Producing Large Yield. 267 



things being equal, than those that are less round in form. 



The flat-side form is developed on comparatively level 

 surfaces, where there is but little side-strain on the mus- 

 cles, while the round form is developed where the surfaces 

 are undulating ; the reasons for which are given in another 

 place,* as we have here to trace out several of the leading 

 influences that have established larger yield in the Hol- 

 steins and similar Netherland cows. 



First, the atmosphere of the Netherlands is very moist, 

 containing much watery vapor, the natural moisture of the 

 air entering into the composition of all roots and grasses 

 grown there, in a larger degree than takes place in dry 

 climates. In this way the feed is made more succulent, 

 as well as more bulky, than the more concentrated feed 

 produced in dry climates ; thus leading to a larger bulk of 

 blood, in supplying an equal extent of nutrition in their 

 feed to the cows. For this reason, the bulk of blood 

 formed, and the bulk of yield derived from it, is greater 

 in cows raised in moist climates, than in those raised in 

 dry climates. This is one source of greater quantity in 

 their yield. 



The greater amount of watery vapor in the atmosphere, 

 together with the greater amount of moisture in the soil, 

 also causes a much larger proportion of moisture, probably 

 amounting to several thousand gallons a year, to enter the 

 blood of a cow by way of the lungs, as watery vapor in the 

 air she breathes ; which is another source of increase in 

 bulk of blood, and one that is much less available in dry 

 climates. Both those influences have their share in making 

 up bulk in the yield of cows in moist climates. There be- 

 ing a larger bulk of blood, to nutritive value, the excess 

 of bulk from excess of moisture leads to increase in the 

 size of the arteries, and the total quantity of blood enter- 

 ing the tissues, and in the vessels of the entire circulation, 



* In remarks on California Short-borns. 



