395 
As a periodical series of four terms was em- 
ployed to distinguish the years contained in a 
cycle, the Mexicans were very naturally led to 
quadrennial festivals. Such was the solemn fast 
of one hundred and sixty days, celebrated at the 
spring equinox, in the petty republics of Tlas- 
calla, Cholula, and Huetxocingo ; and the hor- 
rible sacrifice, which took place every four years 
at Quauhlitlan, in the month of itzcaili, when the 
penitents scarified their bodies, letting the blood 
run along reeds thrust into their wounds^ and 
hanging up these reeds in the temple, as public 
marks of their devotion. These festivals, which 
remind us of the acts of penitence at Thibet and 
in the Indies, were repeated each time that the 
same sign presided over the year. 
On opening, at Rome, the Codex Borgianus 
ofVeletri, I there found the curious f)assage^, 
from which the Jesuit Fabrega concluded, that 
the Mexicans had knowledge of the real dura- 
tion of the tropical year. Twenty cycles of fifty- . 
two years, or one thousand and forty years, are 
there indicated in four pages : at the end of this 
great period, we see the sign rabbit, tochtli, im- 
mediately^ precede, among the hieroglyphics of 
the days, the bird, cozquauhtli ; so that seven 
* Gomara^ p, 131. Torquemada, tom. ' 1 ^ p, 307. Ge- 
melli, tom. 6, p. 75. 
t Cod. Borg, foli 48—63. Fabrega, MSS. fol. k, p, 7. - 
