106 NATIONAL TRENDS IN BIOLOGY 



ing Board in London for the purpose of breeding insect 

 parasites. These parasites will be shipped to all parts of 

 the Empire, for agricultural purposes, wherever they may 

 be needed to destroy noxious insects or plants. 



Next, as a world influence, was the delivery of the 

 Gifford Lectures in 1922, at the University of St. Andrews, 

 by C. Lloyd Morgan. His theme of Emergent Evolution, 

 published the following year, has brought forth what 

 many biologists and philosophers consider a veritable via 

 media that will solve the problems of Mechanism and 

 Vitalism alike. 



The foremost work and workers are : 



1. Hardy and (2) Fischer, who showed that the cyto- 

 plasm had no visible structures, and that the older reticu- 

 lar, fibrillar, or other appearances described in detail in 

 the later years of the nineteenth century, are artifacts due 

 to fixing and staining. Such appearances can be mimicked 

 in many other substances, such as the white of an egg, 

 and the same cell will show different structures depending 

 on the way it is treated. Yet the t)^ical cell remains a 

 microorganism with all its structures — nucleus with 

 chromosomes and linin network, etc., mitochondria, chro- 

 midia, Golgi apparatus, centrosomes, etc. ; 



3. Hopkins and (4) Willcock, whose Amino Acids in 

 Metabolism (1907) foreshadowed the finding of accessory 

 food factors which could not be analyzed chemically, and 

 which led to the discovery of vitamins ; 



5. Allen, whose work on the Artificial Culture of Marine 



