2516 • Journal of Applied Microscopy 



(g) The efifect of an anaesthetic on the ability of a contracted organ to regain 

 its position of rest. The stamens of a flower floating on water are to be caused 

 to contract, and the preparation immediately placed under the bell-jar containing 

 chloroform vapor. The subsequent behavior of the flower is to be observed. 



■2. Experiments with tlie Sensitive Plant, Mimosa pudica. In the following 

 experiments use small potted plants and work in bright light. 



(a) When the leaves of the plant are all well expanded, the pot may be gently 

 raised and then set down upon the table with a heavy jar. The behavior of the 

 plant is to be closely watched to determine the differing action of the various parts 

 of the leaf. If the action was not followed for each part, the plant may be 

 allowed to regain its expanded condition, and the jarring repeated. 



(d) Beginning again with an expanded plant, the various parts of the leaf 

 may be explored with a bristle for sensitiveness. By this means a careful record 

 can be made of the most sensitive part of the leaf, and of the response following 

 stimulation in various places. 



(c) Allow the plant to regain its fully expanded condition, or take a fresh 

 plant, and determine the latent period at a definite temperature. Allow the 

 plant to regain its expanded condition. Stimulate again at the same temperature 

 and in the same way, and determine again the latent period. Continue to repeat 

 the test till the plant shows a great change in its response. 



(//) Place a plant under a bell-jar and when it is fully expanded introduce a 

 watch glass containing ammonium hydrate. If the plant gives any response, 

 remove the bell-jar quickly to save the life of the plant. 



(e) After causing the leaves of a plant to contract, cover it with a bell-jar 

 under which there is also a small dish of chloroform. Note the subsequent 

 behavior of the plant. 



3. Experiments with the Leaves of Oxalis. These experiments should be per- 

 formed in the sunlight. 



(a) A potted oxalis with the leaflets of a leaf all lying in one plane is to be 

 selected. This may be jarred severely as was Mimosa and the result looked for, 

 the latent period and the temperature being noted, also the period required for 

 regaining the expanded condition. 



(/i) Fully expanded leaves may be explored with a thin rod of glass, or wood, 

 or metal, and the attempt made to locate the area of greatest sensitiveness. 



(/) Determine whether the strength of the stimulus has any relation to the 

 time and intensity of response. To accomplish this result, stimulate some wholly 

 expanded leaves by striking the sensitive area gently with a glass or metal rod, 

 ■while corresponding areas of similar leaves are struck severely. Note the latent 

 period in each case. 



4. Experiments with Tendrils, (a) Each student may select some tendril bear- 

 ing plant growing in the open. He may then, by fastening wire or small wooden 

 rods in suitable places, determine the sensitive area of the tendril, the latent 

 period (the temperature being noted), the mode of action, and the relative age 

 of tendrils responding best to the stimulus. 



(/;) Five grams of gelatine are to be dissolved in 45 c. c. of warm water. A 



