90 SECEETION. 



globules, of great refractive power, held in suspension in a 

 clear fluid. These are known under the name of milk- 

 globules, and are composed of margarine, oleine, and a fatty 

 matter, peculiar to milk, called butyrine. In human milk 

 the particles are perfectly spherical ; but in cow's milk they 

 are often polyhedric from mutual compression. This differ- 

 ence is due to the softer consistence of the butter in human 

 milk, the globules containing a much larger proportion of 

 oleine ; and if cow's milk be warmed, the particles also as- 

 sume a spherical form. 



The human milk-globules measure from as ^ o0 to I2 1 go 

 of an inch in diameter. They are usually distinct from each 

 other, but may occasionally become collected into groups 

 without indicating any thing abnormal. In a perfectly nor- 

 mal condition of the glands, when the lacteal secretion has 

 become fully established, the milk contains nothing but a 

 clear fluid with these globules in suspension. The propor- 

 tion of fatty matter in the milk is from twenty-five to 

 forty-eight parts per thousand, and this gives an idea of the 

 proportion of globules which are seen on microscopical ex- 

 amination. 



There has been a great deal of discussiqn with regard to 

 the anatomical constitution of the milk-globules. In many 

 late works it is stated that they are true anatomical ele- 

 ments, composed of fatty matters surrounded by an albumin- 

 oid membrane; but other writers assume that the fat is 

 merely in the form of an emulsion, and is simply divided 

 into globules and held in suspension, like the fatty particles 

 of the chyle. ~No one, however, has assumed to have seen 

 the investing membrane of the milk-globules, and its exist- 

 ence is only inferred from the behavior of these little par- 

 ticles in the presence of certain reagents. 



It is unnecessary to review in detail the numerous opin- 

 ions that have been advanced on this subject. As far as 

 can be ascertained by simple examination, even with the 

 highest magnifying powers., the globules appear perfectly 



