76 D. NOEL PATON, B. P. WATSON, AND J. KERK ON 



former are somewhat unsatisfactory, not only on account of their small size, but also from 

 the fact that in both the development of the allantois is very incomplete. The same 

 objection does not apply to the dog or cat, although in our hands the cat proved unsatis- 

 factory, from the small amount of fluids in the later stages of gestation, when alone it 

 was possible to be sure that the animals were pregnant. 



The method of procedure was to anaesthetise the animal, to fix a cannula connected 

 with a burette containing the solution to be injected in the proximal end of the 

 jugular vein, and to let the solution run in very slowly. In some experiments one 

 cornu of the uterus, with its contained pregnant sacs, was removed to serve as a check, 

 but in later experiments this was not done. 



When a sufficient quantity of the fluid had been run in — a good indication of this 

 being given by the intense staining of the mucous membranes with the fluorescin — the 

 injection was stopped and the animal allowed to live for from 10 to 20 minutes, being 

 kept all the time under the anaesthetic. The uterus was then excised and the animal 

 killed by pushing the anaesthetic. 



The uterus was at once removed to a clean table, and each sac was carefully opened 

 and the fluids collected in carefully cleaned vessels, care being taken to prevent any 

 admixture with the maternal blood. The foetuses were then removed, weighed, and if 

 any urine was present in the bladder it was collected. Sometimes the foetal blood was 

 collected. 



The presence of fluorescin was recognised by its fluorescent appearance even in the 

 most dilute solution ; and the amount was estimated by the intensity of the fluorescence. 



Salicylic acid was tested for with a dilute solution of ferric perchloride, and the 

 depth of colour gave a fair index of the amount present. 



Sodium ferrocyanide was tested for with ferric chloride. 



Sodium iodide was tested for by the method given in the Appendix. 



The following experiment may be given in extenso as typical : — 



Experiment IX. — Irish terrier bitch, about 13 kilos., supposed to be seven weeks 



pregnant. 



On December 14, anaesthetised at 10.30, and two sacs of the right cornu of the 



uterus at once excised. A cannula placed in the jugular vein and the following solution 



run in from a burette : — 



Sodium iodide ........ 10 grms. 



Sodium salicylate ........ 5 gnus. 



Fluorescin . . . . . . . . 0"5 grms. 



Water f . 100 c.cm. 



The injection began at 11.12, and at 11.42, 150 c.c. had been injected (i.e. 15 grms. of 

 sodium iodide, 7 "5 grms. sodium salicylate, 075 grm. fluorescin). The dog was bled to 

 death at 11.50. Eyes strongly fluorescent; skin and all the organs deeply stained. 

 Blood-serum, bile, and urine intensely fluorescent. 



