484 
PLINX's FATUEAL HISTOBT. [Book XXXI. 
sive dews^^* a reproductive of blight in corn, and that hoar- 
frosts result in blast ; of a kindred nature, both of thenj, 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^^ 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 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. 
AVhat water, then, out of all these various kinds, are we to 
look upon as best adapted for the human constitution ? Dif- 
ferent kinds in difi'erent localities, is my answer. The kings 
of Parthia drink no water but that of the Choaspes^^ or of the 
Eulseus, and, however long their journies, they always have 
this water carried in their suite. And yet it is yoyj 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 IMPUEITIES OF WATER. 
Slime^^ is one great impurity of water : still, however, if a 
river of this description is full of eels, it is generally lo®ked 
upon as a proof of the salubrity of its water ; just as it is 
regarded as a sign' of its freshness when long worms^^ 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 
9-* See B. 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. 
9« 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." 
