34 PRELIMINARY COLD STORAGE STUDIES. 



BACTERIOLOGICAL EXAMINATIONS 

 TECHNIQUE. 



Ten fresh eggs and eight cold-storage eggs were examined for the 

 number and the species of organisms present. The technique of 

 this examination was as follows: The eggs were washed in a solution 

 of bichlorid of mercury 1 to 1,000, or 5 per cent carbolic acid, for a 

 few minutes, after which they were dried with sterile absorbent 

 cotton and placed with the large end uppermost in a .small beaker. 

 The air space was then scorched with a gas flame for a few seconds. 

 An opening was made immediately into the cavity with sterile for- 

 ceps, a sufficient amount of shell being removed without rupturing 

 the membrane below. When this was accomplished the latter was 

 broken with a hot platinum spatula and with a sterile pipette 0.5 cc 

 of the white of the egg was quickly removed and placed in the neces- 

 sary petri plates for cultures. The remaining egg white was then 

 decanted, leaving the unbroken yolk in the shell. With another 

 sterile pipette the yolk sack was ruptured and suitable portions of 

 its contents were removed for study. While such a procedure guards 

 against contamination, the breaking up of the respective layers of 

 the egg when out of the shell is difficult, and sometimes the inability 

 to do so interferes seriously with the obtaining of quantitative 

 results. With the eggs which have been in cold storage for consid- 

 erable periods a separation of the whites and yolks is not possible. 



The first examination of cold-storage eggs, which was made at the 

 expiration of the three months' period, showed white and yolk still 

 separate and the limiting membranes in a fair condition. At the end 

 of six or eight months, however, there was an entire change in the 

 character of the egg, the yolk and white having blended, so that it- 

 was necessary to examine the total egg rather than its constituent 

 layers. 



DISCUSSION OF RESULTS. 



The accompanying tables indicate the results of these examina- 

 tions. It will be observed that the fresh eggs had originally but 

 few organisms, though in two cases, notably in the yolk, they were 

 fairly numerous. The fact is also noteworthy that the most abun- 

 dant growth occurred with the fresh eggs at body heat, and later 

 at 15-20 C. As far as the kinds of organisms are concerned, fungi, 

 yeasts, and bacteria of various types were present. As one would 

 expect, they were mostly air-borne organisms and of the types existing 

 in the soil, cereals, water, etc. 



At the expiration of three months in cold storage, as will be seen 

 in the following table, a very great increase in the number of organ- 



Made by G. W. Stiles, jr., in charge of bacteriological chemistry, Washington, D. C. 



