ACTION OF SALINE CATHARTICS BY N. B, DREYER, B. A. 181 



2.5 to 5 CO. of saline were Introduced into a length of gut about 

 four inches long. The movements remained fairly uniform in 

 character. This was confirmed on inspection; segmental and 

 peristaltic movements were easily discerned. The amount of 

 fluid recovered at the end of a ten minute period was never 

 increased above that put In; in some cases evidence of absorp- 

 tion of the sodium chloride was obtained. In the case of hy- 

 pertonic NaCl of 1.8% and 2.7% concentration, changes in the 

 movements soon became apparent. A gradual rise in tone 

 occurred together with more marked contractions. In both 

 cases the fluid increased in amount in the gut lumen. With 

 sodium sulphate the picture was slightly different and it seemed 

 to depend on the tone of the intestinal muscle. If the tone was 

 high, NazSO^, Isotonic with 0.9% NaCl, sometimes caused 

 depression. In the majority of cases where initial tone was low 

 isotonic NasSO^ caused marked Increase both of tone and move- 

 ments, but in no case was there a withdrawal of water from 

 tissues to the solution. With hypertonic solutions, Na2S04 

 exerted a very strong action. Almost from Its Introduction 

 segmental and peristaltic movements became marked, and in 

 some cases spasm of the gut was seen. The efi'ect on the con- 

 tents was even more marked than with N2CI In hypertonic 

 solutions. This was probably due to the fact that NaCl is 

 easily absorbed while N2SO4 is not. 



The Na2S04, if left too long, may eventually produce fatigue 

 and finally a condition not unlike paralysis of the gut. 



On removing the hypertonic Na2S04, and introducing normal 

 saline the movements diminished markedly and sometimes only 

 segmental ones were present. On renewing the 0.9% NaCl 

 repeatedly the gut eventually recovered. 



With magnesium sulphate in isotonic and hypertonic con- 

 centrations, movements disappeared completely. This is pecu- 

 liar since MgS04 has a marked purgative action in man. Since 

 the bile and pancreatic secretions were excluded from the gut, 

 and all connections with the central nervous system were severed 



