448 Fat-Soluble Vitamines in Marine Animals and Plants. 



promoting factors. Drying of fish and fish products plays a great role in the 

 fishing industry of different countries, and it is therefore of practical value 

 to know that the process does not deprive the products of these valuable 

 qualities. 



Extraction of the powdered dry roe by means of benzene produced a clear 

 but thick oil, different from the wax, which was obtained by extraction with 

 alcohol and ether. The effect of one drop daily of this oil is illustrated by 

 the curves on fig. 13. In one rat, which had developed the eye disease 

 (keratomalacia) characteristic of cases upon a diet deficient in the fat-soluble 

 vitamine, this disease was cured after the addition of the oil of the roe, but 

 this rat did not later on show any increase in its growth. 

 100 



90 

 80 

 70 

 60 

 50 

 40 



5 10 15 20 25 30 35 40 45 



Fig. 13. — Benzene extract of dried cod roe, 

 1 drop per day. 



The fact that oils extracted from marine plants have been proved to have a 

 very strong effect on the growth of rats fed on a diet deficient in fat-soluble 

 vitamines seems to indicate the working hypothesis that fat-soluble vitamines 

 in the sea arise in plants in a similar way to that proved to be the case in 

 plants on land. It seems, further, natural to assume that all marine animals, 

 directly or indirectly, obtain these substances from the plants, and that the 

 marine animals, like other animals studied, are unable to synthesise these 

 substances. An important programme for future work seems then to suggest 

 itself, viz., to determine the quantitative distribution of fat-soluble vitamines 

 in different types, and in them during different seasons of the year. It may 

 be possible by such studies to approach the important problems of the 

 influence of the food of animals on that periodicity in their growth which is 

 so remarkable in Northern waters. The present investigations seem to 

 indicate the problem to ascertain how far the production of fats and fat- 

 soluble vitamines in the plants during spring and early summer months will 

 have to be regarded as the store on the magnitude of which the growth of 

 animals is dependent in Northern latitudes. In Southern latitudes the 



