WHAT IS WINE? 
155 
might lead us to suppose, being more masked by the spirit, &c. 
The proportion of volatile acid is about the same as in claret, 
and they contain little or no tartaric acid. The amount of 
sugar is also very variable, ranging from 0 to 4% and more. 
Of all the fortified wines examined, sherries are the only ones, 
Madeira excepted, which, as a class, contain more volatile than 
fixed ethers. All true sherries leave a high proportion of ash, 
owing to the universal practice of adding plaster of Paris to the 
must. This ash consists chiefly of sulphate of potassium,* and 
contains frequently neither carbonates or chlorides, though the 
latter are never absent from the wine itself. Phosphates are 
also present in small proportions only, most likely also owing 
to the practice of plastering, by which some of the phosphoric 
acid of the must is precipitated. 
Sherry, as indeed all fortified wines, can scarcely be regarded 
as a beverage, except perhaps when diluted with water. As a 
stimulant it is, however, of considerable virtue, and though it is 
frequently asserted that its action is due to the high percentage 
of alcohol, it is in many cases far preferable to brandy. As 
wines to be sipped, not drunk, the better sherries form an 
extremely fine class, possessing strength, sufficient body, fine 
flavour, and very exquisite bouquet, but to attain this perfection 
they must be kept for many years in bottle. 
Madeira . — This wine, as its name implies, comes from the 
island of Madeira, which, though not large, produced formerly 
upwards of 2,000,000 gallons yearly. Owing to the prevalence, 
during several years, of the oidium, or grape disease, which de- 
stroyed the vines, the yield was reduced to next to nothing, and 
many vineyards were uprooted and used for the cultivation of 
sugar-cane. At present, however, the vines have either been 
replaced or are in course of replacement in most of the old 
vineyards, and the production of the island has again risen 
to above 500,000 gallons annually. 
Madeira, like all southern wines, is fortified, its strength vary- 
ing usually between 17 and 20%. In its general characters it 
greatly resembles sherry: like this, it has a greater proportion of 
volatile than fixed ethers, contains about the same amount of 
acids and sugar, and is also almost free from tartaric acid. It 
leaves rather a high proportion of ash in which sulphates pre~ 
* Many sherries contain as much as sixty grains of sulphate of potassium 
per bottle; in other words, a strong purgative dose even for an adult. 
Potassium salts, when given in large doses, have moreover a depressing 
effect on the heart’s action, and it is well worthy of careful observation 
whether the good effect intended to be produced by the administration of 
the sherry, is not sometimes completely counteracted by the large dose of 
sulphate of potassium given simultaneously. In such cases Madeira might 
perhaps be substituted for the sherry with advantage, 
