Before leaving Vicksburg the crews of the fleet had suffered severely from the sickness common in that climate. The Brooklyn had sixty-eight sick out of a total of three hundred; and as this proportion was less than in the upper river flotilla, where the sick numbered forty per cent of the total force, it is probable that it fairly represents the general condition of Farragut's ships. Among the troops accompanying the expedition there were but eight hundred fit for duty out of over three thousand. It was not considered well to maintain for a longer time in Baton Rouge the small garrison hitherto stationed there. It had honorably repulsed the enemy's attack; but, in the general cessation of offensive movements by the United States army, the Confederates were continually strengthening their forces on the line of bluffs south of Vicksburg, to the importance of which their attention, never entirely diverted, had been forcibly drawn by the advance of the fleet in the previous months. Fruitless as that ill-judged advance had been, it reminded the enemy of the serious inconvenience they would suffer if the United States ships could freely patrol that part of the Mississippi, and impressed upon them the necessity of securing a section of it, by which they could have undisturbed communication between the two shores. This could be done by fortifying two points in such strength that to pass them from either direction would involve a risk too great to be lightly undertaken. The points chosen were Vicksburg and Port Hudson, two hundred miles apart, and embracing between them the mouth of the Red River. The latter is the great artery of the region west of the Mississippi, and also, by means of the Atchafalaya Bayou, offers direct communication for light-draught vessels with the Gulf of Mexico. Port Hudson being less than twenty miles from Baton Rouge, the presence in the latter of a small garrison, which could undertake no offensive movement and which there were no troops to re-enforce, became purposeless. On the 16th of August, 1862, the post was abandoned, and the troops occupying it withdrew to New Orleans. CHAPTER IX. THE BLOCKADE AND PORT HUDSON. 1862-1863.