ADAPTATION OF FISH TO TEMPERATURE 545 
cooler climate of Nieder Oesterreich darkens already at a tempera- 
ture of 25° and becomes perfectly black at a slightly higher tem- 
perature. Lacerta muralis from the warmer climate of Italy 
remains perfectly normal at 25° and darkens only at 37°. Kam- 
merer points out that the higher temperature at which the latter 
lizards had lived prevented the effects which the same rise in tem- 
perature produced in lizards that had previously lived at a lower 
temperature. ; 
Il. THE INFLUENCE OF THE CONCENTRATION OF THE 
SOLUTION UPON THE RESISTANCE OF FUN- 
DULUS TO HIGH TEMPERATURE 
We used as material for our experiment half-grown Fundulus 
which were caught in Long Island Sound in January and kept in a 
room in the laboratory, the temperature of which varied a little 
around 10°C. Two fish were put into each of the following solu- 
tions: H.O, m/128, m/64, m/32, m/16, m/8, m/4, NaCl + KCI+ 
CaCl, in the usual proportion. It was found that the higher 
the concentration of the solution—up to a certain lmit—the 
longer the fish could survive in a given high temperature. The 
method consisted in putting a number of battery jars with 500 cc. 
of the solution into a large water bath the temperature of which 
was constantly watched and kept constant. When all the solu- 
tions had reached the desired temperature the fish were introduced. 
In a number of cases the experiment was continued for several 
days in a bacteriological thermostat. Table 1 gives the duration 
of life for these fish in each of the solutions for various tempera- 
TABLE 1 
a me gee L 7) ee 
DURATION OF LIFE OF FUNDULUS IN | 
TEMPERA-| Rtas | ut Za Lf ay eer ui 
TURE | | | C par 
H20 m/128 | m/64 | m/32 m/16 m/S | m/4 | 3m aN 
Pace nreniiadets | wader: lander. \imdere tindees ander olnrle ten 
27° lhr. | 2hrs.| 2 hrs.| indef. | indef. | indef. | indef. | indef. 
29° Ro Neale 50’, 62’ ‘| 90’ | indef. | indef. | indef. 
oe | 13" 25’ Li’ 50’ | indef. indef. | indef. | 
33° 2’ ad SOL a 4 be Sey ASOn 
