CHARLES F. W. McCLURE 265 



These experiments should not be confused with the well known ex- 

 periments of Overton^ who ligated the cloacal opening but not the 

 ureters. When only the cloacal opening is ligated, the flow of urine 

 through the ureters into the cloaca and bladder is not interrupted. 

 The urine in such cases, as stated by Overton, will fill up the bladder 

 and then back up into the intestinal canal. When the ligature is 

 removed, this urine can be readily expressed from the body through 

 the cloaca. On the other hand, as we shall see in the following ex- 

 periments, after removal of the Ugature from the ureters, no fluid can 

 ordinarily be immediately expressed from the cloaca as, ill this case, 

 the excess of fluid contained in the body has been deposited in the 

 tissues and body cavity, and not in the bladder and intestinal canal. 

 The six experiments referred to in Table I were made during the 

 month of August. 



Experiment 1. — When killed the toad was in a comatose condition and had 

 gained 64.4 per cent in weight in 23 hours and 40 minutes. On removal of the 

 silk ligature no fluid was passed from the cloaca. A clear fluid containing albu- 

 min and weighing 6.4 gm. was removed from the subcutaneous lymph sinuses. 

 A clear fluid weighing 4.9 gm. which threw down a precipitate in nitric acid that 

 disappeared when acetic acid was added, was also removed from the body cavity. 

 An excess of fluid amounting to 3.4 gm. still remained in the tissues after re- 

 moval of the fluid from the lymph sinuses and body cavity. The lungs were 

 inflated and intensely congested. The blood vessels, especially those of the 

 abdomen, integument, and kidneys were also greatly congested. 



Experiment 2. — When killed the toad was partially comatose and had gained 

 66.5 per cent in weight in 16 hours and 55 minutes. No fluid could be expressed 

 from the .cloaca on removal of the small metal clamp with which the ureters had 

 been ligated. A bloody fluid weighing 11.6 gm. was removed from the subcu- 

 taneous lymph sinuses and 3.2 gm. of fluid of a similar character were found in 

 the body cavity, leaving an excess of fluid amounting to 5.5 gm. in the tissues of 

 the body after removal of fluid from the lymph sinuses and body cavity. The 

 condition of the lungs and blood vessels was essentially the same as in Experi- 

 ment 1. 



Experiment 3. — In this case the dorsal wall of the cloaca was tightly clamped 

 with an artery forceps, the teeth of which undoubtedly cut deeply into the 

 tissues. After being placed in water the toad gained 89.6 per cent in weight in 



* Overton, E., Verhandl. physik.-med. Ges. Wurzburg, 1904, xxxvi. 



