Fat-Soluble Vitamines in Marine Animals and Plants. 443 



for some reason they were unsatisfactory for nutritional experiments and gave 

 ambiguous results. Other methods had therefore to be applied. 



In the spring of 1922 material was, therefore, collected partly in a fresh or 

 sterilized condition, partly in alcohol. In co-operation with my assistant, 

 Dr. Axel Palmgren, a different method was developed for the extraction of 

 the oils. 



The fresh material was first minced, then dried in thin layers on filter 

 paper in the constant- temperature room of the laboratory (at 37°). The 

 dried substance proved in all experiments as effective as fresh substance,, 

 and it could therefore be applied for the purpose of extraction by acetone or 

 benzene. The filtrates (from three to four extractions) were evaporated in 

 vacuo, the last part of the solvent evaporated off in a water bath at 90°-100° 

 in a high vacuum for 15 minutes, till the remaining oil no longer smelt of 

 benzene. The oil was then dissolved in olive oil, and the mixture given to 

 rats by a counted number of drops, 100 drops making 3 c.c. of oil. At 

 a specific gravity of - 9, one drop would then have a weight of 2-7/100, or 

 27 mgrm. If one part of the oil had been dissolved in seven parts of olive 

 oil, eight or sixteen drops were given to each rat daily, in order to give the 

 rat one or two drops of the oil under experiment. In the following " one 

 drop " means one drop of the oil under experiment. The oil was not mixed 

 with the food, but administered by means of a pipette kept just over the 

 mouth of the rat, which was laid on its back in the left hand. This method 

 of feeding was recommended to me by Prof. E. Poulsson, of the University of 

 Christiania. 



The experiments are all of a preliminarjr character, and had mainly the 

 purpose of exploring the distribution of fat-soluble vitamines, for future 

 more detailed and more quantitative studies. In spite of their preliminary 

 character, it has been thought useful to publish the following observations,, 

 as they may stimulate other workers to investigate this field. 



Marine Plants. 



As a preliminary investigation, it seemed to me of interest to try some 

 green algae as representatives of the vegetation along the shore and some 

 samples of the first growth of diatoms in the coast waters during spring. 



Green atyoc ( Ulva lactuca and Codium tomentosum) were kindly collected for 

 me at the Marine Biological Station at Port Erin by H. H. Thomas and 

 S. H. Wadham, of the Botany School of Cambridge. The algae were brought 

 to us in fresh condition, and given partly in fresh and partly in dried 

 condition to rats which for some time had been on a diet free from 

 fat-soluble vitamines, but containing vitamine B. and other essentials. The 



