62  Comparative  Composition  of  Milks.      { AFebiuaryPi908m* 
While  there  is  a  marked  difference  in  the  fat-percentage  of  the 
milks  of  different  breeds  of  cows,  and  in  individuals  of  the  same 
breed,  there  is  a  fairly  uniform  difference  in  the  averages  of  several 
individuals.  "  It  is  largely  owing  to  this  influence  that  we  find  the 
milk  of  one  country  differing  from  that  of  another,  or  the  milk  of 
one  section  of  the  country  differing  from  that  of  another  section. 
For  example,  the  average  amount  of  fat  in  milk  in  Germany  and 
Holland  is  fully  one-half  per  cent,  lower  than  in  this  country,  be- 
cause the  prevailing  breeds  there  are  those  producing  milk  compar- 
atively low  in  fat."  (Modern  Methods  of  Testing  Milk  and  Milk 
Products,  L.  L.  VanSlyke,  1907,  6.) 
COMPARATIVE  COMPOSITION  OF  HUMAN  MILK  AND  COWS'  MILK 
(At  Intermediate  Period  of  Lactation) 
Human  Milk 
Glycerides  of  the  non-volatile 
fatty  acids  
Olein  2.00 
Palmitin  ] 
Stearin 
Dioxystearin  j-2.00 
Laurin 
.  Myristin 
Glycerides  of  the  volatile  fatty  \  ^1^.^ 
acids j  Caprylin 
[  Caprin 
\  trace 
Proteids 
Casein 
Albumin 
Opalisin 
j  Globulin 
j  Galactin 
I  Fibrin 
0.75 
1.00 
trace 
trace 
Milk  Sugar  
Citric  Acid  (as  Citrates) 
Salts  
4.00 
(Fat) 
1.75 
 6.50 
(0.05)  trace 
 0.25 
Total  Solids  12.50 
Water  87,50 
100.00 
Cows'  Milk 
1.40 
2.25 
0.35 
3.001 
0.50 
trace 
trace 
trace 
4.00 
(Fat) 
r3.50 
4.50 
(0.125)  trace 
0.75 
12.75 
87.25 
100.00 
American  pediatrists  generally  accept  the  following  standard  of 
percentages  for  human  milk:  Fat,  3  to  5  per  cent. ;  proteids,  I  to  2 
per  cent.,  and  sugar,  6  to  7  per  cent.,  the  average  being,  fat,  4  per 
cent.;  proteids,  1-5  per  cent.,  and  sugar,  7  per  cent.  The  data,  sub- 
mitted, however,  would  seem  to  indicate  that,  generally,  at  the  inter- 
