440 Dr. J. Hjort. Observations on the Distribution of 



DESCRIPTION OF PLATE. 



Figs. 1 to 7 inclusive, are all photographed with Spencer 4 mm. objective and 10 x 



eyepiece. 



Fig. 1. — Transverse section of Sakel hair, possibly accidentally pressed, and slightly 



swollen with sub-critical strength sulphuric acid ; showing radial (spiral) cracks. 

 Fig. 2. — Transverse section of same cotton as fig. 1. Section lightly pressed, then 



swollen with critical strength sulphuric acid ; showing growth rings. 

 Fig. 3. — Ordinary Sakel hair mounted in liquid paraffin, untreated. (Denham and 



Harland's method.) 

 Fig. 4. — Hair of Sakel cotton boiled in dilute HC1, and pressed. 

 Fig. 5. — Hair of Sakel cotton pressed heavily in 8 per cent, caustic soda. 

 Fig. 6. — Hair pressed in naphthamine blue. Spiral structure entirely due to pressure 



only. 



Fig. 7. — Hair of Sakel cotton pressed lightly in an adjusted mixture of cuprammonium 

 and soda. 



Figs. 8 and 9 are photographed with Spencer 16 mm. objective only, and 10 x eyepiece. 

 Fig. 8. — Hair swollen with calcium thiocyanate, showing double thread spiral. 

 Fig. 9. — Hair of Sakel cotton stained with iodine, but not otherwise treated ; showing 

 double pit spirals. 



Observations on the Distribution of Fat- Soluble Vitamines in 

 Marine Animals and Plants. 

 By Johan Hjort, D.Sc., For.Mem.K.S. 



(Received April 27, 1922.) 



(From the Biochemical Laboratory, Cambridge.) 



The Norwegian fishery investigators have for many years been engaged in 

 the study of the growth of fish, mainly the herring and the cod. By means 

 of microscopical study of the scales of the fish it has been possible to determine 

 the age of each individual fish, and by means of the assumption, which has 

 been verified within certain limits, that there is a proportion between the 

 length of the scale (4) and the length of the fish {If) {i.e., l s /l/= constant), 

 it has been possible to calculate the " growth curve " of the fish in different 

 years of its life, and in different seasons of the year. The results of this work,, 

 which have been summarised up to the year 1914,* proved that the growth 

 of the said fish in the Norwegian waters was confined to a few spring — and 

 summer — months only, and that the growth of the fish entirely ceases during 



* Johan Hjort, " Fluctuations in the Great Fisheries of Northern Europe," ' Rapports 

 et Proces-verbaux du Conseil International,' vol. 20, Copenhagen (1914). 



