544 
APPENDIX. 
24th of October, having been fourteen months from the United States ; 
more than eleven months of which had been spent at sea. The number on 
the sick-report on our arrival was thirty-four ; two of which had symptoms 
of scurvy, owing to -the long confinement to the ship and salt provisions. 
The symptoms were very mild, and did not manifest themselves until we 
came under the influence of the land-air : the first few days in port the 
disease became more severe ; after which they speedily recovered, and 
Were the only cases that occurred during the cruise. 
Shortly after our arrival liberty was granted to the crew, which, as 
usual, increased the number of sick. Ten cases were admitted with 
mania a potu, and a number with lues venerea. 
The Potomac remained forty days in the harbour of Valparaiso', during 
which time the average of the thermometer was 66°, and the barometer 
29.75. This is the spring in Chili, when high winds prevail from the 
south without rain. The sick-list was large for this port ; but could safely 
be attributed to the excesses and intemperance of the crew on shore ; 
thirty-five was our daily proportion, a majority of them having derange- 
ment of the stomach. 
Santiago, the capital of Chili, is situated ninety miles inland from 
Valparaiso, and has a population of forty-five thousand. It is remark- 
able for the extreme heat of the day and coldness at night, occasioned 
by the cold atmosphere from the snow-clad mountain immediately in the 
rear of the city, rushing down to occupy the place of the highly rarefied 
air in the plains below, in which the city is built. Remitting and bilious 
fevers prevail to a great extent ; but the most usual disease is goitre, 
which is frequently hereditary, and in some cases produces cretinism. 
The water that supplies the city is produced by the melting of the snow 
on the mountains, and to this the natives attribute the cause of the dis- 
ease. Iodine and the hydriodate of potassa are used with more success 
in the treatment than any other article in the materia inedica. While in 
Santiago, I heard of one case of extirpation of the thyroid gland ; the pa- 
tient did not recover. 
December 2d, sailed for Lima, where we arrived on the -15th. We had 
a south wind with pleasant weather during the passage, and on our 
arrival at Callao, the sick-list was reduced to eighteen. 
Remained in Callao seventy -five days, the thermometer ranging during 
that period at 70°, and barometer at 29.85. This is the most healthy 
season at Lima ; with clear, dry weather, the proportion sick was 
twenty-four. 
The ship was broken out, and well cleaned and painted, and the chlo- 
ride of lime freely scattered throughout the hold. 
Four cases of remitting fever occurred here ; they were attended with 
little arterial excitement, and would not bear the lancet. The sick-list 
of the ships of war in this port is usually large, and they frequently suffer 
much from dysentery. In July and August a constant mist and fog fills 
the atmosphere, which the inhabitants of Lima much dread. This wet 
season is very inimical to diseases of the lungs, and individuals predis- 
posed to phthisis (consumption) will be certain to have the disease devel- 
oped by a residence in Lima. One of our crew died from phthisis while 
in port ; and on our sailing for Valparaiso, an officer of the IJ. S. ship Fal- 
