I50 DONALDSON. [VoL TX: 
Additional Observations. — Before leaving the sheep, we have 
yet to mention some of the most common methods of harden- 
ing in which modifications of the simple bichromate solutions 
are employed, or where two different fluids are used in suc- 
cession. 
On making an average of the changes in four series of 
hemiencephala ina 2}% solution of bichromate of potash we 
have the following figures shown in the next table. 
This may be taken as a standard. 
TABLE 20. 
Average increase of 4 hemiencephala in 2}% solution of bichromate of potash. 
Time.—Days. PERCENTAGE INCREASE. 
1.05 18.8 
2.20 24.8 
3.12 31.3 
5.12 33-0 
12.12 36.0 
The maximum increase in any of these four specimens 
during the next 660 days is less than 2%, so that the table 
presents fairly well the resulting increase in weight. 
If we compare with this a solution containing the same 
percentage of bichromate of potash to which 15% of sodium 
sulphate has been added, the increase in weight is found to be 
smaller, Vzde the following table :— 
“ABER soi 
Average increase of 4 hemiencephala in 24% solution of bichromate of potash 
plus }% sulphate of soda. 
Time.—Days. PERCENTAGE INCREASE. 
9 14.2 
1.0 16.5 
2.9 24.5 
3.0 28.6 
Got 30.5 
7.0 31.9 
12.0 32.0 
41.0 33-2 
