MAUTHNER’S CELL 113 
cell runs in the tract of the nucleus motorius tegmenti, namely 
the fasciculus longitudinalis medialis, in company with the Mil- 
ler’s fibers, and connects up with the same classes of motor cells. 
Mauthner’s cell differs from the other cells of the nucleus in its 
direct, intimate connection with the periphery. It has carried 
the short-circuiting one step farther than the Miiller cells, so 
that it is part of a three-neurone reflex consisting of an acoustic 
ganglion cell, Mauthner’s cell, and a motor cell of the ventral 
horn. The reduction of the latent period by the elimination of 
the synapses and the highly medullated character of the system 
have led me to believe that we are dealing here with a reflex in 
which speed and precision are very important, and I would sug- 
gest that it is this reflex which enables the animal to keep perfect 
control of its equilibrium in the most rapid and intricate move- 
ments. We find the system most highly developed in the tele- 
osts, whose tail swimming is ne plus ultra. If, as Edinger and 
others have taught, Mauthner’s cell were part of the general 
tonus reflex, it is hard to see why it should have been so inti- 
mately related to the tail-muscle nuclei as to disappear as soon as 
the tail is lost in the anuran Amphibia. There are other reasons 
for believing that Mauthner’s cell serves to keep the animal in 
equilibrium by means of tail and fin movements, rather than that 
it distributes tonus impulses generally to the somatic muscula- 
ture. In the first place, it connects only with motor nuclei cau- 
dal to the motor VIIth root and in the adult the collaterals of 
Mauthner’s fiber seem to be chiefly related to the fin and tail 
nuclei (Taglani 05). Secondly, the great caliber of the axones, 
the broad contact surfaces in the synapse of the lateral dendrite, 
the highly insulated character of the whole path and the short- 
circuiting just referred to, all point to a very rapid reflex. Thirdly 
it must be remembered that Mauthner’s cell has connections, not 
only with the VIIIth nerve, but from every center in the brain 
which receives impulses that may be used in equilibration (p. 
109). 
It is by no means necessary, however, that Mauthner’s cell be 
concerned only in equilibratory reflexes. It has been said that 
