380 BOTANICAL GAZETTE | DECEMBER 
hydrate has the formula KOH. K, O and H have respectively 
the atomic weights 38.85, 15.88 and 1. Therefore the molecu- 
lar weight of KOH is 55.73. Then 55.738" of potassium 
hydrate dissolved in one liter of water constitutes a normal 
solution of potassium hydrate. 
It will be readily seen then that, the work being accurately 
done and the molecular formule being correct, a normal solu- 
tion of any substance will contain as many molecules per cubic 
centimeter as a normal solution of any other substance. 
In a few cases solutions of greater than normal strength were 
used, but generally, if the substance did not prevent growth when 
in one-tenth of normal strength, the substance was considered 
non-poisonous and was not experimented with further. 
Starting with a normal solution, dilutions were easily made 
till such strength was reached that the spores would germinate 
The various strengths used are designated as fractions of normal 
Thus ,%., signifies a solution of one eight-hundredth normal, a 
strength which could be prepared by taking one cubic centi- 
meter of normal solution and diluting it to 800%. Ten cubic 
centimeters of ,*. diluted to 80% would furnish exoy etc 
The atomic weights used are those given by Roscoe and 
Schorlemmer.? 
TABULATION AND DISCUSSION. 
In tables I-XVI appears a record of the cultures made, more 
than 1500 in all, each culture bearing from fifty to a few thou- 
sand spores. The fraction shows the strength of solution used, 
and the figure to the left of the fraction shows the number of 
times this strength was tried. If the fungus grew, the strength 
in which it grew appears in the corresponding column. Those 
strengths in which it failed are to be found in the column headed 
Failed. Reference to a footnote indicates some peculiarity 
regarding the culture, which will be found explained in the note. 
The numbers used in these footnotes are original numbers of the 
cultures. 
? Treatise on Chemistry 1 : 52. 1895 [ed. 3]. 
