128 BOTANICAL GAZETTE [aucust 
placed in the openings in such a manner that the roots grew 
down the glass tubes (fig. g). By this method it was impos 
sible for the roots to grow crooked. 
The seedlings of Zea Mais and Cucurbita Pepo were growl 
ina different way since germination took place more readily, 
and there was not so great a tendency to grow crooked roots 
The seeds were soaked in distilled water for twenty-four hours, 
and then placed carefully between sheets of moistened filter pape 
Care was taken to place the seeds in a flat position and in most 
cases the roots were straight, so that the extra work of a trails 
fer was avoided. In all cases the seedlings were allowed to grow 
until the roots had attained a length of about twenty millimeters. 
For the acids, zormal stock solutions} were used, that is, solutions 
of the mono-basic acids like HCl would contain one gral 
molecule of HCI per liter, while the di-basic acid like H, $0, 
would contain one-half gram-molecule of H, SO, pet liter, 8° 
that in each case the normal solution would contain one gram 0 
H per liter. For the stock solutions of the various salts, either 
solutions containing a gram-molecule per liter were used or solu” 
tions containing a certain fraction of a gram-molecule. For the 
seedlings of Pisum sativum the experiments were carried out ™ 
the following manner: The solutions in which the seedlings wer 
to be grown were placed in small beakers of about 300° capac: 
ity. A cork of sufficient size to close the opening of the be | 
was provided with a glass rod which extended down into the 
solution. On the end of the glass rod was a smaller cork, 4 | 
the seedlings were supported on this cork by means of B 
pins. The cork was then set at such a level that the cotyledons 
see the seedlings were just above the surface of the solutic A 
~ ape be made plain by the appended diagram i 
the seedlings of Zea Mais and Cucurbita Pepe * i 
ae 
3 . = 
ar RGR thanks are due to Dr. Kahlenberg for the majority of the stock-solution® 
0 to sits Schlundt for several salt-solutions. : 
