178 Agricultural Experiment Station, Ithaca, N. T. 



erned far more by the amount of nitrogen in the food than by the total 

 amount of dry matter which it contains. It will be noticed that with 

 one exception (ewes in experiment No. 6) the lowest in nitrogen con- 

 sumption drank the least water, the next higher in nitrogen consump- 

 tion was the next higher in water drank, the third in nitrogen consump- 

 tion also was third in the amount of water drank and this order was 

 maintained throughout the remaining experiments. 



The variation in the amount of water drank is controlled more by the 

 secretion of urine than by the amount of total dry matter consumed in 

 the food. Tliis fact has been noted by experimenters in stock feeding 

 and was published by Lawes and Gilbert in " Supplementary Report on 

 the Experiments on the Feeding of Sheep," volume II, page 19, which 

 says: "It may be interesting to remark that the proportion of water 

 drank to the food consumed was the greatest * * * where the 

 amount of nitrogenous substances was the greatest. This is quite con- 

 sistent with the observation ©f ourselves and others, that under other- 

 wise equal circumstances the larger the amount of nitrogenous constitu- 

 ents the greater will be the amount of urea passed off in the urine and 

 that, as has recently been shown, the greater the elimination of urea 

 the greater will be the demand on the system for water." 



Halliburton gives practically the same law governing the secretion of 

 urea when he says:* " The quantity of ui-ea in urine varies a good deal, 

 the chief cause of variation being the amount of proteid (nitrogenous) 

 food digested. In a man who is in a state of equilibrium and on an 

 ordinary mixed diet the quantity of urea secreted daily is between 

 twenty-five and forty grams. On a diet poor in proteids it may sink 

 to fifteen or twenty grams^ and on a diet rich in proteids it may rise to 

 100 grams per diem." 



It does not follow that where nitrogenous food forms a large portion 

 of the ration that the manure will contain a much larger per cent of 

 nitrogen than if the food were only moderately rich in nitrogenous con- 

 stituents, for in ordinary practice the increased secretion of urine will 

 demand a greater supply of bedding which would decrease the percent- 

 age of nitrogen in the manure, so that the proportion of nitrogen to 

 the weight of manure would not be increased while the total nitrogen 

 voided would be in great excess of that voided from less nitrogenous 

 food. 



Mcperiments with calves. — Two high grade Holstein calves were 

 placed on the manure cans as described in the experiments with sheep. 

 The calves were bedded liberally with fine cut, clean, white straw. 



* Chemical Physiology on Pathology, p. 788. 



