “Therapeutic Period.” As one scans the development 
of medical knowledge since the Renaissance, three earlier periods 
can be made out. The first is the Anatomical, when students of medi- 
cine sought to learn about the structure of the human body. As this 
knowledge was gained, curiosity was aroused as to the manner in which 
these organs function—the Physiological Period. The study of the 
structural abnormalities produced by disease was closely correlated 
with a search for the causes of disease and the study of the mecha- 
nisms whereby disease is produced. This may be designated as the 
Ktiological Period. Obviously these periods are not sharply sepa- 
rated from one another nor can the study of structure, function, causes, 
and mechanisms be regarded as now completed. These divisions fol- 
low one another naturally, however, and the knowledge so gained is 
a necessary prerequisite to the development of intelligent and effective 
methods of treatment. 
The fantastic methods of treatment which were practiced in the 
earlier days of medicine, like the criminal hokus pokus of the char- 
latans and quacks of today, were founded in ignorance and flourished 
thereby. The advances in our knowledge in the last 75 years have 
been so great that it has been possible to devise for certain diseases 
specific methods of treatment, and to apply such methods with under- 
standing. The advances in surgery have been described already; the 
development of antitoxins, serums, and vaccines has been mentioned, 
and the discovery of such substances as insulin, liver extract, and the 
vitamins has been discussed. The most dramatic advances of all have 
been made in the field of chemotherapy, by which is meant the treat- 
ment of disease by specific drugs. 
