340 J. M. D. OLMSTED 
pani nerve. In dogs with a short deep jaw, the bulldog type, it 
is almost impossible to disclose the chorda along a sufficient length 
if damage to the surrounding tissue is to be avoided. But in 
dogs of the collie type with long shallow jaws the operation is 
much simpler, especially if the dog is fairly large. Eleven to 
fourteen days after these three operations the dogs were killed, 
the tongues removed, and preparations of the papillae made. 
Six or seven papillae from each dog were examined and all were 
found to be normal. None had less than two taste buds and the 
average for each was slightly over four. The three heads were 
dissected and in all of them both the chorda tympani and lingual 
nerves on the operated side were intact. 
In another dog the left mandibular nerve was cut just craniad 
to the entrance of the chorda tympani (fig. 1). The dogs with 
the chorda severed seemed to experience no difficulty in eating 
or drinking, but were able to use their tongues quite normally. 
The chorda therefore does not carry efferent fibers to the muscles 
of the tongue. But this one dog with the mandibular nerve cut 
had great difficulty, especially in drinking. The left side of the 
tongue was paralyzed so that the margin could not turn up to 
form a rim along the edge of the tongue. Consequently, as the 
animal tried to lap up water from a dish the water ran out the 
left side of its mouth. The dog was killed on the twelfth day 
after operation. Dissection showed that the operation was suc- 
cessful for the chorda was intact, and that the mandibular just 
dorsal to it was severed. Fourteen fungiform papillae were 
taken at random from different levels of the tongue from the tip 
to three-fourths of the way back. Every one of them contained 
at least three normal taste buds and none of them showed signs of 
degeneration. 
Since so many representative papillae from all parts of the an- 
terior three-fourths of the tongue showed no change in their taste 
buds after cutting the mandibular nerve, while taste buds were 
absent or in the act of disappearing from papillae taken from 
similar regions in dogs with the chorda cut, it seems very reason- 
able to assume that all the taste fibers from this region of the 
dog’s tongue pass to the brain through the chorda tympani and 
that the lingual carries the motor fibers to the muscles. 
