No abstract

TWENTY-SEVEN PIQURES IKTRODUCTIONRichardson and Hogan ('46) observed that about 2% of the infant rats produced by darns fed a synthetic type ration were hydrocephalic and showed that the abnormality could be prevented by including a liver extract in the diet. O'Dcll, Whitley a i d Hogan ( '48) found that hydrocephalus among tho offspring was largely prevented when folic acid was added to the diet. Later, O'Dell, Tl'hitley and Hogan ('51) showed that a much higher incidence of hydrocephalus, approximately 20% of the offspring, occurred when the dams consumed an all vegetable diet deficient in vitamin B12. The addition of vitamin B,, to the diet completely prevented the occurrence of hydrocephalus. More recent evidence (unpublished) has shown that an incidence of hydrocephalus of the order of 207. may be induced in the offspring of dams fed a folic acid antagonist (0.05% of crude methylfolic acid) even though vitamin B,, is present in adequate amounts. Nelson, Asling and Evans ('52) have used this same antagonist at a level

No abstract

No abstract

The guinea pig is highly susceptible to soft tissue calcifi cation. Wulzen and Bahrs ('41) first reported a stiffness syn drome which has heen studied in detail and reviewed by van Wagtendonk and Wulzen ('50). The syndrome was charac terized by stiff joints and by extensive soft tissue calcification and necrosis. A similar syndrome was reported by Hogan et al. ('50, '54) in guinea pigs that consumed excess phos phorus. Smith et al. ('49) also observed metastatic calcifica tion when certain diets were fed for long periods. Roine et al. ('49) pointed out that for maximum growth the guinea pig has a high requirement for potassium and magnesium. House and Hogan ('55) observed that high levels of these elements protect guinea pigs from soft tissue calci fication. Magnesium deficiency has been implicated in meta static calcification in other species including the calf (Moore et al., '38), the cotton rat (Constant and Phillips, '54) and the white rat (Tufts and Greenberg, '38). The rabbit has a high requirement for potassium (Hove and Herndon, '55), but part of the requirement can be met by other cations (Wooley and Michelson, '54). The high cation requirement of guinea pigs is partly due to their inability to conserve fixed bases by excreting ammonia in the urine (O'Dell et al., '56). Gum arabic has been reported to be superior to celluflour as a