622 METABOLISM 



abundance (the yeast and the orange juice), but the fat-soluble factor 

 is very low. Judged by its effect upon the growth curve of rats this factor 

 would appear to be absent from linseed oil. The latter, however, does con- 

 tain a trace which is sufficient to allow of an abnormal form of growth 

 in puppies. When animal fats, such as cod-liver oil or butter, are sub- 

 stituted for the linseed oil in the above, or a similar diet, rickets does 

 not occur. 



It will be seen in reference to the table on page 623 that there are 

 two main sources for the fat-soluble vitamin, (1) certain animal fats, 

 and (2) green leaves. It is particularly abundant in cream, butter, beef 

 fat, fish oils (particularly cod-liver oil and whale oil) and egg yolk. It 

 is absent or present only in traces in most vegetable oils, such as lin- 

 seed, olive, cotton-seed, but in some of them such as peanut oil it is 

 present in larger amounts. 



Its presence in green leaves stands out in contrast to its absence from 

 root vegetables. It is also present in certain cereals and pulses. 



The Antiscorbutic Vitamine. That scurvy is definitely due to the 

 absence from the dietary of some vitamin has been known in a general 

 way for a long time. It used to be very common among the crews in 

 the days of sailing ships, and nautical history records many interesting 

 observations, by captains and ship's surgeons, showing that it could be 

 prevented by adding certain fruits or the juices of fruits or vegetables 

 to the daily ration. Indeed lime juice became a regular part of the 

 mariner's ration. Great progress was made in the investigation of 

 the precise distribution and behavior of the antiscorbutic vitamin by 

 the discovery that guinea pigs develop the disease when all green stuff 

 is removed from the diet and the animals are fed on grains and water 

 or autoclaved milk. The symptoms appear in about 20 days, up to which 

 time if young animals are used, the growth curve continues. The symp- 

 toms and the postmortem findings are similar to those seen in man, (ten- 

 derness and swelling in the joints, swelling of the gums, loosening of 

 the teeth, tendency to hemorrhages and fractures of the bones). The 

 curve of growth declines, and the animal dies usually between the 30th 

 and 40th days. Important work is being done in the Lister Institute in 

 London to determine the minimal amounts of various foodstuffs that 

 are required in the scurvy diet to prevent the occurrence of the disease. 



Regarding distribution it may be said that this vitamin is found in 

 nature in all tissues which are actively undergoing metabolic change. 

 It is abundant in growing green leaves, in fruits and in germinating 

 seeds. But it is absent, or present only in traces, in dormant seeds, or 

 in plant tissues that have been dried. It is also present, though less 

 abundant in fresh animal tissues and in milk. Although potatoes do 

 not contain much of this vitamin, a diet composed mainly of them is 



