150 ROCHESTER ACADEMY OF SCIENCE. [Feb. 9, 
the priests in opening the breast before removing the heart. The 
knife is made of obsidian and is formed like a pruning knife with a 
curved point and with two cutting edges. 
In talking with Mexican archeologists while in the city of Mexico, 
my attention was called to the fact that, although the peculiar curved 
form of the sacrificial knives is carefully described in connection with 
the accounts of the human sacrifices, no such knife had ever been 
found or ever existed in any collection. Considerable doubt has been 
expressed as to the truth of the Aztec accounts of these human 
sacrifices, on account of the lack of the corroborative evidence of the 
sacrificial knife. I examined carefully the public and private collec- 
tion in Mexico and could find nothing different from the straight two- 
edged knife. I naturally reasoned that if these knives ever existed 
otherwise than in the imaginaticn of the early chroniclers, they would 
be found about the altar on the summit of the Temple of the Sun at 
Fic. 5. STONE TROWEL, Size 6 x 24% INCHEs. 
Teotihuacan, where so many bloody scenes of human sacrifice were 
said to have taken place. 
I made an expedition to this’place in 1875, and by a few moments 
digging about the altar on the summit, I was rewarded by finding four 
fragments of knives. All of them were nearer than six inches to the 
surface. 
Judging from the place where I found these relics, I think that all 
of them are fragments of sacrificial knives, although they do not all 
show the convex and concave cutting edges. 
Number one in the accompanying cut is unmistakably the point 
of a sacrificial knife. The concave edge is so decided as to leave no 
doubt as to its design. 
Number two, though not having the concave cutting edge, is differ- 
ent in form from the ordinary obsidian knife, and has no doubt been 
used in the human sacrifice. The fracture from the shorter cutting 
edge may have been caused by prying against a human rib in opening 
the breast to reach the heart, as was required by the Aztec priest. 
