22 BIOLOGY 



which contain chlorophyl, and which are capable of transforming 

 the radiating energy of the sun into chemical energy. 



Not only through the industry of fermentation and agriculture 

 has technical biology asserted its place side by side with physical 

 and chemical technology, but also in the conquest of new regions 

 for civilization. As long as tropical countries are continually threat- 

 ened by epidemics, no steady industrial development is possible. 

 Biology has begun to remove this danger. It is due to Koch if epi- 

 demics of cholera can be suppressed to-day, and to Yersin if the 

 spreading of plague can now be prevented. Theobald Smith dis- 

 covered that the organisms of Texas fever are carried by a certain 

 insect, and this discovery has had the effect of reducing, and possibly 

 in the near future destroying, two dreaded diseases, namely, malaria 

 and yellow fever. 



It is natural that the rapid development of technical biology has 

 reacted beneficially upon the development of theoretical biology. 

 Just as physics and chemistry are receiving steadily new impulses 

 from technology, the same is true for biology. The working out of the 

 problems of immunity has created new fields for theoretical biology. 

 Ehrlich has shown that in the case of immunity toxins are rendered 

 harmless by their being bound by certain bodies, the so-called 

 antitoxins. The investigation of the nature and the origin of toxins 

 in the case of acquired immunity is a new problem which technical 

 biology has given to theoretical biology. The same may be said in 

 regard to the experiments of Pfeifer and Bordet on bacteriolysis 

 and hemolysis. Bordet's work has led to the development of methods 

 which have been utilized for the determination of the blood relation- 

 ship of animals. 



VIII. Ethical and Economic Effects of Modern Biology 



The representatives of the mental sciences often reproach the 

 natural sciences that the latter only develop the material, but not 

 the mental or moral interests of humanity. It seems to me, however, 

 that this statement is wrong. The struggle against superstition 

 is entirely carried on by the natural sciences, and especially by the 

 applied sciences. The nature of superstition consists in a gross mis- 

 understanding of the causes of natural phenomena. I have not 

 gained the impression that the mental sciences have been able to 

 reduce the amount of superstition. Lourdes and Mecca are in no 

 danger from the side of the representatives of the mental sciences, 

 but only from the side of scientific medicine. Superstition disappears 

 so slowly for the reason that the masses as a rule are not taught 

 any sciences. If the day comes when the chief laws of physics, 

 chemistry, and experimental biology are generally and adequately 



