VITAMIN A 279 



by fat-soluble vitamin deficiency," they mention "a nasal or bronchial 

 catarrh or even pulmonary infection with mucous or purulent exudate, 

 at times even resulting in hemorrhage. Animals thus afflicted in the 

 early stages of the disease sneeze and cough violently but later as the 

 inflammation becomes confined more to the lungs, the cough subsides, 

 and dyspnea becomes very pronounced with the slightest activity." 



In agreement with other observers, these authors have also noted 

 evidences of cutaneous malnutrition in animals deprived of vitamin A. 

 Such affections are more usual in rats over four months old and may 

 take the form of scabbiness of the tail or ears, sores or abnormal 

 growths on the nose, thin and bushy hair, and sore feet. 



They suggested that rats on diets suspected of being deficient in 

 vitamin A should be observed for all such symptoms as well as for eye 

 disease and failure of growth, and that judgment be based on the 

 sum total of indications (Steenbock, Sell and Buell, 1921). 



In the work of Sherman and Munsell (1925), in which rats 28 

 or 29 days of age were placed upon diets devoid of vitamin A, i.e., 

 the "negative controls" of experiments for the measurement of vitamin 

 A values of foods, it was found that 85 per cent of the cases developed 

 unmistakable eye disease before death and that distinct gatherings of 

 pus in one or more of the glands near the base of the tongue appeared 

 in 76 per cent of the cases. In this series of observations, therefore, 

 pus near the base of the tongue (found by careful search at autopsy) 

 was almost as constant a result of the vitamin A deficiency as was the 

 well-developed eye disease. Further observations in the same labora- 

 tory, however, lead to the belief that, with sufficient experience and 

 close observation, a very slight swelling of the eyelids and/or dis- 

 coloration at their junction may be detected after the depletion of 

 bodily reserves in practically all cases of rats kept from four weeks 

 of age upon vitamin-A-free food. (Personal communication from Dr. 

 F. L. MacLeod, 1927.) 



Sherman and Storms (1925) also found abscesses near the base 

 of the tongue in about three-fourths of the rats dying from vitamin 

 A deficiency; pus in the middle ear with about equal frequency; 

 sinusitis somewhat less frequently (in about one-half of the cases exam- 

 ined for this condition). These observers also found that when rats 

 of the same stock and previous nutritional history were placed upon 

 the same vitamin-A-free diet at different ages, the ophthalmia developed 

 in a larger proportion of the younger, and respiratory disease in a 

 larger proportion of the older animals. 



For the rats just mentioned, transferred from the same normal diet 



