Rollo, with the aid of Cruickshank, carried out laboratory studies with his patients to ascertain the results of treatment and to elucidate the nature of diabetes. The fluid intake, urine output and the body weight were determined. The urine was tasted to indicate the presence of sugar and subjected to experiments before and after evaporation to determine its chemical composition and content of sugar. At the beginning of treatment when Captain Meredith was passing up to twelve quarts of urine in twenty-four hours, the following notes were made: 

"Mr. Cruickshank took 36 ounces troy weight of urine voided today, and it yielded by evaporation three ounces and one drachm of saccharine extract, of the appearance of molasses, but thicker, having nearly the consistence of wax, and somewhat tenacious. If, therefore, the whole of the day's urine had been evaporated it would have yielded about 29 ounces troy weight, an astonishing quantity to be formed and seperated form the system. By standing in the air it became moist, and of nearly the consistence, smell and appearance of treacle." 

"Treating some of this extract with the nitrous acid, he procured the saccarine or oxalic acid; and with a smaller proportion of the acid it produced a substance, which in resemblance, and smell, could not be distinguished from honey."