VIII. EFFECTS OF DEFICIENCY IN ANIMALS 289 



ing alteration in permeability. However, it is also possible that leakage of 

 the capillaries is explainalile by swelling of the walls without marked molec- 

 ular disorientation. 



(2) Arteries and Veins. Thin walls in l)oth arteries and veins have been 

 reported in scurvy;^- '°^ there is also some evidence of lytic processes result- 

 ing in disintegration of the vessel walls.^^ Hemorrhages occur frequently, 

 i)ut a hyperemic condition is often mistaken for a hemorrhage.*** The partial 

 diappearance of the collagen fibrils is considered to be an important factor 

 in the pathogenesis of the hemorrhages.'' In addition to this direct weakening 

 of the \'e.ssel walls there is an effect caused by shrinking of the cells of the 

 tissues which reduces the outer support for the atrophic vessel walls. With- 

 out this support the pressure from the inside presumably must have a still 

 greater effect.'^ 



(3) Blood Pressure. Selezeneva'-' found a great reduction in the response 

 to intravenous injections of epinephrine in animals deficient in vitamin C. 

 On the other hand, Lee and Holze,'-^ using larger doses of the hormone, 

 found no difference in blood pressure between the scorbutic and normal 

 groups or in the ability to respond in pressor manner to injections of epi- 

 nephrine. As compared to the normal control animals the scorl)utic animals 

 had a definitely lessened ability to withstand loss of blood. 



b. Blood 



The somew'hat divergent reports of the blood picture in scurvy by differ- 

 ent in\'estigators are probably to be ascribed chiefly to differences in ex- 

 perimental conditions, such as nature of the diet, age of the animals, and 

 degree of advancement of the scorbutic condition. Very young animals 

 often fail to show definite blood changes because they die from scurv}'' too 

 quickly for anemias to develop.^'" The extent of hemorrhage is probably of 

 special significance in influencing the blood picture. Although knowledge 

 of the dietary requirements of the guinea pig is far from complete, some of 

 the earlier studies made on the blood could profitably be reinvestigated in 

 the light of the present known facts. Undoubtedly some of the studies have 

 been made with animals maintained on diets deficient in factors other than 

 ascorbic acid. 



(1) Volume. Harman and Kordisch'-^- '" observed an apparent change 

 in blood peripheral volimie during the progress of scurv3^ In the early stages 

 of the deficiency, blood could easily be obtained from any peripheral vessel 



1" A. A. Selezeneva, Proc. Set. Inst. Vitamin Research (U.S.S.R.) 3, 205 (1941). 



1" R. E. Lee and E. A. Holze, Proc. Soc. Exptl. Biol. Med. 76, 325 (1951). 



>" H. C. S. Aron, J. Nutrition 18, 375 (1939). 



'^^ M. T. Harman and M. S. Kordisch, Trans. Kansas Acad. Sci. 47, 367 (1945). 



>" M. T. Harman, Trans. Kansas Acad. Sci. 53, 319 (1950). 



