100 REPORT OF NATIONAL MUSEUM, 1921. 
Next in importance is the accession covering the contribution of 
the H. K. Mulford Co., of Philadelphia, Pa., illustrating vaccine and 
serum therapy. Few of the present generation are aware of the fact 
that smallpox, the most terrible of all the ministers of death, killed 
at least 60,000,000 people in the 18th century, and that in preceding 
centuries, about 10 per cent of all deaths were attributable to this dis- 
ease. Millions of the survivors weakened, crippled, sightless, all bore 
hideous traces of the power of this scourge. It was left for a humble 
village doctor, Edward Jenner, in 1789 to conquer this disease by a 
bit of virus on the point of an ivory lancet. It was he who dem- 
onstrated to the world that this disease in the cow is mild, while in 
man it is virulent, and introduced cowpox virus into the system of 
human subjects to render them immune from the malignant type. 
With compulsory vaccination, Jenner’s discovery has become so effec- 
tive that many active physicians have never seen a case of smallpox. 
The average person knows comparatively little about this wonderful 
discovery and the manner in which one of the greatest scourges to 
mankind was conquered. An exhibit has been arranged in a manner 
which tells something of the history of the discovery; the terrible 
effects of the disease; the trifling inconvenience of vaccination; and 
the modern sanitary methods of procuring the virus, etc. 
Another valuable medical discovery was that of the antitoxic 
property of the blood serum of animals immunized by the inocula- 
tion of bacterial toxins. The principle of this discovery, which was 
made in 1890 by Behring and Kitasato, is that the blood serum of a 
subject which has recovered from an attack of a communicable dis- 
ease caused by bacteria when transferred to another subject will 
render the latter immune. Since this discovery, antitoxins for the 
prophylactic and curative treatment of diphtheria and lockjaw have 
been included in the United States Pharmacopoeia. All serums are 
obtained in practically the same manner, and so an educational ex- 
hibit was arranged to give the public a better understanding of the 
theory and principles of serum therapy. The subject of diphtheria 
was chosen to illustrate in detail, and there follows exhibits relating 
to lockjaw, pneumonia, and cerebrospinal meningitis. By means of 
charts, photographs, and specimens Museum visitors are shown how 
the bacteria which cause these diseases are grown in Loefller’s blood 
serum; the manner of injecting these organisms into horses; how the 
immunized horses are bled; steps in obtaining the blood serum; tests 
for purity with filled syringes ready for administration; and mor- 
tality tables showing the decrease in fatalities from these diseases 
since this discovery. 
That hay fever is the result of pollen irritation is now an accepted 
fact, and the protein sensitization theory has received a great deal 
