BLOOD OF FRESH-WATER MUSSELS 
533 
Table 15. — Changes in specific gravity and pH of the blood of fresh-water mussels in solutions of 
magnesium salts 
MAGNESIUM SULPHATE, 1.00 PER CENT 
Scientific name 
Common name 
Flours of 
exposure 
Condition of animal 
pH 
Specific 
gravity 
4 
Heart beating. 
7.7 
1. 0022 
Do 
do 
4 
do 
8. 1 
1.0024 
Do 
__do .. 
4 
do 
8. 1 
1. 0026 
Niggerhead 
20 
do ... 
7.2 
1.0035 
Do 
do ... 
20 
_ __do ... _ 
7.7 
1. 0035 
Do 
do 
20 
do __ 
7.7 
1. 0041 
Washboard _ 
20 
Moribund 
8. 1 
1. 0044 
~Do__. 
do _ __ 
20 
Heart beating. 
7.9 
1. 0047 
do ... 
20 
do _ 
7. 5 
1. 0040 
Do A 
do 
20 
do . 
7.5 
1.0043 
MAGNESIUM SULPHATE, 0.50 PER CENT 
Washboard 
4 
Heart beating. .... 
8.0 
1.0026 
TDo 
do 
4 
Moribund 
8. 1 
1.0028 
Do... 
do 
4 
Heart beating. ... ... ... 
7.7 
1.0035 
Do 
do 
24 
Moribund 
7.7 
1. 0028 
Do... 
do 
24 
Heart beating 
8. 1 
1. 0029 
Do 
24 
Moribund 
8.0 
1. 0032 
Do 
do 
28 
Heart beating.. 
7.7 
1.0027 
Do 
do .. 
28 
do 
7.7 
1.0029 
28 
Moribund __ 
7.7 
1. 0032 
MAGNESIUM SULPHATE, 0.25 PER CENT 
Butterfly ... . ... 
24 
Heart beating . . . 
8. 1 
1.0028 
24 
do ... 
8. 1 
1. 0027 
Pig toe.. _ 
24 
. ...do 
8.0 
1.0015 
Washboard 
48 
8. 1 
1. 0018 
do ._ . ... 
48 
do . . 
8. 1 
1. 0020 
Do... 
do 
48 
Moribund 
8. 1 
1 . 0020 
Do 
do 
96 
Heart beating ... 
8. 1 
1. 0017 
Butterfly . 
9R 
. ...do 
8. 1 
1. 0019 
124 
8 5 
1 0024 
Pope’s purpie 
124 
do. 
7.9 
1. 0028 
MAGNESIUM CHLORIDE, 0.50 PER CENT 
Fat mucket. 
8 
Heart beating. _ . ... __ . 
7.9 
1.0029 
Do A 
do .. 
8 
do 
7.8 
1. 0030 
Do... 
do 
8 
do 
7.9 
1. 0031 
Do... 
do 
8 
do.. 
8.0 
1. 0032 
Do... 
__ .do ... ... . 
20 
do 
8.0 
1. 0030 
Do... 
20 
.. .do 
7.8 
1. 0032 
River mucket 
20 
Dead 
8. 1 
1. 0031 
Do 
..do 
72 
Heart beating 
8. 1 
1. 0021 
Do... 
do 
72 
do ... 
7.7 
1. 0025 
Note.— "M oribund,” under condition of animal, designates a mussel in which the heart was not beating when shell was 
opened, but an animal still responding to tactile stimulation of the foot or mantle. 
CALCIUM SALTS 
As calcium salts play such an important part in the life activities of the fresh- 
water mussels, even to limiting the distribution of these animals very largely to regions 
where calcium salts are readily available in the water, calcium salts have been made 
the basis of a more detailed series of studies, which are only summarized in part here. 
In Table 16 and Figure 13 individual data for a series of calcium tests are presented. 
These will suffice to show the main points in relation to the blood. 
The responses of the mussels living in calcium-salt solutions were very quickly 
adjusted, so that if the solutions were not too strong the mussels behaved much as 
in ordinary fresh water. The specific gravity of the blood of animals transferred to 
the stronger solutions rose during the first 24 to 48 hours, after which the readings 
range about the normal blood specific gravity. Four high cases (see fig. 13), one at 
