STERILIZED MILK. 
A REPORT OF SOME EXPERIMENTS MADE TO DETERMINE THE PROPER 
MANNER OF HOII.ING AND PRESERVING MILK 
FOR THE USE OF INFANTS.* 
BY AUGUSTUS CAILLE, M.D., NEW YORK, 
VISITING PHYSICIAN TO THE GERMAN HOSPITAL AND TO THE GERMAN DISPENSARY 
(DISEASES OF children). 
In Nos. 15 and 16 of the Miinchner Medizinische IVochenschrift (1886), 
Dr. Soxhlet reports his experience in preparing and feeding sterilized milk, 
and describes an apparatus by means of which the procedure can be practi- 
cally carried out in every household. This communication does not seem 
to have attracted attention on this side of the Atlantic, for I have never 
heard it spoken of, and have never seen a press notice of the subject in any 
of our journals. 
During my vacation last summer I met at Wurzburg, Bavaria, a very 
reputable colleague who is particularly interested in Padiatrics, and, in the 
course of conversation, he made mention of sterilized milk, expressed his 
surprise that little attention was paid to this matter in the United States, 
and spoke very highly from personal experience of Soxhlet’s apparatus. 
The gentleman was kind enough to introduce me to the parents of two of 
his little patients who were fed on sterilized milk, and I ascertained, by 
directly questioning the mothers, that they had no difficulty whatsoever in 
manipulating the milk according to directions. 
Subsequently I met at Carlsbad. Bohemia, another colleague, who con- 
firmed the statements of my friend at Wurzburg, and who assured me that 
he frequently ordered the sterilizing apparatus in his practice. These state- 
ments induced me to import a set of Soxhlet’s utensils, with a view of care- 
fully investigating the subject from a practical standpoint. 
Before giving the results of my observations I will refer briefly to the 
theoretical part of our subject. The investigations of Lister show that the 
milk in the cow’s udder is aseptic, and the same is true of nnlk within the 
human female breast, according to Escherich. 
Soxhlet, in his article, says: “ During the process of milking, particles 
of manure and other forms of dirt get into the milk, and, during transporta- 
tion and general handling, fermentation sets in, so that much of our milk is 
really unfit for consumption before it gets into the hands of the consumer— 
i. <?., into the stomachs of infants and children. Mothers’ milk, on the con- 
trary, is taken directly, and would, undoubtedly, be equally contaminated 
and frequently injurious to infants if it suffered the same manipulation as 
cows’ milk," and he quotes the well-known fact that calves fed on milk from 
a trough frequently suffer from diarrhoea. 
Dr. Soxhlet does not fully consider the difference in composition be- 
tween cows’ milk and human milk, but otherwise his reasoning appears to 
me to be sound. 
♦ Read at the meeting of the Paediatric Section of the N. Y. Acad. Medicine, Feh. yg. He proposes, therefore, to sterilize all milk for children’s use, and his 
method is as follows : 
Description of Sterilizing Utensils. 
1. Twenty well-annealed 5-oz. bottles, with stoppers of rubber and glass 
combined. The rubber stopper fits well into the neck of the bottle and is 
perforated, in order to admit a slender glass stopper. 
2. Wooden stand with zinc dripping pan for inverted reserve bottles, 
and provided with a drawer for extra corks, nipples, etc. 
3. A tin or galvanized tray for ten bottles of milk, which fits into a tin 
pot half-full of water, which is made to boil in the ordinary way. 
4. A graduated glass pitcher, for mixing the milk with water, etc., in 
certain proportions. 
5. A water bath, for warming each bottle of sterilized milk before using 
it, consisting simply of a tin cup with perforated double (inner) bottom. 
6. Bag-syringe, with nozzle for injecting soda solution through feeding- 
tubes, when such are used. 
Finally, bristle brushes, for cleansing bottles, tubes, etc. 
FIG. I 8c 3 
FIG. 2 
I FIGA 
FIG.5 
FIG .6 
Modus Operandi for Sterilizing Milk. 
Ten bottles are filled with milk to within half an inch of the neck. Into 
each bottle a perforated rubber stopper is pressed. The bottles are placed 
in tray No. 3, which is set in a pot of water. After the water has come to a 
boil, and expansion has taken place, the glass stoppers are pressed into the 
perforated rubber stopper, thus hermetically closing each bottle. The milk 
remains in the boiling water fifteen to twenty minutes longer, and is for that 
length of time under pressure in a temperature of 2120 F., which is sufficient 
to destroy all germs and impurities liable to produce fermentation. Milk so 
prepared will keep sweet four to six weeks, according to Soxhlet. 
When the milk is to be used, the bottle is put into hot water for a few 
minutes, until the contents are warm. The stopper is then removed, and an 
ordinary nipple attached. A long feeding-tube may also be used in the 
usual way, if desirable. Milk remaining in the bottle after the child has 
been fed is thrown away. 
Indications for the Use of Sterilized Milk. 
1. Sterilized milk should be administered to all children deprived of 
the breast. 
2. It may be given to children suffering from diarrhoea or convalescent from cholera infantum, when milk boiled in the ordinary way is not 
tolerated. 
3. A supply of sterilized milk is of the utmost importance for children 
while traveling. 
I have been told that in Munich about one thousand families have this 
apparatus in use ; it is also recommended by many physicians throughout 
Southern Germany. The price of Soxhlet’s utensils is $5 in Munich; with 
freight and duty, $8 in New York. 
Experiments. 
During the past four weeks I have made careful experiments in steriliz- 
ing and boiling milk, with a view of determining the proper manner of boil- 
and preserving milk for the use of infants, with the following results : 
1. Milk sterilized in Soxhlet’s apparatus, boiled 30 minutes, remained 
good 18 days. 
2. Milk boiled in small bottles for 15 minutes—before removing from 
the boiling water, the bottle was closed with a pledget of cotton. This milk 
remained good 5 days. 
3. Milk boiled in small bottles for 15 minutes; then taken from the 
water, and each bottle closed with a tight, non-perforated rubber stopper. 
This milk remained good 5 days. 
4. Milk boiled in small bottles for 15 minutes; then taken from the 
water, and each bottle immediately closed with a good quality cork stopper. 
This milk remained good 5 days. 
5. Milk boiled in a pot, and put into small bottles after cooling, and 
closed with cork stopper. Sour after 4 days. 
6. Milk boiled in a pot, and put into small bottles after cooling, and 
closed with non-perforated rubber stopper. Sour after 4 days. 
| This milk was kept in a spare room with temperature ranging 
from 50° to 70° F. Samples of milk from these experiments 
were shown to and examined by members of Pajdiatric Section 
of Academy.] 
7. Milk boiled in a pot in the usual manner and left standing in an open 
dish in a room with a temperature of 750 F. : (a) ordinary store-milk had 
a distinct sour taste and smell after 8 hours; (b) good “bottle-milk” 
“ turned ” after 15 hours. 
8. Milk boiled in a pot in the usual manner and placed in the ice-box in 
an open dish : (a) ordinary store-milk “ turned ” after 18 hours; good bottle- 
milk “turned ” after 26 hours. , 
Before proceeding I desire to call attention to the different results ob- 
tained by Soxhlet and myself regarding experiments Nos. 7 and 8, and would 
emphasize that Soxhlet has investigated the curdling point, his investiga- 
tion showing that milk curdles in 40 hours at 64° F., and in 19 hours at 88° F. 
At 950 F. milk curdles 330 per cent, more rapidly than at 58° F., fermenta- 
tion setting in very rapidly at a temperature of 950 F. I have paid no atten- 
tion to the curdling point, because curdled milk, as a rule, is not fed to 
healthy infants. It was my object to ascertain as near as possible the point 
at which a change takes place in ordinary good milk under ordinary circum- 
stances, which change should be perceptible to taste and smell, as a good 
and practical test of the condition of milk, and superior to the litmus-paper test. The latter test I have found to be unreliable, inasmuch as milk which 
is just sour enough to be unfit for use will not turn blue litmus paper red, 
such a color-change taking place only when milk is very sour and curdled. 
The milk used was of a very good quality, such as is sold in New York 
at io cents per bottle (quart), and is delivered in bottles closed with good 
quality cork stopper, except in two instances, as reported in Experiments 
Nos. 7 and 8, when store-milk was used. The sterilizing bottles were abso- 
lutely clean, and all stoppers used were put into boiling water before using. 
No difficulty was experienced in sterilizing milk No. i, except that in two 
bottles the pressure loosened the glass stoppers, on account of the softening 
of the rubber by the heat. This can be avoided by pressing the rubber 
stopper well into the neck of the bottle. 
In consequence of these experiments I have arrived at the following 
conclusions : 
1. The preparation and administration of sterilized milk can be managed 
in any well-regulated household. 
2. The boding of milk for 20 to 30 minutes under slight pressure, in 
small bottles hermetically closed, is all that is necessary to practically carry 
out the principle involved in sterilization—i. e., to destroy the germs of fer- 
mentation. 
3. The essential materials are : small bottles with Soxhlet’s stoppers 
and a tray. 
4. Milk boiled in small bottles for 20 minutes and immediately closed 
by rubber, cork or cotton stoppers, will keep sweet, if put on ice, for several 
days. 
5. The boiling of milk in the ordinary way is faulty. All milk for 
infants’and children’s use should be boiled in small bottles* in a water bath 
for 20 minutes, when it will keep much longer than if boiled in the ordinary 
way and the usual length of time. 
6. The transportation of milk should take place in refrigerator-cars 
during the summer months. This should be secured by legal enactment. 
7. An apparatus for properly boiling and preserving milk for infants’ 
use should be at once introduced into every well-regulated household. The 
essential utensils are : small bottles (5 to 6 oz.) with combination stoppers 
(Soxhlet’s) and a tray of tin or galvanized iron—all procurable for a very 
moderate sum. A good brush for cleaning the bottles should accompany 
each set; also a tin dipper, with perforated inner bottom, for warming the 
milk before giving it. Ten spare bottles, with a few ordinary nipples, would 
make the outfit complete. To facilitate handling and transportation, such 
an outfit could be packed in a wooden box one foot square and high, and 
provided with a common handle. All the other utensils, as advised by 
Soxhlet, are superfluous, the more so, as complicated apparatus is difficult to 
introduce for family use and soon discarded. Feeding-tubes are difficult to 
keep clean, and should not be used. The ordinary nipples for sale every- 
where will fit the bottles, and such nipples can be turned inside out and 
thoroughly cleansed. It would be a good plan to stamp into the tin cover 
of the boiling pot: Boil for twenty minutes, this being important in view of 
the fact that the printed directions are liable to be lost or mislaid. 
* About thirteen years ago Dr. A. Jacobi recommended that milk should be boiled and put into 
small bottles, tightly corked, and kept on ice upside down. See also A. Jacobi, “ Intestinal Dis- 
eases of Infancy and Childhood,” 1888.