ON OVARIOTOMY IN SOWS ; WITH OBSERVATIONS ON THE 

 aiAMMARY GLANDS AND THE INTERNAL GENITAL 

 ORGANS. 



By K. J. J. MACKENZIE, M.A.. and F. H. A. MARSHALL, Sc.D. 

 {School of Agriculture, Camhridge.) 



Part IV. 



In Part IIP of this series of coinnmnications we recorded that no 

 mammary fiigment could be found in the old sows that were examined 

 by us, and we suggested the possibihty that such pigment had previously 

 been present and had been destroyed or removed during the periods of 

 glandular activity. 



In the present note we record the results of four experiments which 

 were undertaken to test this hypothesis. 



Four sows of coloured varieties were taken, three being Large Blacks 

 and one a Berkshire. Each in turn was placed upon an operating table 

 and anaesthetised. Incisions were then made with a scalpel in the tissue 

 of two of the mammary glands, each cut being sufficiently deep and ex- 

 tensive to reveal the existence of mammary pigment if such were present 

 in the neighbourhood of the nipple. After the examination had been 

 completed, the incised tissue was stitched up and dressed with cotton 

 wool and collodion. The woimds healed by first intention. The four 

 sows were all operated upon on the same day, October 15th, 191.3. 



The following are the details of the experiments together with the 

 further history of each of the sows. 



(1) In a Large Black sow two mammary glands were examined for 

 pigment, namely those associated with the first (i.e., the most anterior) 

 nipple on the right side, and the third nipple on the left side. Black 

 pigment could readily be detected in each of the two glands. The sow 



1 Thia Jourtwl, Vol. VI. May, 1914, p. 182. 



