niKTIsTfl DKFKlKiNCV. 293 



protein. Wheat has a com])aratively hiij^h |?r()teiii CDiitcnt, and by 

 siii)|)lenienting- mineral dehciencv with inorganic saUs a (het may 

 be rea(hly constructed which at least fulfils the usual text-book 

 conditions of dietetic sufficiency. Yet within the last few years 

 several ])apers have appeared in which cx]ierimental evidence 

 is adduced to show that an exclusive wheat diet is inade(|uate 

 for the normal growth and re])roduction of animals. Mart. Mc- 

 Colhun. and Steenbock maintain that wheat alone does not allo^^ 

 of normal rej^-oduction in herl)iv()ra, l)Ut leads to weak and 

 under-sized otts])ring, while an addition of maize to the ration 

 allows of a normal reproductive cycle. 



As an illustration of the eiifect on cjruzvth of a diet restricted 

 to the products of the wheat grain, the following figures of Mart 

 and McCollum* may be cited, parallel data for maize being given 

 for comparison. 



Diet. 

 Ratiijii II. Ration IV. 



Wheat imal 97.} per cent. .Maize meal 70 per cent. 



Wheat .yluteii 2} per cent, (ihiten feed 30 per cent. 



jihis salts. plus salts. 



Weight (if Weight of 



Pig No. 7. Pig No. 3. 

 1 )ate. Ihs. . . lbs. 



Al arch nth 44 49 



A)jril _'_>n(l 68 63 



June 1 7th 82 <Sj 



July 8th 89 So 



September 30th Q2 \A~ 



October 28th 86 17' 



In l)()th cases the i)r(jtein content of the ration was a> high 

 as 14 ])er cent, (jrowth on the maize products was normal, but 

 the growth failure on the wheat ration was most marked. No com- 

 plete explanation of the difference can be given (the authors 

 suggest "toxity in wheat kernel"), but in the experiments cited 

 the substitution of 2y2 per cent, of casein for the 2j/ per cent, of 

 wheat gluten sufficed to induce normal growth. 



( )sb(^rne and Mendel, in 1914. showed that if ])tirc giiadin — 

 i.e., the principal protein of wheat — be fed to yoimg rats as exclu- 

 sive ])rotein in the diet, growth is restricted irrespective of the 

 amount given. They have also shown that rats do not grow on 

 a diet consisting of certain ])i:re isolated ])roteins along with 

 -Starch, lard, and ])roteiu-free milk. l\. however, the lard is 

 re])laced by butter, or if a little whole milk be added to the (het. 

 the symptoms of ill-health (diarrlKea) disa])pear, and n(;rmal 

 growth is maiiuained. 



Other investigators have obtained analogous results, certain of 

 which will be discussed presentlw 



If we accept the experimental evidence as sound, we have 

 here two types of deficiency suggested : — 



((7) A deficiency arising from the kind or the (|Ualit\- of 

 the protein irrespective of its (|uantity ; 



* Journal of Biological Cheiiiisfry. Xoveml)cr, 1014. 



