104 E. R. HOSKINS AND M. M. HOSKINS 



the animal be kept immobilized. In collecting urine from an 

 immersed animal the receptacle can be sealed tight and weighted 

 to keep it under the water. A long glass tube leading into it 

 will permit the air to excape as the urine accumulates. If a long 

 rubber tube is used to connect the cannula with the collecting 

 bottle the animal can even be permitted to swim about in the 

 aquarium while the urine is being collected. Denis ('12) also 

 describes a good method for collecting urine. 



The duct of the digitiform gland enters the intestine at a 

 peculiar angle, being completely bent on itself. In order to 

 insert a cannula into the duct it is best to reach into the intes- 

 tine with a pair of blunt forceps and turn the gut inside out 

 through the cloaca. This straightens the duct and a cannula 

 can then be introduced directly into it. No anaesthetic is 

 required in operations as the animal will lie quietly in the ap- 

 paratus described above and seems insensible to pain. Anti- 

 septics were also found to be unnecessary in operations. 



EXPERIMENTS 



1. Solutions 



A. Indigo-carmine. 1. An adult male dogfish was injected 

 intramuscularly with 5 cc. of 0.5 per cent indigo-carmine. This 

 appeared in the urine in fifteen minutes. It did not appear in 

 the stomach, spiral-valve or digitiform gland contents, at least 

 in detectable quantities. The bile was bluer than normal. 



2. The experiment was repeated with a female, and similar 

 results obtained. 



3. Two animals, a male and a female, each received 5 cc. of 

 the above solution intravenously. It was recovered from the 

 urine of each after eight minutes. 



4. A female was injected as in '3' and permitted to live five 

 hours, at which time the urine was still dark blue in color. 



All five of the above-mentioned animals were autopsied at 

 various times after injections, varying from a half -hour to five 

 hours. All secretions examined gave the same reactions as in 



