310 DR DAVY ON THE QUARANTINE CLASSIFICATION OF SUBSTANCES, 



fined, is a great promoter of decay and decomposition, and that no animal sub- 

 stance in a moist state can be preserved free from putridity if subject to putrefac- 

 tion, or defended from change and decomposition, unless atmospheric air be ex- 

 cluded. What should we say of an attempt to convey vaccine lymph to India in 

 a fleece of wool, or in cotton, no precautions having been taken to expel and ex- 

 clude hygrometrical moisture ? It would appear preposterous. Is it not equally 

 so to infer, a priori, that the matter of plague in its unchanged, its active state, 

 can be brought to our shores from those of the Mediterranean in the same vehicles ? 

 And with different degrees of force, according to the quantity of atmospheric air 

 which they may contain, the remark is applicable to almost all the articles brought 

 together under the head of susceptible. 



The distinction in the general classification between hot bread and cold bread, 

 the one being placed in the list of susceptible articles, the other in that of the non- 

 susceptible, seems very characteristic of the ignorant and unscientific manner in 

 which the arrangement has been made, and as if other considerations, besides the 

 mere qualities of bodies, may have weighed on the minds of those who framed 

 the classification. It would have proved very inconvenient to have denounced 

 bread as a susceptible article, as much so as grain ; but not so, hot bread ; it might 

 have been considered a salutary measure, in relation to the general health, to pro- 

 hibit its use. Viewed strictly, however, the rational conclusion is the reverse of 

 that acted on, namely, that cold bread possibly may convey the matter of conta- 

 gion from hand to hand ; whilst the hot bread, in consequence of its heat, would, 

 if it received it, render it inert. The experiments made by the late Dr HENRY 

 went far to prove, that all the contagious matters which he submitted to trial 

 were deprived of their peculiar power by a temperature several degrees below the 

 boiling point of water. 



After the remarks made on the classes of susceptible and non-susceptible 

 articles, it will be almost sufficient to enumerate the articles which have been 

 collected in the third class, or that of objects of a doubtful nature in relation to 

 the conveying of contagion. They are, chiefly, coral in its rough state, elephants' 

 teeth, horns and horn-shavings, drugs and spices of all kinds, coffee and sugar, 

 rolled tobacco, roots and herbs for dyeing, vermilion, newly- wrought copper and 

 its clippings, glutinous fruits. 



The remarks made on the two preceding classes will apply generally to this. 

 The larger number of articles included in it seems better fitted, reasoning analo- 

 gically, to preserve the matter of contagion than to promote its decomposition ; 

 some, by their compactness of texture, excluding air, as ivory, horn, and coral ; 

 others, by their antiseptic qualities, as sugar, and the majority of drugs and 

 spices, arresting change. 



The classification I have commented on is that adopted in the quarantine 

 system lately attempted to be introduced into Turkey under the superintendence 



