384 Royal Society : — 



flow, then repeated cleanings and got three minutes more. My 

 estimate at the close of the operation was that the silver-grey gave 

 blood freely for thirty-five minutes, and received it freely for about 

 the same time. 



II. Experiments of cross-circulation on two bucks and two does of a 

 silver-grey breed, reputed pure, and looking well-bred animals, but 

 liable to show russet marks. They were procured of iMr. Vipan, of 

 March, Cambridgeshire, and are of the same breed as those on which 

 Mr. Bartlett made his well-known experiments about the production 

 of Himalayas (Proc. Zool. Soc. 1861). They are liable to throw 

 " Sandy Himalayas," as I found myself, as Mr. Bartlett also found, 

 and as Mr. Vipan informs me is the case. I distinguish this breed 

 by asterisks (*). 



Oct. 6, 1870. — Silver-grey buck, V*,mo([evaiesizQ; his blood-mate 

 was a Commo7i grey buck, with some russet on his back 



and white on his belly ; he was the larger of the two animals. 



12'' 50", cross-circulation established, perfect ; 12'' bo"", ditto, but 

 silver to common, I think, a trifle the stronger; 12'' 59™, ditto; 

 l'' 5", common to silver very faint. I stopped them and cleaned 

 out twice and successively; 1'' 15™, good, but common to silver was 

 the least good; 1'' 25"", disconnected. My estimate was that there 

 had been an equivalent to fully twenty-five minutes, and perhaps 

 thirty minutes, of capital flow both ways. 



Oct. 7, 1870. — Silver-grey buck, Q*, moderate size; his blood- 

 mate was a Yellow buck, white belly, large. 



jjh ^Qm^ cross- circulation established; II'' 45"", quite good; 

 11'' 50™, good but not perfect; 11'' 5 S™ good; 12" both stopped. 

 Then I made several disconnexions and cleanings, and obtained 

 short periods of success ; at 12'' 35" I finally stopped. ]\Iy estimate 

 was thirty minutes' good running : the silver-grey received more 

 than his share ; there was a slip in the operation, and five drachms 

 of blood were lost between the rabbits ; so I did not care to let the 

 silver-grey bleed more. 



Oct. 6, 1870. — Silver-grey doe, I*, moderate size ; her blood-mate 

 was a Common grey doe, large. 



3'' 40"°, cross-circulation was established ; 3'' 44", excellent ; 

 3'' 50", excellent ; 3'' 55", excellent ; shortly after, something was 

 twisted or otherwise went wrong, and both stopped. I had a good 

 deal of trouble and but little further success. Ten drachms of blood 

 was lost between the rabbits (partly by leakage of the canulse). 



Oct. 7, 1871 . — Silver-grey doe, J *, moderate size ; her blood-mate 

 was a Yellow doe, dark about mouth, and also of mo- 



derate size. I afterwards became convinced she was simply a sandy 

 Himalaya. 



At 2" 5" established cross-circulation ; 2" 13", quite good ; 2" 20", 

 excellent ; 2" 25", excellent ; 2" 30", ditto ; 2" 35", ditto ; 2" 40", 

 ditto, then disconnected. An accident occurred at the end, by whicli 

 the silver-grey lost four drachms of blood. 



