1895.] MYODES LEMMUS. 58 

That climate, on the whole, affects the death rate amongst 
the emigrants, is undoubted. 
The long period of black frost, which usually occurs in the 
lowlands, they do not meet with in their native resorts. There 
the winter comes on suddenly, and the sheltering covering of 
snow lies compactly over the still unfrozen soil. Just as alpine 
plants in botanical gardens suffer from lasting frost, and re- 
quire to be covered with mats during the winter, so do the 
lemmings feel the unacceustomed cold on the hard frozen and, 
for long, snow-free ground, and this, too, assists in thinning 
their ranks. 
It is remarkable that, notwithstanding they willingly trust 
themselves to the water in order to reach the opposite bank of 
a river or lake, rough and damp weather appears to be injuri- 
ous to them. After å stormy night of wind and heavy rain, they 
are often found lying dead by the hundred in ditches or drains. 
18. *"Lemming Fever.” 
It is obvious that the great masses of individuals which 
perish incessantly during å migratory year, must have an influ- 
ence on sanitary conditions!, especially during the warm season 
of the year. Everyone who has visited the mountain plateaux 
during a great prolific year, will have noticed that their oblong 
pellets of dung are to be found strewed about everywhere, and 
1 An experience already gained in 1532 by Jacobus Ziegler (see p. 6). 
Olaus Wormius, gives (1653) such a disease its name and its dia- 
gnosis in the following words: — 
* Præter enumcrata ab Qlao Magno morborum genera etiam peculiaris 
quedam lues, Norvegis *Leemands-Soet” dicta, eos corrwpit qvi harum 
bestiarum mactationt et expulsiont se dedunt. Ex fætore pessimo infectus 
aer et inspirationi attractus, brumali potissimum tempore, glandularum in 
collo intumescentiam procreat, conjunctam cum wvocis raucedine, impedita 
deglutitione. Hic tumor ettam bubones aæillis et ingvmibus, aliisq. in 
locis habet socios ...” (Olaus Wormius, Historia Animals, &c. Haf- 
niæ 1653, p. 62). 
