50 BACTERIOLOGY 



and has been frequently used in the author's Institute. 

 We employ for this purpose the white of plovers' eggs, as 

 these are easily bought in the spring time. When a plover's 

 egg is opened after washing with corrosive sublimate solu- 

 tion, there is found round the vitelline membrane a con- 

 densed mass of albumen, outside of which the white is 

 clearer and less dense. If this outer white is distributed 

 into narrow test-tubes, and these laid slanting and subjected 

 to a temperature sufficient to coagulate the albumen, a clear 

 gelatinous transparent mass is obtained, which can be used 

 for the most widely-differing cultures : for example, even 

 gonococci will grow upon it, as Von Schrotter and F. Winkler 

 have shown in the author's Institute, and pigment-form- 

 ing micro-organisms develop particularly well upon this 

 medium. 



Admixtures of various other substances grape-sugar, 

 dextrine, paste, and in fact all bodies soluble in water, and 

 which have not an acid reaction can be made with it, so 

 as to modify it in various ways. The medium can also be 

 prepared by diluting the concentrated albuminous mass 

 with water but in that case the white of egg must first be 

 filtered. 



Although investigations show that no micro-organisms 

 can be detected in the normal unfecundated plover's egg, it 

 is nevertheless advisable to subject the test-tubes when 

 filled to a fractional sterilisation before use. 



Plover's egg albumen is also applicable to plate cultures, 

 but after careful sterilisation it must be dried on a sterile 

 glass plate over sulphuric acid in the receiver (also steri- 

 lised) of an air-pump, and then kept in the moist chamber 

 after inoculation. The preparation of plates may, however, 

 be facilitated by mixing the albumen with gelatine or agar. 



Hens' eggs. According to Hiippe and Heim, hen's eggs 

 may themselves be used with advantage as nutrient media. 



