534 THE TOCOPHEROLS 



Lesions of the cerebellum and cerebrum resulting from vitamin E defi- 

 ciency in birds appear to be secondary to vascular changes and, for that 

 reason, are discussed in the following section. 



6. Vascular System 



a. Chicks 



Most of the lesions ol)served in vitamin E-deficiont chicks appear to be 

 the result of alterations in the peripheral vascular system, especially the 

 capillary bed. Like the skeletal muscle lesions of the duck, the chick, and 

 the pheasant"' •*■'■ ^*- ^"^ and gizzard necrosis of the turkey and the 

 chick,*^'' ^^' ■*'" referred to previously, these manifestations are rarely seen 

 in chicks after the second month of life. Since they occur spontaneously 

 in the field with variable fre(iuency,**'' ^""' '"- they are of economic as well 

 as academic importance. 



(1) Emhnjonic M orialiti) . According to Adamstone,'"^ inadequate vitamin 

 E in the chick egg results in embryonic death at about the fourth d-dy of 

 incubation, due to disintegration of blood vessels of the blastoderm, hemor- 

 rhage into the coelom and exocoelom, and cellular proliferations in the blas- 

 toderm which interi'upt the vitelline circulation. If this critical period is 

 passed, there may be spontaneous rupture of vasculai- channels at ^'ari()us 

 sites within the embryo, usually associated with clusters of pycnotic his- 

 tiocyte-like cells at the points of extravasation. Whether these cells arc 

 responsil)le for the vascular rupture or represent a protective reaction at 

 the site of injury has not been satisfactorily established. 



(2) Exudative Diathesis. Chicks I'eared from hatching on low-E diets 

 usually exhibit a state of exudative diathesis or of nutiitional encephalo- 

 malacia, or sometim(>s l^oth, during the first two months of life. The two 

 manifestations ap])ear to be secondary to dysfunctions of the capillary 

 bed, sometimes regress spontaneously, and are influenced considerably by 

 variations in fats and other dietary ('om{)onents. 



J^Audative diathesis, as described by Dam and ( ihuind,'"' is characterized 

 grossly by the appearance of large patches of subcutaneous edema on the 

 breast and abdomen, and l(\ss fre(iuently on the neck, legs, or wings. These 

 represent local subcutaneous and interfascial accumulations of a plasm-like 

 fluid frequently tinged greenish by decomposed hemoglobin. The affected 

 tissues show edema, hypei'emia, and increased permeability of the capil- 

 laries as indicated by increased absorption of intraN'enously injected Trypan 

 blue. The subcutaneous tissue at the site of old lesions i-etains a buff color 



'"2 F. Ji. Adamstone, ./. Morphol. 52, -17 (IIKU); Arch. I'ulhol. 31. (i22 (1941). 

 io» H. Dam aiul J. Cilaviiid, Satiirv 143, SlO (1()3!>); Skaiul . .\rrli. I'hiisiol. 82, 299 

 (1939). 



