144 THE PROTEIN ELEMENT IN NUTRITION 



These Canadian observations have been corroborated by the 

 work of Skinner* in Indiana, who fed hogs on a low protein 

 dietary of Indian meal. This diet caused impairment of the 

 digestive capacity, which became more apparent the longer the 

 diet was continued. It resulted in " poor appetites, light bone, 

 deficient development in valuable portions of the carcass, and 

 a general state of unthrift, as shown by the hair, skin, and 

 hungry look of the animals." The addition of one-sixth of the 

 amount of the ration in materials rich in protein resulted in 

 normal growth and a healthy condition. 



A similar series of experiments have been carried out by Pro- 

 fessor Haecker on herbivorous animals. Benedict, quoting 

 from unpublished results, remarks that herbivora being accus- 

 tomed to diets relatively low in protein, a further decrease 

 would be expected to be accompanied by less marked disturb- 

 ances, which might take a considerable time to develop, than 

 in the case of carnivora or omnivora. 



Haecker' s investigations were carried out with the view of 

 determining, from an economical standpoint, to what extent 

 the amount of protein could be decreased with safety and 

 economy . 



Two groups of cows of ten in each group were fed for a period 

 of three years, one group on a diet containing the normal pro- 

 portion of protein, the other on a much lower protein ration. 

 No ill-effects appear to have been noticeable for some time, 

 although the second group had lost somewhat in weight. During 

 the first part of the third winter both groups did well, but by 

 January the cows receiving the low protein dietary began to 

 fail. By March 13 it became absolutely necessary to increase 

 the proportion of protein, as the cows had become very thin in 

 flesh, and their coats dry and harsh a well-recognized indication 

 of under-nutrition. 



It is particularly worthy of attention that the effects of a 

 low protein dietary on the pigs and cows was very gradual, but, 

 nevertheless, led in time to a general deterioration of health. 

 The importance of this in appraising the merits of dietaries low 

 in protein for man cannot be over-estimated. It demonstrates 

 clearly that experiments with diets of low protein content, to 

 be conclusive, should last for years, as the beneficial effects of 

 previous high protein feeding may be persistent and prolonged. 



* Skinner, Indiana Agriculture Experimental Station, Bulletin No. 108. 



