40 
IOWA ACADEMY OF SCIENCES. 
I. THE MINUTE STRUCTURE OF PROTOPLASM. 
Any conception of cell-life must involve the microscop- 
ical architecture of living substance as such. The oldest 
view, and the one still widely current, presents protoplasm 
as everywhere having the structure of a reticulum holding 
more fluid matter in its meshes. The accuracy of this 
conception could not be tested before optical apparatus 
had been somewhat improved, and until the effects of 
laboratory reagents upon the microscopical appearance of 
protoplasm had been thoroughly grasped. 
Hardy took a step in the right direction through his fine 
studies of the structure of colloidal solutions and the 
effects of reagents upon them. Fischer, in a series of care- 
tully planned researches, applied our common fixing and 
staining agents, in accordance with biological usage, to 
proteids, proteoses, and peptones. Such work demon- 
strated that our laboratory methods, when blindly fol- 
lowed and implicitly trusted, are productive of altogether 
misleading pictures in stained and mounted preparations. 
Logically, the next contribution (although historically 
antedating the studies just noted) was made by Butschli 
from his investigations of artificial foams and emulsions, 
and in the application to protoplasm of the results so ob- 
tained. It was thus made clear that a series of alveoli 
would optically present the reticulum described by Heitz- 
mann, Leydig, Carnoy, Schafer, and Watase; or th q fibril - 
lae of Flemming and Schneider, when protoplasmic cur- 
rents and optical conditions are favorable; or the granules 
of Altmann, when nodes are emphasized, or when the 
reagents employed are productive of clumped artifacts. 
It was certainly a marked advance to have it shown that 
the earlier attempts to find exact uniformity of ultimate 
protoplasmic structure amid all diversities of living condi- 
tions were but partial expressions of one truth. 
Building on the foundation laid by Butschli, the An- 
drews in “The Living Substance” and later papers have 
brought to completion a conception of protoplasm which 
may well endure. It is a weighty discovery that the walls 
