September 10, 1915] 



SCIENCE 



333 



diphtheria antitoxin, which was a direct out- 

 come of experiments devised according to the 

 side-chain idea. Ehrlich's method, to the ex- 

 clusion of others, is used all over the world; 

 but the influence of the work carried out to 

 test the side-chain theory of Ehrlich and 

 his pupils stm dominates investigation in all 

 branches of immunity and the practical use 

 of the knowledge obtained therefrom. 



The side-chain theory is so well known that 

 it is not necessary to restate it except in the 

 most succinct form. A toxin or other antigen 

 is without action on the animal body unless 

 bound by molecular chains in the cells — 

 receptors. But when so bound, the antigen 

 causes injury to the cell, and subsequent re- 

 pair, in the course of which there is an over- 

 production of receptors, which, passing into 

 the blood and lymph, constitute the antibody 

 for the antigen in question, because the anti- 

 gen is now bound and neutralized or destroyed 

 before it can reach the cell. As expressed by 

 Behring, antibodies are free cell receptors, and 

 the elements which, when situated in the cells, 

 are essential for the action of toxins, for in- 

 stance, are also the means of healing when 

 free in the blood. In accord with the prin- 

 ciples of this theory, Ehrlich's vivid mind 

 coined numerous new words, which proved 

 helpful in the discussion of new facts and 

 ideas, and which soon passed into current 

 international usage. 



Ehrlich's last work was the development of 

 the experimental chemotherapy of syphilis and 

 certain other spirochetal infections. To dis- 

 cuss this wonderful work fully in all its rami- 

 fications is not possible at this time. The scien- 

 tific world has accepted "the development 

 through a lengthy series of systematic bio- 

 chemical experiments, based on original con- 

 ceptions of the aflSnities of cellular constitu- 

 ents, of a successful chemotherapy of impor- 

 tant human infections, by direct attack on the 

 parasites by substances specially built up for 

 that purpose and introduced from without," as 

 the fitting culmination of the tireless activities 

 of an altogether unique investigative spirit. 

 As pointed out elsewhere, Ehrlich's results in 

 experimental chemotherapy fully justify Hux- 



ley's prediction in 1881 that through discov- 

 eries in therapeutics it would become possible 

 " to introduce into the economy a molecular 

 mechanism which, like a cunningly contrived 

 torpedo, shall find its way to some particular 

 group of living elements and cause an explo- 

 sion among them, leaving the rest untouched." 

 Paul Ehrlich will live in the history of civili- 

 zation as one of the great investigators, genial, 

 creative, fertile, excelling in " that boldness of 

 the scientific use of the imagination which 

 alone can extend beyond the obvious fact and 

 reveal the unknown," one of the great bene- 

 factors of mankind. 



THE NEW YORK BOTANICAL GASDEN 



The New York Botanical Garden at Bronx 

 Park is celebrating this week the twenty-fifth 

 anniversary of its foundation. The first ses- 

 sion was opened at nine o'clock Monday morn- 

 ing, September 6, with registration of dele- 

 gates in the library, followed by an inspec- 

 tion of museums, laboratories, library and 

 herbaria, with special reference to the exhibi- 

 tion of painting of plant life by Mary E. 

 Eaton in the herbarium, and the Charles 

 Pinney Cos collection of Darwiniana. After 

 lunch in the Museum Building the delegates 

 and guests were formally welcomed by W. 

 Gilman Thompson, president of the board of 

 managers; by Henry H. Rusby, chairman of 

 the scientific directors, and by Thomas W. 

 Whittle, commissioner of parks for the Bronx. 

 Dr. N. L. Britton, director-in-chief, then read 

 " A History of the New York Botanical Gar- 

 den." 



Tuesday, September 7, was set for the read- 

 ing of papers. According to the program these 

 included : " Mechanism and Conditions of 

 Growth," by D. T. MacDougal ; " Mosses from 

 Florida," by Elizabeth G. Britton; "Direct- 

 ing Factors in the Teaching of Botany," by 

 Arthur H. Chivers; "Flora of the Mammoth 

 Cave, Kentucky," by R. Ellsworth Call ; " Tri- 

 assic Plants from Sonora, Mexico," by Edwin 

 W. Humphreys, and "A White-Cedar Swamp 

 on Long Island and Its Significance," by Nor- 

 man Taylor ; " On the Nature of Types," by 



