1 U v» 1 1 
Coi tbohc.Acil 
7JUo\ol 
In this series we have used for comparison some of t ho alkaloids, 
acids, salts and organic compounds and mixtures which are well known for 
one or more of the properties under discussion. 
The chart illustrates, more graphically than can be shown by figures, how 
widely these substances differ among themselves, how great the difference 
in intensity is between the properties of one substance, and what 
may be accomplished by a mixture of two of them. 
Comparing Mercury and Arsenic compounds, both have high toxicities to 
vertebrates but the former have a selective toxicity toward bacteria or vege- 
table life, and the latter toward the lower animal life or Arthropoda. This 
same selective action is seen in the case ol the two alkaloids, Nicotine and 
Morphine. Nicotine is toxic toward animal iite but not vegetable. Morphine 
is not particular! \ toxic in any respect to the lower animal or vegetable 
life. 
Comparing the values of Carbolic Acid. Crcsylic Acid and Coal Tar Disin- 
fectant, all of which are made soluble by mixture with soap; they form an 
ascending series in their germicidal and insecticidal actions, while the reverse 
is true of their toxicity toward vertebrates. 
Coal Tar Insecticide, having the same origin as the others and the same 
toxicity toward vertebrates as that of the Disinfectant, shows a remarkably 
selective action in its toxicity toward insects. 
These cases serve to point out a few of the drugs which have decidedly 
selective action toward certain organisms. 
