Stability of Antisera and Sera 123 



The Stability of H aematosera and Sera sealed in vitro. 



In my paper of 21, xi. 1901, I stated that some of my antisera 

 had given good reactions after being sealed in a pure state for seven 

 months in vitro. Wassermann and Schiitze (18, II. 1901) had only kept 

 antisera on ice up to two weeks. They state that fresh antisera give 

 greater reactions. I have some antisera which are effective after 

 14 months of storage. I have preferred to keep them on ice, being under 

 the impression that they remain potent longer at low temperatures. In 

 the majority of cases antisera deteriorate markedly after 3 4 months. 

 My observations in this respect have been confirmed by Uhlenhuth 

 (25, iv. 1901), Rostoski (1902, b, p. 17) 1 , and Linossier and Lemoine 

 (21, in. 1902) who have kept antisera for three months. Uhlenhuth how- 

 ever added 0'5 /o carbolic acid to them, which I consider disadvantageous, 

 for the reason that carbolized antisera tend to cloud blood solutions to 

 which they are added, irrespective of their being homologous. Strube 

 (12, vi. 1902) preserved antisera, both pure and with 0'2/ carbolic acid 

 for three months. Moro (31, x. 1901) found sealed antisera to give 

 reactions after several months, a fact also observed by Biondi (1902, 

 p. 17). Robin (20, xn. 1902) found antiserum preserved four weeks 

 to give a reaction in two hours whereas it gave a reaction in 30 minutes 

 at first 2 . 



The precipitable substance appears to be even more stable. In my 

 paper of v. 1901 1 stated that I had successfully immunified rabbits with 

 old antidiphtherial horse serum preserved two years and seven months in 

 the laboratory at room temperature. This serum was exposed through- 

 out that time to diffuse light and room temperature, preservation being 

 secured through trikresol. The serum has given reactions with anti- 

 horse serum after more than four years. Similarly I immunified rabbits 

 with human pleuritic exudate preserved for six months with chloroform 

 at room temperature, and this has also given reactions after being 

 preserved for over two years. Further observations with regard to 

 the durability of sealed fluid sera in this respect have since been made 

 in this laboratory by Graham-Smith and Sanger (1903, p. 273) who 

 report as follows : 



" A few quantitative experiments quoted below made on fluid sera, 

 preserved by sealing in glass bulbs, indicate that such sera lose their 



1 Preserved with chloroform. 



2 Bobin's antiserum was evidently weak at the start. 



