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5.—Some points on the variations of the erythrocytes of individuals of the
same species to lysis by hypotonic solutions and by specific serum.
(1) Having first ascertained the tonicity of the blood of a rabbit, expressed in
terms of NaCl, a comparison was made between erythrocytes suspended in their
plasma and washed erythrocytes suspended in 0·85 per cent. NaCl to determine whether
the lysis by hypotonic salt solution began and ended at the same points in each ease.
No difference in the points could be observed, so it may be concluded that erythrocytes
are lysed by hypotonic solutions of exactly equivalent strengths whether the dilution
be made of the whole blood, due allowance being made for the normal tonicity of the
plasma, or whether washed erythrocytes freed from plasma be used.
(2) The serum of goat B , which lysed sheep erythrocytes specifically, was tested
with the washed erythrocytes from six different sheep. Practically no difference was
observed in the degree of lysis in the six series, so it may be concluded that the
erythrocytes obtained from healthy individuals of any species do not differ appreciably
in the degree of their susceptibility to lysis by a specific lytic serum.
(3) Erythrocytes obtained from the same six sheep were lysed in different
degrees by hypotonic solutions, which shows that there is no apparent relation between
the resistance of the erythrocytes to lysis by hypotonic solutions and their suscepti
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bility to lysis by a specific serum.
(4) Erythrocytes obtained from six different rabbits were lysed in each case
to precisely the same degree by the serum of one normal goat showing that, as in the
case of the specific hæmolysin ; a normal hæmolysin has an equal action on the
erythrocytes of different individuals.
(5) The serums of different individuals, however, contain different amounts of
hæmolysin for erythrocytes from one individual of another species. For example,
using the serums of twelve different normal rabbits and the erythrocytes from one
normal goat varying degrees of lysis occurred in the twelve series.
6.—To ascertain within what limits the solvent power of an animal's serum
on the erythrocytes of some other species may be expected to vary
from time to time.
Having already found that erythrocytes taken from different healthy animals are
lysed in the same degree by a serum from another species we have only one composite
variable to measure in determining the relative quantity of lysin present from day to
day in a serum.
The serum of a normal goat was tested every second day from January 18th to 28th
and then weekly from February 4th, April 5th, 1909, against washed rabbit erythrocytes.
Between January 18th to 28th, a concentration of 17 per cent. to 22 per cent. of
serum in a total volume of 2 cc. fluid was required to completely dissolve 0·05 cc. of
rabbit erythrocytes, i.e., from 7 to 9 parts of serum to 1 part of erythrocytes.
Between February 4th and April 5th from 12 per cent. to 22 per cent. of serum
was required, i.e., from 5 to 9 parts of serum to 1 part of erythrocytes.
During the observation period of 2 ½ months, the serum of this goat varied so
much in its contained lysin that, on some occasions, only 5 parts of serum were required
to dissolve 1 part of erythrocytes and on other occasions 9 parts of serum, or nearly
double the quantity.
Chart 2 shows the rabbit-erythrocyte-lysin content of the serum of a goat between
January 18th and April 5th, 1909.