OIL-BEARING SEEDS AND BY-PRODUCTS 139 



from the meal, manufacturers and feed control officials have agreed on 

 the following classification : 



Choice cottonseed meal must be perfectly sound and sweet in odor, yellow, 

 not brown or reddish, free from excess of lint, and must contain at least 41 

 per ct. of crude protein. 



Prime cottonseed meal must be of sweet odor, reasonably bright in color, and 

 must contain at least 38.6 per ct. of crude protein. 



Good cottonseed meal must be of sweet odor, reasonably bright in color, and 

 must contain at least 36 per ct. of crude protein. 



Cottonseed feed is a mixture of cottonseed meal and cottonseed hulls, con- 

 taining less than 36 per ct. crude protein. 



Owing to its wide variation in composition, cottonseed meal should 

 be purchased on guarantee whenever possible. 



Cottonseed feed. — On northern markets cottonseed feed, consisting 

 largely of hulls, is often sold for only a little less than choice cotton- 

 seed meal. Yet average cottonseed feed contains but 24.5 per ct. crude 

 protein, and is thus worth only 60 per ct. as much as choice cottonseed 

 meal. Since it is impossible to tell finely ground cottonseed feed from 

 the best cottonseed meal by its appearance alone, the wise feeder will 

 always buy cottonseed meal from reliable dealers. 



Cold-pressed cottonseed cake. — Cold-pressed cottonseed cake, or 

 "caddo" cake, is produced by subjecting the entire uncrushed, 

 unheated seed to great pressure. In this cake there is a larger propor- 

 tion of hull to meal than in the usual cottonseed meal, with correspond- 

 ingly lower feeding value. This product is usually sold in nut or pea 

 size but is sometimes ground to a meal. The crude-protein content of 

 cold-pressed cake is a reliable guide to its feeding value. 



The poison of cotton seed. — Experience and scientific trials unite in 

 showing that cotton seed or cottonseed cake or meal is not always a 

 safe feed. After about 100 days steers closely confined and heavily 

 fed on meal often show a staggering gait, some become blind, and death 

 frequently ends their distress. Cottonseed meal is most poisonous to 

 swine. Pigs getting as much as one-third of their concentrates in the 

 form of cottonseed meal thrive at first, but after a few weeks they 

 become sick and may die. 



During the past 20 years numerous attempts have been made to find 

 the cause of the poisonous effect, and many different reasons have been 

 advanced by scientists. Further work has, however, failed to prove 

 that the fatal effect is due to any of the causes assigned. Recently, 

 Withers of the North Carolina Station ^ has attributed the poisonous 

 quality to a substance called "gossypol, " which is formed in certain 

 cells of the seed. It is to be hoped that further work may reveal 



2 Jour. Agr. Res., 5, 1915, pp. 261-88. 



