1901 - 2 .] The Functional Inertia of Plant Protoplasm. 203 
xv. pp. 39, 669) supply examples of physiological insusceptibility. 
On swarming and other phenomena of individual cells, the 
experiments of Darwin, Detmer, Ewart, Farmer, Pfeffer, Mottier, 
and Vines, and many others may be referred to. Interesting 
cases of physiological insusceptibility are seen in nectaries (Pfeffer, 
Physiology , p. 286) in Pfeffer’s Chemotactic application of the 
Weber-Fechner law, and in a special set of phenomena in the 
life of parasitic fungi illustrated in the works of Eriksson, 
Marshall Ward and others — all tending to prove the universality 
of this property in plants. 
Isolated Organs. 
As the wheel, in virtue of its inertia of motion, continues to 
rotate for a time after the driving gear is slipped, so isolated 
organs or organoids may for a time manifest functional activity. 
This is an expression of their katabolic inertia. Isolated chloro- 
plasts continue to assimilate for five hours (Ewart, Jour. Linn. 
Soc., vol. xxxi. p. 424), isolated scutellar epithelium secretes 
enzymes, corrodes and dissolves starch (Brown and Morris, Jour. 
Chem. Soc. Trans., vol. lvii. p. 494), isolated endosperm of 
Bicinus grows for six weeks and carries on metabolic changes 
(Van Tieghem, Ann. d. Sc. Nat., 1876, p. 83), the nuclei of the 
staminal hairs of Tradescantia carry on Karyokinetic division after 
the cell protoplasm has been killed (Demoor in Pfeffer, Phys., p. 
52), non-nucleated fragments of Zoo-spores swarm and non- 
nucleated cytoplasm streams (Pfeffer, l.c., p. 51), translocation 
goes on in the ears of cereals (Pfeffer, l.c., p. 585), fruits ripen 
and oak galls continue their metabolism (MacDougal, Phys., p. 
64), after being removed from the plant. 
In the acquirement of new characters by living matter, it is 
suggested that functional inertia is a factor of importance. Some 
such fundamental property appears necessary to secure the sum- 
mation of effects and the more or less indelible stamping of these 
on the protoplasm. In this connection evidence is supplied with 
reference to the acquirement of polarity by Detmer ( Pract . Phys., 
p. 507), and periodicity by Darwin and Pertz ( Annals of Botany, 
l.c.). The following also bear on this point : Dubourg’s experi- 
ments on yeast ( Compt . Rend., vol. cxxviii., 1899, p. 440), the 
