K. LANDSTEINER 905 



groups. One may assume, however, that the injected agglutinins are not entirely in- 

 different, and it would seem plausible to prefer donors with the same group as the 

 recipient. Actually, some clinical experiences support this view (e.g., Unger/ Jones 

 and Glynn,^ Kubanyi,^ Butka,^ Kraft)^, and a number of surgeons avoid the use 

 of universal donors, using whenever possible only blood of the recipient's group. A 

 systematic investigation of this aspect is still wanting. The use of universal donors 

 with sera of exceptionally high agglutinin titre is directly contraindicated, as was 

 pointed out by Levine and Mabee'' and others.'^ 



Two methods are generally employed for the selection of donors, the grouping of 

 the blood of recipient and donor and the direct cross-test. Since isohemolysis does not 

 seem to occur without agglutination it is sufficient to make agglutination tests only; 

 occasionally in such tests hemolysis also may appear. This has the same practical 

 significance as agglutination. 



Direct matching is advisable in view of the possible occurrence of exceptional 

 atypical agglutinins and donors with unusually high agglutinin titre. It also serves as 

 a check for the grouping. It is not quite safe to depend on the direct matching alone 

 and to omit the grouping, because in cases of weak agglutinins incompatibility 

 may escape attention in the former test. Moreover, the selection of donors is easier 

 when the group of the patient is determined and donors of known groups are available. 



For the agglutination test several methods have been proposed.^ 



The grouping can easily be made by mixing a drop of serum A and serum B, respectively, 

 with a drop of 2-5 per cent blood suspension on a slide, tipping it repeatedly to hasten clump- 

 ing. After some minutes the preparation may be covered with a cover slip. Ordinarily the 

 test should be under observation for at least fifteen minutes. The present writer prefers — 

 especially when numerous bloods are examined — to set up the tests in small tubes (7-mm. 

 diameter) using one drop each of serum, saline and blood-cell suspension (equivalent to 2.5 

 per cent normal blood). This dilution of the serum is generally sufficient to prevent pseudo- 

 agglutination. The emulsion can be prepared simply by mixing a few drops of blood with the 

 necessary amount of saline solution; citrated blood may also be used, preferably after wash- 

 ing. The tubes are shaken several times and a drop of the mixture is taken up by means of a 

 thin glass rod and examined microscopically with low magnification. The reaction occurs 

 generally within a few minutes. In order to detect unusually feeble reactions the negative 

 tests are re-examined after one hour. Control tests with known cells A and B should be 

 included. Special care must be taken to select test sera of known high agglutinating power. 

 Sterile test sera can be kept preferably in the icebox or may be stored with a preservative 

 (e.g., chloroform). 



' Unger, L. J.: loc. cil. 



2 Jones, A. R., and Glynn, E. E., loc. cit. 



3 Kubanyi, A.: Zentralbl.f. Chir., 51, 1503. 1924. 

 '•Butka, H. E.: California b' West. Med., 24, 74. 1926. 

 5 Kraft, R.: Arch.f. klin. Chir., 134, 834. 1925. 

 'Levine, P., and Mabee, J.: /. Immunol., 8, 425. 1923. 



' Cf. Freeman, G. C, and Whitehouse, H. J.: Am. J. M. Sc, 172, 664. 1926. 



* A detailed consideration of the technique is given in Schiff, F. : Die Technik der Blutgrtippett- 

 Milersiichimg. Berlin: Springer, 1926; Lattes, L.: Abderhaldens Handbuch der bioch. Arbeitsmeth., Aht. 

 XIII, TeU 2, Heft 5, S. 719. 1927. 



