BIOLOG'IC A L REVIEW. 
559 
appreciable effect. I then concluded that the seat of trouble 
was located in the nervous system and administered nerve 
tonics, the result of which was the elapse of five weeks be¬ 
fore another seizure of convulsions. The poor brute had 
twenty-six convulsions in two days, then went thirty-one days 
and was taken again, and during his fifteenth fit I terminated 
his sufferings. 
A post-mortem examination revealed the intestinal tract 
to be nearly normal, the lower portion of both lungs slightly 
diseased and all the other vital organs apparently normal. In 
the right ventricle of the heart, however, I found an intricate 
mass of worms resembling strongyli filarm. The average 
length of these parasites was about six inches, and they num¬ 
bered about twenty. Some of them had eaten into the tissue 
of the ventricle. Continuing my examination I found the 
ventricles of the brain softer than normal. Now there can 
be no doubt that this mass of parasites obstructed the venous 
circulation, and it is probable that this impediment to circu¬ 
lation caused the convulsions. 
BIOLOGICAL REVIEW, 
CONSIDERATIONS UPON THE FIRST PREMOLAR OF SOME DOMES¬ 
TIC MAMMALIA. By H. Lesbre. 
The first premolar in the dentition of mammalia is often 
absent, and when it exists it is always subject to caducity or 
to replacement. When it grows only once, it is by some con¬ 
sidered as a tooth of the first, and by others that of the sec¬ 
ond dentition. The author considers the first premolar of 
solipeds, of swine and of dogs as a milk tooth which has ac¬ 
quired permanence, and not as a product of the second denti¬ 
tion which has changed from a milk tooth. He says : 
. “ In solipeds the first premolar exists only on the upper 
jaw, and is only very exceptionally found in the lower ; it is 
a more or less rudimentary tooth, which he has found in all 
subjects of the age, at least, of thirty months. It resembles 
the milk molar in its form by having a neck and by the date 
of its eruption, which takes place not later than two or th’ee 
