1815.] Elements of Organic Nature are cemhined. ?r.7 



We can hardly doubt, therefore, that crystallized sugar of milk 

 is composed of O + C + 2 H. But it would be a mistake to 

 suppose that pure sugar of milk has such a composition. It con- 

 tains combined water as well as common sugar. If it be fused at a 

 temperature not sufliciently high to decompose it, a great deal of 

 water is disengaged, which is not formed by any alteration in the 

 sugar, as it remains colourless and gives a colourless solution. To 

 succeed in this experiment it must be made on a very small scale. 

 Common sugar does not give out any water till it begins to become 

 brown. 



To determine the quantity of water in sugar of milk, I made an 

 experiment similar to that made with common sugar. I took three 

 parts of sugar of milk and mixed them with 20 parts of oxide of 

 lead, and digested the mixture with a little water, till the whole 

 su-^ar was absorbed by tlie oxide of lead, and the mass was reduced 

 to the consistence of a thick paste. This mass, dried in a vacuum 

 at the ordinary temperature of the atmosphere, lost 0-34 of its 

 wei"ht. When heated to 212*^ in a vacuum, it sustained an addi- 

 tion'al loss of 0-04, making in all 0-38, equivalent to 12_333 per 

 cent. These 12} contain 108 of oxygen, which is the fifth part 

 of all the oxygen contained in the crystallized sugar of milk. The 

 small deviation is too inconsiderable to be owing to any thing else 

 than an error in th.e experiment. Hence it follows, that sugar of 

 milk is combined with a quantity of water, which contains one 

 fourth as much oxygen as itself. Experiment in that case ought to 

 have given 12-04 of water, instead of 12-333. 



To determine the capacity of saturation of sugar of milk I di- 

 gested a mixture of it and oxide of lead in water, in a corked 

 phial ; the oxide had been obtained by burning oxalate of lead in 

 an open vessel, because the oxide thus prepared is in the state of a 

 very fine powder. On attempting to assist the solution of the oxide 

 by heat, 1 found that the temperature must not be raised higher 

 than MO'', because at a higher tenipcrature the sugar of milk is 

 decomposed by the action of the oxide of lead ; the liquid becomes 

 brown, and assumes an empyreumatie odour, though it has not 

 hccn raised to the boiling temperature. Bouillon Lagrange, and 

 Vogel, have already observed this jjroperty of sugar of milk to be 

 decomposed by the more powerful bases. 



A strong solution of sugar of millv, digested during eight liours 

 with oxide of lead, gave a colourless milky solution, of a taste a 

 little sweet, alkaline, and astringent. 'J'his solution contained a 

 smiill quantity of a wbitc, ligiii, and mucous matter, whicli was 

 caMly separated from the oxide of lead undissolved, by agitating the 

 vessel. I poured the solution, holding the mucous matter sus- 

 pended upon a filter; and as tlie liquid pa.ssid very slowly, I placed 

 it under a glass jar, into which I had introduced a quantity of moist 

 hydrate of lime, in order to absorl> the carbonic acid gas of the air, 

 and prevent the liquid from being allccted by it. 



