Rational treatment of cholera cannot be provided without precise knowledge of the water and electrolyte losses which occur in this disease; such information is not available in the literature. Studies prior to 1900 usually reported electrolyte concentrations in whole blood, not in plasma, and sodium and chloride were frequently reported as NaCl. Since 1900 there have been many reports of electrolyte concentrations in plasma or fecal excreta but only one preliminary report (1) relates fecal losses to plasma levels in the same patient. However, this report suffers, as do all others on cholera, from the fact that oral intake was not restricted and it is not certain to what extent fecal electrolytes had been diluted with oral fluids.The 1958 cholera epidemic in Bangkok, Thailand, provided the opportunity to perform quantitative, volumetric studies of water and electrolytes in plasma, feces and urine for the first 24 hours after admission in patients suffering from cholera. During this period oral food and fluids were withheld and the dehydration and acidosis were treated by intravenous fluids. The effect of water and sodium loading on electrolyte exchange was also observed and whole blood and plasma analyses were repeated on each patient in convalescence. MATERIALSTwenty-five patients with diarrhea were admitted to a study ward provided by the Chulalongkorn University Medical School at the Bangkok Red Cross Society Hos-* The opinions and assertions contained herein are those of the authors and are not to be construed as official or reflecting the views of the Navy Department or the Naval Service at large. Care was taken to avoid spillage of feces. A large bore rectal tube was used for the first 24 hours in addition to a cholera bed in which the patients' buttocks were placed over an opening in the bed frame and excreta collected in five gallon containers. Retention catheters were placed in the bladder for the first 24 hours to facilitate urine collection. Urine and feces were measured in graduated cylinders to the nearest 5 ml. Aliquots of fecal material were filtered through glass wool and a Seitz filter. Blood samples were heparinized and the plasma separated immediately after a sample for duplicate hematocrits and whole blood specific gravities had been obtained. Fecal specimens and blood for plasma CO2 content were collected under oil and analyzed within 20 minutes. During the first 24 hours of observation and treatment, patients were given nothing by mouth with the exception of four who were given carmine dye with 100 ml. of water in order to measure bowel transit time. After 24 hours, fluids were given ad libitum and a diet of rice gruel, boiled eggs and milk was allowed. All patients received an antibiotic, either chloramphenicol or a tetracycline derivative, after the 24 hour observation period and had at least one cholera-negative stool culture prior to discharge. Patients 13 and 18 probably had cholera but repeated attempts to culture the V. comma were unsuccessful.1879