5O INFLUENCE OF CHEMICALS 



73. Effect of Chloroform upon Mimosa, Place a sponge sat- 

 urated with chloroform near a vigorous expanded specimen of 

 Mimosa and cover with a bell-jar, being careful not to give the 

 plant a mechanical shock. Does the action of the vapor cause 

 movement ? After ten minutes remove the jar and apply shock 

 stimuli. Determine the length of the period necessary for the 

 plant to recover irritability to mechanical stimuli. Allow a second 

 specimen to remain under the bell-jar for a day with chloroform 

 vapor and note results. 



74. Effect of Chloroform upon Oxalis Leaves. Add i cc. of 

 chloroform to 200 cc. of water in a bottle and shake. Cut a leaf 

 of Oxalis into narrow strips and place them in the liquid. The 

 length of time necessary for the chloroform to kill the tissues may 

 be determined accurately since the leaf assumes a dingy yellow 

 color upon death. 



75. Degree of 'Molecular Complexity and Intensity of Poison- 

 ous Action. The series of alcohols of the lower paraffins affords 

 a convenient means of demonstration of the correspondence of 

 molecular complexity and intensity of poisonous action. The 

 formulae for some of the alcohols are as follows : 



Methyl, H CH 2 OH. 



Ethyl, CH 3 CH 2 OH. 



Propyl ; norm., CH 3 .CH 2 CH 2 OH. 



Propyl ; iso., CH 3 CH.OH CH 3 . 



Butyl; norm., CH 3 .CH 2 .CH 2 . CH 2 OH. 



Butyl ; iso., 3 >CH CH 9 OH. 

 Url 3 



Butyl; tertiary, ^ 3 >COH CH 3 . 



Amyl ; norm., CH 3 .CH 2 .CH 2 .CH 2 . CH 2 OH. 



Prepare two series of six small dishes in which colonies of 

 Spirogyra may be grown. Make solutions of ethyl alcohol and 

 of methyl alcohol containing the following concentrations ; normal, 

 | normal, \ normal, normal, \ normal and ^ normal. Nor- 



