1908.]-. = |. Hem-agglutinins, etc., in the Blood. 533 
incubated usually for 1 hour at 37° C. in a horizontal position in an incubator 
suitable for such purposes. At the expiration of this time, the contents of 
the capillary tube were blown out on to a slide, a glass cover-slip was placed 
over the mixture and the specimen was examined microscopically. In many 
instances, the agelutinative effect was obvious to the naked eye. 
_ In some cases, incubation of the tubes was allowed to continue for several 
hours, but no advantage was gained by the extra time, and, in some instances, 
a hemolytic action interfered with the results. 
Experiments were also made with the centrifuged red cells undiluted with 
salt solution for the agglutination tests, but the results were unsatisfactory. 
A definite suspension of washed red cells in salt solution, and a definite 
volume of the corpuscles and of serum were employed, so as to obtain certain 
essential advantages :-— 
(1) By employing the washed red cells, any agglutination which occurs 
must be due to the interaction of the red cells and of the serum added. 
(2) We can add any desired serum and examine its properties, which could 
not be done with the unwashed red cells. 
It was found that even in cases in which the agglutinative effect brought 
about by mixing equal volumes of serum and red cells was marked, yet if we 
diluted the serum with normal saline previous to the mixing with the red 
cells, the effect was considerably diminished, and, according to the amount of 
dilution, rapidly lost. This confirms the observations made some years ago 
by Shattock. If, however, we diluted the specific serum with an inactive 
serum, the results were much more satisfactory than by the method of dilution 
previously referred to. 
Hem-agglutination. 
Shattock,* in 1899, communicated a paper to the Pathological Society of 
London, on chromocyte clumping in acute pneumonia and certain other 
diseases, His observations were carried out for the purpose of determining 
whether the blood serum from patients suffering from acute pneumonia, 
erysipelas, or acute rheumatism, had any effect upon the rouleaux formation 
of normal human blood. He found, by adding 1 loop of normal human blood 
to 1 loop of pneumonic serum, that the chromocytes ran together. On the 
nodal points the discs were clustered into large knotted masses. Similar 
observations were made in the blood from the other acute diseases just 
referred to. It is interesting, however, to note that in all these observations 
mentioned by Shattock in his communication, which was the first on this 
* §. G. Shattock, “Chromocyte Clumping in Acute Pneumonia and certain other 
Diseases, and the Significance of the Buffy Coat in Shed Blood,” ‘ he Journal of Pathology 
and Bacteriology, 1900, vol. 6, No. 3, p. 303. 
