São Roque (waters)

In the article Machico (Health Resort), we have already referred to the waters of the springs of São Roque (‘St Roch’) in the town (vila) of Machico, which have remarkable therapeutic virtues, as is generally known and as many distinguished physicians affirm. Since the results of the analysis of these waters carried out by the illustrious chemist and analyst Charles Lapierre are hard to find today, we believe it of some interest to reproduce them here.

These tests showed that the water contained: many chlorides, a fair amount of sulphates, a fair amount of carbonates, a fair amount of lime and magnesia, and much sodium. B. – Quantitative tests (per litre). 1. Direct results of the analysis: residue at 180° 0.5324 grams; dissolved oxygen 6.3 cc; combined carbonic acid (from the carbonates) 0.0320 g; silica, iron oxide, alumina 0.0220; lime (CaO) 0.0288 g; magnesia (Mg.) 0.0397; sodium 0,1.460; sulphuric acid (SO3) 0.0222; total chlorine 0,2.485. Potassium nitrate 0.0030, or nitric nitrogen 0.42 mg.

Organic matter, acid and alkaline solution – nil; ammonia nil; nitrites nil. 2. Grouping of the elements (per litre): silica, iron oxide, alumina 0.0025; potassium nitrate 0.0030; magnesium sulphate 0.0423; calcium carbonate 0.0407; magnesium carbonate 0.0269; magnesium chloride 0.0305; sodium chloride 0.3717; sum of the elements 0.5377. Residue 0.5324.

Comparing the sum of the elements determined with the residue obtained directly by evaporation confirms the accuracy of the analysis.

1st Number of germs – I have not described the methods followed, having already done so in the report on the waters of Funchal that I addressed to the Municipal Council of that city, which was printed in Coimbra Medica and in Madeiran newspapers.

Nevertheless, I repeat that no great importance should be attached to the absolute value of the figures obtained, since the number of germs increases greatly whenever the water is subjected to changes in its medium, temperature, etc. Using the gelatine-plate method, with the plates examined 8 and 13 [days] after sowing, I found per cubic centimetre: 2,700 bacteria at 8 days and 3,060 at 13 days; fungi, 150 at 8 days and 160 at 13 days. According to Miguel’s classifications, it falls into the group of ‘Tolerable Water’.

The species that developed were all common saprophytes, none of them being regarded today as pathogenic.

• 2. Search for coliform species – The water, subjected simultaneously to the Elsner and Péré methods (see the Funchal report), showed no coliform species in the numerous plates sown.

Greater importance should be attached to this result than to the preceding one, based on the number of germs.

In the first few days two colonies appeared that were suspect because of their microscopic appearance; they fermented sugars but did not produce indole. After six days they liquefied the gelatine, so they were not bacteria of the coli bacillus group.

The absence of these species agrees with the chemical analysis and demonstrates that the water of the ‘São Roque’ spring is well captured and piped, with no communication between the spring and the nearby ground that could give rise to contamination affecting the purity of its water.

III CONCLUSION – The mineral-medicinal water of the ‘São Roque’ spring belongs to the class of hypothermal, hyposaline, sodium-chloride waters.

In its chemical composition it resembles, on the mainland, the waters of Amieira, analysed by Mr Santos e Silva, and the waters of Bicanho and of ‘Geiras’ (near ‘Amieira’) and of Fonte Nova (near Torres Vedras), which are also mineral-medicinal and which I have analysed.

Both my analyses and those of ‘Amieira’ were published in the Coimbra Medica.

By analogy with these waters, whose therapeutic effects are already known, it is natural that the water of the ‘São Roque’ spring should be suitable for the pathological cases in which the former give positive results, for example scrofula, skin complaints, gastric disorders, etc.

However, it is not for me to go into this matter further, since that is not the role of the chemist but of the physician, who, in the light of the water’s composition and the results obtained, could form a scientifically based opinion.

I may add that the bacteriological analysis indicates that the water appears to be in good condition at its source. Coimbra, 4 July 1896.

Charles Lepierre

Professor of chemistry at the Industrial School of Coimbra (Escola Industrial de Coimbra) and demonstrator at the Microbiology Laboratory (Gabinete de Microbiologia) of the University, corresponding member of the Royal Academy of Sciences of Lisbon (Academia Real das Sciencias de Lisboa), Officer of the Order of São Tiago, etc.’