158 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1945 



It was evident, too, that a further gain in weight and volume ratio 

 could be made if the sulfate ion in sea water was not removed. Cur- 

 rent opinions arising from Treasury standards emphasized that sul- 

 fate in drinking water should be at a minimum (250 parts per 

 1,000,000) owing to the suspected cathartic action of the sulfate ion. 

 In order to elucidate this point, experiments were conducted with 

 men placed on a semistarvation regime, who drank 500 milliliters to 

 1,000 milliliters of water per day prepared from sea water by the 

 Naval Medical Research Institute method (15). In this experiment 

 all the magnesium but none of the sulfate was removed. Ill effects 

 were not observed and all the sulfate ingested in the water (50 

 ME/liter) was found to be excreted in the urine. The evidence showed 

 clearly that this quantity of sulfate was completely absorbed from 

 the intestinal tract and was not retained by the tissues. Under these 

 circumstances it could not act as a cathartic. 



As already mentioned, the Permutit method was a single-step 

 chemical method. Its weight and volume ratios as originally em- 

 ployed, however, were extremely poor. It was demonstrated that if 

 the above adjustments in final chloride and sulfate content were made 

 and if a simple field kit were developed, the ratio of water produced 

 to apparatus employed could be increased to a point where it would 

 be superior to any other available method. The original low weight 

 and volume ratios were due to conformance to Treasury standards 

 which were not in accord with field requirements, and to the absence 

 of a practical field kit. 



The following recommendations were consequently transmitted to 

 the Permutit Co. : 



1. A collapsible processing container should be developed embodying the prin- 

 ciples worked out by the Naval Medical Research Institute and the National 

 Carbon Co., since this container had little volume or weight and was better 

 adapted to life-raft use. 



2. The chemical should be formed into highly compressed briquets to con- 

 serve space. 



3. Sodium chloride should be left in the drinking water to a concentration of 

 0.3-0.4 percent to increase the weight and volume ratio of the chemical and aid in 

 conservation of body water. 



4. The sulfate need not be removed to further increase the weight and volume 

 ratios. 



5. A lightproof and waterproof method of packaging as developed by the In- 

 stitute and the Reynolds Metal Co. should be employed since it not only offered 

 excellent protection against exposure to water and light but added little to 

 weight or volume. 



These recommendations were immediately adopted and prepara- 

 tions were made for raft trials, since it now had become obvious that 

 all the laboratory work done would be of no avail if the findings were 

 not proved to apply to actual field conditions. 



