PENICILLIN—-FLOREY AND CHAIN 465 
before it reached the intestine. It does not pass from the blood into 
the cerebrospinal fluid. Penicillin was shown to be rapidly excreted 
in the urine, the bile, and to some extent in the saliva of animals. In 
man also, excretion in the urine is very rapid, and this explains why 
the doses have to be not only large but frequent. To keep a high con- 
centration of penicillin in the blood is like filling a bathtub with the 
plug out. 
Another important observation was that the antibacterial action of 
penicillin is not diminished in the presence of blood, pus, and tissue 
constituents. This is in sharp contrast to the sulfonamide group of 
drugs, whose activity is much lower when pus is present, and which 
therefore have relatively little effect in suppuration. 
The disease-producing bacteria which are affected by penicillin 
make an impressive list. Many of them are sensitive to just as high a 
dilution as the staphylococcus. Some are present in nearly every war 
- wound, so that the interest of the armed forces in penicillin is readily 
understood. This list is by no means complete. There have been 
some additions to the list of sensitive organisms, the most important 
of which—the 7’reponema pallidum—is that causing syphilis. This 
means that syphilis becomes one of the diseases which can be treated 
by penicillin. 
Bacteria affected by penicillin 
Sensitive : 
Streptococcus (childbirth fever and many cases of serious sepsis). 
Staphylococcus (boils, carbuncles, and serious infections of bone and other 
organs). 
Pneumococcus (pneumonia). 
Anthrax bacillus. 
Diphtheria bacillus. 
Actinomyces (“woody tongue” of cattle and sometimes human disease). 
Tetanus bacillus. 
Bacilli of gas gangrene. 
Gonococcus (gonorrhea). 
Meningococcus (spotted fever). 
Partially sensitive: 
Typhoid bacillus. 
Gaertner’s bacillus (food poisoning). 
Vibrio El Tor (cholera-like disease). 
Insensitive : 
Tubercle bacillus. 
Plague bacillus. 
Cholera bacillus. 
Brucella (undulant fever). 
Colon bacillus and related organisms. 
By all these methods penicillin was shown in the laboratory to be 
an extremely powerful antibacterial agent with low toxicity. The 
proof that it had chemotherapeutic properties, that is to say, that it 
would cure disease in living creatures, was also first supplied in the 
laboratory by what are known as “mouse protection tests.” Mice were 
