484 PLINY'S NATURAL HISTORY. [Book XXXI. 



sive dews 92 * a reproductive of blight in corn, and that hoar- 

 frosts result in blast ; of a kindred nature, both of them, to 

 snow. It is generally agreed, too, that rain-water putrefies 

 with the greatest rapidity, and that it keeps but very badly on 

 a voyage. Epigenes, however, assures us that water which 

 has putrefied seven times and as often purified 93 itself, will no 

 longer be liable to putrefaction. As to cistern- water, medical 

 men assure us that, owing to its harshness, it is bad for the 

 bowels and throat ; 94 and it is generally admitted by them that 

 there is no kind of water that contains more slime or more 

 numerous insects of a disgusting nature. Eut it does not, 

 therefore, follow that river water is the best of all, or that, in 

 fact, of any running stream, the water of many lakes being 

 found to be wholesome in the very highest degree. 



What water, then, out of all these various kinds, are we to 

 look upon as best adapted for the human constitution ? Dif- 

 ferent kinds in different localities, is my answer. The kings 

 of Parthia drink no water but that of the Choaspes 95 or of the 

 Eulseus, and, however long their journies, they always have 

 this water carried in their suite. And yet it is very evident 

 that it is not merely because this water is river- water that it 

 is thus pleasing to them, seeing that they decline to drink the 

 water of the Tigris, Euphrates, and so many other streams. 



CHAP. 22. THE IMPURITIES OF WATER. 



Slime 96 is one great impurity of water : still, however, if a 

 river of this description is full of eels, it is generally looked 

 upon as a proof 97 of the salubrity of its water ; just as it is 

 regarded as a sign of its freshness when long worms 98 breed in 

 the water of a spring. But it is bitter water, more particu- 

 larly, that is held in disesteem, as also the water which swells 

 the stomach the moment it is drunk, a property which belongs 



92 ' See P>. xvii. c. 44, and B. xviii. c. 68. 



93 This is somewhat similar to what is said of the putrefaction and 

 purification of Thames water, on a voyage, 



94 " Inutilis alvo duritia faucibusque." The passage is probably corrupt. 



95 See B. vi. c. 27. 



96 Or " mud " " limus." All rivers of necessity have it, in a greater or 

 less degree. 



97 On the contrary, the more the mud and slime, the more numerous the 

 eels, " "Taenias." 



