22 8 DISCOVERY REPORTS 



single district, by collecting ovaries from the Blue females caught by pelagic whalers it 

 would be possible to obtain information from all the areas which are commonly worked. 

 In 1933-4 a small collection was made through the courtesy of the Southern Whaling 

 and Sealing Company, in the season of 1934-5 eight British and Norwegian factory ships 

 contributed collections of ovaries, and in 1935-6 ten factories co-operated. The collectors 

 have in most cases kept records of the length and sexual condition of the whale from 

 which the ovaries were taken, which information greatly enhanced the value of the 

 collections. 



For the success of this scheme thanks are due to the individual whaling companies 

 and in particular to the secretary of the Norwegian Whaling Association, the late Sigurd 

 Risting, and to his successor, Mr Harald B. Paulsen, without whose energetic co- 

 operation only minor success could have been achieved. 



The ovaries were taken from Blue females over 77 ft. in length while the carcasses 

 were being dismembered on the decks of the factory ships. Each pair was tied securely 

 with twine and a numbered metal tab was attached. (Cardboard labels were used in the 

 small collection made in 1933-4 but these were torn from the ovaries during transit, 

 rendering correlation of length with the condition of the ovaries impossible.) The length 

 of each whale was recorded against the number allotted to the ovaries, together with the 

 date of capture and the position of the ship on that date. The ovaries were stored in 

 empty salt-meat casks filled with sea water, to which in 1934 was added half a litre of 

 40 per cent formalin. In 1935, after the corpora lutea of pregnancy had become im- 

 portant through the discovery of significant quantities of progestin therein (Callow, 

 Laurie, and Parkes, 1935), a less destructive preservative was desired and salt was used. 

 Eight pounds of commercial rock salt were added to the sea water in each barrel to make 

 a saturated solution. This latter agent proved unsatisfactory both for the preservation of 

 the ovaries as a whole and for the retention of the hormone, and many pairs of ovaries 

 had to be thrown away. The barrels were shipped home as opportunity arose and arrived 

 in London from three to six months after they had been filled. 



Those ovaries which were not too decomposed were examined at the Natural History 

 Museum, and, while distinctly offensive to smell and handle, they were with the excep- 

 tions mentioned good enough for the identification of corpora lutea, for which the only 

 equipment required was a pair of rubber gloves and a carving knife. I must here 

 gratefully record the forbearance and fortitude of the authorities and other workers in 

 the Natural History Museum in allowing me to carry on this malodorous work on the 

 premises. After examination, the corpora lutea of pregnancy were given to the Medical 

 Research Council for research into the progestin content, and the rest of the ovaries were 

 incinerated by the Sanitary Authority. 



What follows is divided into three main parts: first, general biological notes chiefly 

 from personal observations linking up pelagic Blue whales with what is known about 

 South Georgia Blues, and breaking some new ground; second, consideration of the 

 material and statistics supplied by the collectors of ovaries, and deductions as to the age 

 of Blue females at maturity, the rate of ovulation, and the span of life ; third, the applica- 



