;74 Moral Epidemics and Contagions. [Oftober, 
3 . The contagious reflex movement, under the influence 
of the same causes, is not exerted equally, nor at all 
times upon all persons. 
Thus if any one yawns among those present, some aie at 
once induced to do the same; others either not at all or 
only after a second or a third repetition of the atfnon. 
In an independent work*' M. Rambosson has adduced 
some curious fadts on this subjedt. Thus repetition does 
much to determine the contagious reflex movement, a lact 
well known to physiologists as regards ordinary reflex 
movements. 1 
Each separate movement is added and accumulates, anc 
the sum of all these separate movements produces a reflex 
adlion more energetic than if the whole had ensued at once. 
Series of experiments have shown that such movements 
may assist each other even when separated by an interval 
of several seconds. 
We find in a classical workt the following passage : 
<{ An excitement too feeble to induce a reflex movement may 
become effective by being repeated. Ten, twenty, thirty 
slight shocks, repeated at intervals of a second, may in 
some manner add themselves together, and determine a 
reflex adtion even more energetic than would the sum ot all 
these small shocks adting at once. Mr. Stirling has re- 
marked that feeble excitements may multiply their effects 
even when they are separated by intervals of two seconds. 
In certain cases it has even been found possible to mea- 
sure the sum of the excitements necessary for the production 
of reflex adtion. 
4 . One and the same reflex movement may produce oppo- 
site effedts, according to circumstances. 
This phenomenon is important to establish, since its ex- 
planation becomes fruitful by the light which it throws upon 
all analogous fadts. 
For instance, a military march is heard. As soon as the 
sound-waves reach the brain of the hearers a reflex move- 
ment is produced which impels each one to follow in his 
own movements the cadence expressed. 
We often see even children manifest this with perfedt 
accuracy. 
* “ Les Phenomenes Nerveux Intelledtuelles et Moraux; leur Propagation 
par Contagion.” Paris : Firmin-Didot. 
| Beclard’s “ Physiologic,” 2e part., p. 426. 
