539 
AUTO AGGLUTINATION IN THE BLOOD OF NORMAL 
ANIMALS 
Attention has already been drawn to the fact that a certain 
amount of auto-agglutination was frequently observed in the 
control tests of normal blood. Some years ago Klein found 
auto-agglutinin to be present in the serum of a number of normal 
horses. 
Landsteinert demonstrated the existence of a similar substance 
in the blood of rabbits, horses, dogs, and cattle. 
Other writers, on the contrary, deny the existence of 
auto-agglutinin in normal blood. Dudgeon^ in a recent papei 
states that auto-agglutination does not occur in normal human 
blood. 
It was decided to re-investigate this subject more fully, using 
the blood of a considerable number of normal animals of different 
kinds. 
Technique . — The blood was obtained from a convenient vein, 
and the defibrinated plasma separated from the red corpuscles at 
37 ° C. in the manner already described. The red corpuscles were 
washed three times in warm saline solution, and finally a 5 P ei 
cent, suspension made in 0'9 per cent, sodium chloride solution. 
Equal volumes of the defibrinated plasma and red cell suspension 
were drawn up together into three fine pipettes which were then 
subjected to a temperature of o , 15°, and 37' C. respectively. The 
pipettes were kept in the vertical position, and the contents 
examined for auto-agglutination with the aid ol a lens from time 
to time. It was found in the majority of cases that the test could 
not well be continued for longer than one hour, owing to the fact 
that in most cases the erythrocytes had subsided to a marked degree 
after the lapse of this period. At times the citrated plasma was 
substituted for the defibrinated plasma. The same precautions 
regarding temperature were taken, and only vei> small amounts o 
citrate solution (not more than a tenth of the volume of plasma) 
* ‘ Bcitragc zur Kcnnlniss Her Agglutination rother Blutkorpcrchen, W ten. Klin, 
f Uebcr Bcziehungcn zwUchen deni Blutecrum und den Krtrperzellen,’ Munch. Med. Woch., 
1003, No. 42. 
I ' On the Presence of Haemagglutinins, etc., in the 
Infectious Diseases in Man,' Roy. Soc. Proc., 1909, B, 
Blood obtained from Infectious and Non- 
Vol. LXXXI. p. 207. 
