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connected with physiology, and in this way to verify the state- 
ments made. One or two illustrations may be taken from the 
prominent discussions now occupying plant physiologists. 
Anatomy may be divided into, or it consists of two parts, that 
of the cell, and that of tissues. In the study of the cell, for con- 
venience, it is treated as wall and contents. With the contents as 
the seat of life, or Lebens-trager, are connected most of the ques- 
tions concerning nutrition or the changes undergone in substance 
used as food. With the wall, as well as with certain parts of the 
contents, are connected questions of organized structure among 
which are some of the most absorbing interest and in whose solu- 
tion some of the keenest thinkers of the time are employed. 
Wiesner has recently published a book entitled “The Elemen- 
tary Structure and Growth of Living Substance,” in which he pro- 
poses a theory in several respects directly opposed to the accepted 
one which is known as the micellar theory of Naegeli. For ex- 
ample, according to the latter theory, the units of structure or 
micellae of organized matter are held together by the law of at- 
traction and the cause of enlargement of such structures on taking 
in water is due to the penetration of water between the micellae 
of the substance composing the structure. According to Wiesner 
the units of structure are held together by fine protoplasmic strings, 
and as water is drawn away, by evaporation, the interstices between 
the units are filled with air; if water be added it is taken into the 
units themselves, which become enlarged proportionately; the 
change in volume caused by change in water contents depends, 
therefore, on change in the diameter of the units, and not on the 
lengthening or shortening of the protoplasmic strings. . 
Physiology treats of how a living organism grows and performs 
its various actions; this question, therefore, lies at the very founda- 
tion of physiology, as on it depends largely the manner of 
growth and other forms of motion. This will be seen by 
considering such subjects as the law of leaf position. Were 
Wiesner’s theory the correct one, Schwendener’s law, which is 
based upon Naegeli’s theory would fall to the ground, and another 
reason must be sought in consonance with the facts. The posi- 
tion and authority of Wiesner is too well known to require mention _ 
here, and it is probably equally well known how strong are the _ 
arguments against most of the peculiar views which he advocates. 
