_December 6th_.--I returned to San Francisco, and on the second evening attended a discussion at the Mercantile Library Association, on the subject of Governor Young, the Utah Mormons and the general government. Spoke several times, and was appointed to make the opening speech in one week from that time on the same subject, and to be answered by Rev. Mr. Briggs. FROM THE DAILY "ALTA CALIFORNIA" Mr. Parley P. Pratt, for whom we have considerable respect as a man and as a teacher, coupled with as much admiration of his talent as the doctrines which he employs to defend it will admit of, Mr. Parley P. Pratt appears to have walked into the temples of our money changers in this city, and fairly put to flight all reason and philosophy by the boldness of his attack upon the Christian Church. Our readers will remember Mr. Pratt as the self-confessed Apostle of Polygamic Mormonism in California, and its last exploit was to draw up on him the fire of a room full of debaters in the San Francisco Mercantile Library Association, and then commenced a bombardment of the citadel of their reason, and silenced or rendered useless every gun! For several weeks Mr. Pratt has been wheeling and charging his squadron of polygamic arguments in full sight of all our church doors and lecture rooms, and even advanced in person to the foot of our pulpits to proclaim himself the defender of a new faith, flinging the glove even into the minister's desk. Up to the present time, we believe, no David has gone forth against this Philistine to meet him on either point of law, morality or religion, which he declares himself ready to engage an enemy upon. We naturally ask, why is this? In a city with so many well supported churches and able divines, can no one be found to match this champion of the Mormons? Or are the abhorrence and contempt of such doctrines, and scorn of their advocates so great as to stifle the power of expression among our worthy controversialists? Either of these causes, we consider fallacious and bad. Passion should play no part in the impulses of Christian minds, and we much doubt the propriety of condemning a doctrine because of its low origin, or despising argument because it may not present a respectable exterior. Missionaries are sent to the heathen; and why should discussion be denied heathenistic doctrines when they are brought to our own very doors? We have very worthy and respectable street preachers in San Francisco, and we do not see how a religious discussion with a Mormon would profane the walls of any one of our churches, or taint the reputation of any of our ministers of the gospel. Mr. Pratt seems to have the best of the law on his side so far as the situation of the Salt Lake people is concerned; under our territorial regulations there really appears to be no law to prevent Polygamy. _December 9th_.--Returned to Santa Clara by steamer and stage, and found all well.