68 BIOCHEMICAL SYSTEMATICS 



classic work of Baker and Smith (1920) on the terpenoids of Eucalyp- 

 tus. However, as early as 1901 Nuttall published his significant work 

 on the use of essentially serological methods in establishing species 

 relationships. These serological methods were, in turn, adopted by 

 numerous workers and extended to include a wide variety of organ- 

 isms, both plant and animal, over the succeeding several decades. In 

 its period of greatest emphasis (that is, during the period of 1920- 

 1930), the serological approach received mixed reactions. Some inves- 

 tigators embraced this development as a panacea which, almost alone, 

 would provide a completely objective approach to systematics gen- 

 erally. One prominent group of plant serologists emerged at Konigs- 

 berg, Germany, following the initial investigations of Gohlke in 1913, 

 Later, Mez was the dominant figure in the Konigsberg group. The 

 Konigsberg work culminated in the development of the much de- 

 bated, but now often overlooked, "Serodiagnostiche Stammbaum" 

 (Fig. 2-12) purporting to show a phylogenetic tree derived almost 

 entirely from comparative serological investigations (Mez and Ziegen- 

 speck, 1926). The serological data evoked in some quarters a con- 

 siderable amount of skepticism and in fact some severe criticism. 

 Most skepticism, as might have been expected, came from the 

 classical morphological systematists while violent emotional criticism 

 of Mez's contributions came surprisingly from other serological 

 workers, such as the Berlin group represented by Gilg and Schurhoff 

 (1927) who stated, "the serodiagnostic method is, for investigation of 

 plant relationships, completely useless." 



The controversy between the Berlin serologists and the Mez 

 group at Konigsberg was discussed by Chester (1937) in a series 

 of three general reviews of plant serology. These papers were master- 

 fully written, and they represent a classic summary of the early period 

 of plant serological investigations. The present authors are indebted 

 to Chester's review for much of the information on basic methodology 

 presented in the succeeding pages. It is ironic that at about the time 

 the Chester review appeared, interest and activity in plant serology 

 waned. Plant serological investigations have subsequently revived 

 somewhat, in Germany in the work of Moritz and in America by 

 Johnson and Fairbrothers. The revival of interest in America in 

 plant serology represents an offshoot from the animal serological 

 systematic studies of Boy den and co-workers, begun in 1925 and 

 continuing at Rutgers University. In the following paragraphs selected 

 examples will be drawn from zoological studies when they illustrate, 

 particularly well, a certain principle. In general, however, botanical 

 studies will be emphasized. 



It is doubtlessly recognized, by even the general reader, that 



