278 French National Institute. 



modifications of which it is susceptible. M. Halle has 

 communicated to the Institute some very interesting observa- 

 tions upon the irregularities which the vaccine inoculation 

 has undergone at Lucca in the course of 1806. 



These differences did not affect the progress, the periods, 

 nor the essential characters of the vaccine eruption. 



They were manifested in the form of the pimple, which, by 

 extending and confounding itself with some small pustules 

 round the principal one, lost both its regular form and the 

 umbilical depression, which it presented at the moment of 

 its formation. 



I«a the nature of the crust which succeeds the pustule, 

 the latter had not the brown shining colour of the crust of 

 the common vaccine ; it was irregular in its form, like the 

 pimple which had given birth to it, and left in the skin a 

 hollow, which afterwards filled up completely. 



Finally, eruptions of pustules over the whole lodij were 

 seen at the moment the areola was formed around the prin- 

 cipal button. 



These irregularities were epidemical throughout the whole 

 territory of Lucca. 



The counter proofs made by sniall pox-inoculation upon 

 individuals who had exhibited these irregular symptoms of 

 vaccine, demonstrated that their irregularity had in no mea- 

 sure altered the preservative properties of vaccine. 



The third branch of natural history, that which treats of 

 minerals, has been recently enriched with a most interesting 

 fact. 



M. Vauquelin has discovered the presence of platina iti 

 the famous silver mines of Guadalcanal in Estremadura. 



This metal had only been found in Peru hitherto, where 

 it is combined with a multiplicity of different substances. 

 \n those of Guadalcanal, it is alkjyed with silver, copper, 

 antimony, iron, arsenic, lead and sulphur. It sometimes 

 forms a tenth of the mass. 



The same chemist has made some very important experii- 

 ments upon the refining of iron ores. 



France, although poor with respect to precious metals, 

 compensates for this tjeticicncy in the quantity of fine iron ; 



but 



