47 8 



THE QUARTERLY REVIEW OF BIOLOGY 



butter has been poured into shallow 

 dishes and then exposed to direct light and 

 bleached, vitamine A is destroyed. 



Oat straw is low in vitamine A but oat 

 hay dried out of direct sunlight appears to 

 retain the properties of fresh green oats. 

 It has been noted also that alfalfa hay 

 cured under caps and that cured in the 

 windrow with a comparatively distinct 

 difference in respect to time of exposure to 

 light and air have great differences in their 

 vitamine content. 



To describe all of the supposed physical 

 and chemical properties of the vitamines 

 would be a procedure too lengthy for the 

 purpose of this paper. It is of interest, 

 however, to note what chemical elements 

 are thought to play a part in the vitamine 

 molecule. In the case of vitamine B 

 analysis shows that it possibly contains 

 carbon, hydrogen, oxygen and nitrogen. 

 Many workers agree that the molecule 

 contains nitrogen. Some of the investi- 

 gators believe that vitamine A contains 

 carbon, hydrogen and nitrogen. At least 

 it has become quite firmly established that 

 nitrogen is present in the vitamine mole- 

 cule. 



In regard to one of the vitamines, Sher- 

 man and Smith say that partly from its 

 solubilities and its greater stability in 

 acid than in alkaline solution and partly 

 from the results of attempts at isolation, 

 it appeared probable at a relatively early 

 stage in the study of this vitamine that it 

 was a nitrogenous base very probably 

 related to the purines or pyrimidines. 

 It is perhaps a hopeful sign that later 

 evidence, both from attempts at its isola- 

 tion and from studies of its physiological 

 behavior, does not in the main contradict 

 the earlier indications. 



RELATION OF VITAMINES TO PLANT TISSUES 



In reviewing the relation of vitamines to 

 plant tissues, a logical starting point 



would be the seeds of plants. Seeds in 

 general are poor sources of vitamine A. 

 Furst, Chick and Hume have shown that 

 vitamine C is not present in dry seeds but is 

 produced during germination. Both dry 

 and germinated peas are deficient in 

 vitamine A. 



Just what part the vitamines play in 

 the germination of seeds is not definitely 

 known. They may be important in the 

 first stages of metabolism; perhaps they are 

 responsible for the onset of cell division. 

 They may exert some influence upon the 

 nucleus and protoplasm partition. 



In the case of animals, Sweboda by using 

 the yeast multiplication method finds that 

 the organs of internal secretion which are 

 of developmental importance are relatively 

 rich in vitamine B. The pituitary and 

 pineal glands are highest in vitamine con- 

 tent, and most of the other organs of 

 internal secretion — suprarenal, testis, 

 ovaries, and thyroid — contain about the 

 same amount of vitamine per gram of dried 

 tissue. He emphasizes the prominence 

 of vitamine B in those organs which are 

 important in connection with sex develop- 

 ment. 



Coward and Drummond are of the 

 opinion that the amount of vitamine A 

 present in etiolated shoots of peas is not 

 appreciably greater than that in the seed 

 from which it grew. Green shoots possess 

 a decidedly higher value as sources of 

 vitamine A than either the seeds from 

 which they sprang or the corresponding 

 etiolated shoots. 



According to Wilson it is generally 

 believed that the synthesis of vitamine A 

 takes place only in plants. The green 

 parts of plants appear to be among the 

 richest sources of the vitamine, whereas 

 seeds in general contain only traces of it. 

 It seems apparent therefore that the plant 

 must synthesize vitamine A found so 

 abundantly in its leaves. Since most 



