THE ANIMAL MACHINE 23 



great volume of blood supply furnished the uterus and 

 foetus is diverted to the mammary apparatus, stimulating 

 it to the maximum of functional capacity, as noted in the 

 fresh cow. The first material secreted by the udder differs 

 both physically and chemically from milk, being thick 

 and yellowisli in appearance and possessed of special pur- 

 gative properties designed to remove the foecal matter, 

 meconium, that has accumulated during foetal develop- 

 ment, as the first operation of the new-born digestive 

 apparatus. 



Pathology 



28. Abnormal structure impairs function. — The rela- 

 tion between structure and function is intimate and re- 

 ciprocal. Functional limitations are determined by the 

 structure, while the development of the structure itself is, 

 in a measure, responsive to the activity of its function. 

 Carrying one's arm in a sling continuously will cause 

 such complete atrophy or wasting of the part as to seri- 

 ously impair its usefulness, while the heart of the athlete 

 undergoes hypertrophy, or an over-development, in an 

 effort to meet the excessive demands made upon it. The 

 removal of one kidney may induce a compensatory hyper- 

 trophy of the other one. An active secreting mammary 

 gland is " dried off " by arresting its functional stimulus, 

 the milking process, while the rudimentary gland of the 

 male, even, may be rendered capable of some functional 

 activity by persistent stimulation. 



It is obvious, therefore, that but a slight structural 

 defect may seriously impair the functional capacity of the 

 part or the individual. It is not sufficient simply to 

 detect the presence of an existing defect or abnormality; 

 its true significance, in interfering with the function of 

 the part, must be foretold. 



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