Blackman and Paine.—Studies in the 
78 
autonomous or autogenic in nature, i. e, occurring when the external con¬ 
ditions of temperature, light, &c., were quite constant 
The first occasion on which they were observed was on April 4, 1913, 
when a pulvinus was placed in water in the cell at a temperature of 29*9° C. 
and brightly illuminated. Twenty-nine minutes after cutting it reacted to 
the stimulus of cooling, and after several stimulations in this way when 
replaced in the fluid it exhibited a series of nine contractions. The interval 
between two successive contractions was at first about 4 min., but it 
gradually decreased till the interval between the last and penultimate con¬ 
tractions was reduced to 1 min, 53 se<j». 
This striking phenomenon was observed on some ten occasions at 
temperatures between 30° and 40° C.; in all cases the pulvinus was brightly 
illuminated. The contractions as they proceeded were always found to 
occur at shorter and shorter intervals, with the result that the extent of the 
contractions gradually decreased, since the pulvinus had less and less time 
to straighten between successive contractions ; the pulvinus thus finally came 
to rest in the partly contracted state. A graphic representation of one of 
these series showing sixteen autonomous movements is given in Fig. 3. 
Bose ( 5 ) has observed a similar series of movements following on 
a single stimulation in Biophytum and Averrhoa , and he applies to them the 
term ‘ multiple response ’, pointing out, however, that no sharp line can be 
drawn between multiple responses and autonomous movements. 
