THE DEEPENING OF PHYSIOLOGY. 315 



interesting facts, e.g., that a fragment of a Protozoon, 

 if bereft of any representative of the nucleus, will 

 show contractility and irritability for a short time, 

 but has no power of nutrition, growth, or recupera- 

 tion. The work of Gruber, Balbiani, Hofer, and 

 Verworn on this by-path is of especial importance; 

 and with it we may associate the " tricks- with eggs '^ 

 which are played by the now numerous experimental 

 embryologists, such as Koux and O. Hertwig, Herbst 

 and Driesch. 



(d) Such organisms as Flowers of Tan (JEtlia- 

 livm [Fuligo] septicinn) afford large masses of 

 relatively undifferentiated living substance which 

 have been studied by the physiological chemist. And 

 similarly, it is possible to obtain quantities of Pro- 

 tozoa, Protophytes, leucocytes, spermatozoa, ova, etc., 

 in which structural differentiation is only im- 

 plicit. " A great variety of favourable research-ob- 

 jects are also found for microchemical investigation, 

 although thus far, since the methods are still little 

 developed, only the first beginning in this direction 

 has been made. The labours of Miescher, Kossel, 

 Lilienfeld, Loew, and Bokorny, Zacharias, Schwartz, 

 Lowit, and others, have already proved that the mi- 

 crochemical investigation of the cell has before it a 

 rich future." * 



AS REGARDS PROTOPLASM. 



The earlier observers, from Dujardin and Von 

 Mohl to Max Schultze, were well aware that the cell 

 contained or was a minute mass of substance, often 

 viscid^ often vacuolar, often apparently homogeneous, 



* Verworn, op. cit. p. 54. 



