Effect of Saline Purgatives. 



333 



phenomenon led the author to inquire into what effect the admin- 

 istration of such purgatives may have upon the absorption of other 

 drugs given by mouth simultaneously or a little after the laxative. 

 Accordingly experiments were first made with phenolsulphon- 

 phthalein. This drug, as is well known, is rapidly absorbed, whether 

 given by injection or by the stomach, and is equally as rapidly 

 excreted by the kidneys. Several dogs were given a given quan- 

 tity of a solution of phenolsuphonphthalein by stomach tube and 

 the amount excreted in the urine at the end of one and two hours 

 was determined quantitatively by the colorimetric method. Sev- 

 eral days later after the drug had been completely excreted, the 

 same amount of dye with the same amount of fluid was adminis- 

 tered to the same animals by the same method, with the excep- 

 tion that the dye was this time mixed with a solution of sodium 

 sulphate (5 per cent.) instead of plain water. The excretion of 

 the dye by the kidneys was studied at the end of each hour as in 

 the first series of experiments. It was found that the excretion 

 of the phenolsulphonphthalein was markedly delayed by the si- 

 multaneous or previous administration of sodium sulphate. The 

 same was true of magnesium sulphate and other saline purgatives, 

 but no such effect was produced by the administration of other 

 cathartics of a non-saline character such as castor oil or cascara 

 sagrada. 



To study the mechanism of the above phenomenon more in 

 detail, experiments were then made on cats. The animals were 

 anesthetized, laparotomy was performed and two loops of intes- 

 tine of exactly the same length were tied off, in some experiments 

 in the same animal, and in other experiments in two separate 

 animals. Into one loop 1 c.c. of standard phenolsulphonphtha- 

 lein solution mixed with a given volume of water was injected. 

 Into the other loop exactly the same amount of dye was mixed 

 with exactly the same volume of sodium-sulphate solution. The 

 intestines were replaced in the abdominal cavity and the abdomen 

 closed. At the end of an hour the animals were killed and each 

 loop of the intestine was cut out and its contents carefully meas- 

 ured. It was found that in the control loops, that is, the loops 

 containing a solution of the dye in water, much of the fluid was 

 absorbed and the amount of dye remaining in the contents of that 



