136 Mr J. Girardin's Remarks on Sir ff. Davy's 



quantity. Besides, the curd or caseum of pure milk can be 

 easily distinguished from that with the emulsion, by its consis- 

 tency, and by the grease which the latter yields when exposed 

 for some time to white paper. 



' , To prevent the milk from turning sour and curdUng, as it is 

 -so apt to do in the heat of summer, the milkmen add a small 

 quantity of sub-carbonate of potash, or soda, which, saturating 

 the acetic acid as it forms, prevents coagulation or separation of 

 ■the curd ; and some of them practise this with so much success, 

 as to o-ain the reputation of selling milk that never turns. Often 

 when coagulation has taken place, they restore the fluidity by a 

 greater or less addition of one or other of the fixed alkalies. The 

 acetate which is thus formed has no injurious effects ; and, be- 

 sides, milk contains naturally a small quantity of acetate of 

 potash, but not an atom of free or carbonated alkali. 



It is proposed froxn the result of these investigations, that the 

 authorities should ordain, 1st, That no milk should be sold except 

 in sealed measures ; and, 9dly, That, in each quarter of the 

 city, one or two pharmaceutists should be charged with the duty 

 of examining from time to time the quality of the milk offered for 

 sale, and that penalties should be exacted for every fraudulent 

 alteration ,of quantity or quality. — Annates d'Hygiene Puhlique 

 et de Medecine Legale, July 1829. 



Remarks on S'ir Humphrey Davy's Opinions respecting Vol- 

 canic Phenomena. By Mr W. J. Girardin. 



After presenting a succinct account of Sir H. Davy's ideas on 

 the subject of volcanoes, M. Girardin makes the following re- 

 marks. 



In the first place, is it indeed demonstrated that the sea com- 

 municates with the volcanic foci ? Geologists of all ages have 

 attributed a great degree of importance to the circumstance, that 

 volcanoes are situated near the sea, or in islands. It is difficult 

 to give a satisfactory reason for this fact, and still more difficuk 

 to account for the manner in which the communication may take 

 place. There is every reason to believe, that the infiltrations of 

 the sea advance but a very short distance into the interior of the 



