Gr. H. F. Nuttall 
433 
good margin of safety under working conditions Captain Orr adopted an 
exposure at 60-65° C. for 15 minutes as adequate. Grant and Peacock 
recommend an exposure at 65° C. for 30 minutes. 
2. Moist Heat. 
(a) Immersion in hot water. 
The following table summarizes the results of experiments conducted 
by various authors and myself: 
Time of 
(a) Experiments with Nits. 
Temperature ° C. 
exposure in 
Result 
Authority 
immersed in 
minutes and 
+= killed 
(reference 
water 
seconds 
0 =survived 
see p. 435) 
100° 
5" 
+ . 
Kinloch 
98-4° 
30" and 60' 
' + . 
Bacot 
O 
00 
00 
15" 
+ 8 nits, collapsed after 20' ... 
Nuttall 
76° 
30" 
+ 4 nits, collapsed and opaque ... 
99 
o 
O 
I> 
10" 
+ 21 nits, clouded, many shrunken, all col¬ 
lapsed in 24 hours controls hatched) 
99 
67° 
1' 
+ 4 nits, slightly opaque 
99 
05 
O 
o 
5' 
+ 4 nits, „ „ 
99 
o 
O 
O 
5' 
+ 4 nits, opaque, soon dried up 
Widmann 
55° 
10' 
+ 3 nits ... 
99 
55° 
30' 
+ . 
Bacot 
54 c 
10' 
+ 4 nits, appeared unaltered ... 
Nuttall 
50° 
15' 
+ 3 nits ... 
Widmann 
45° 
15' 
O 3 survived and hatched in 71 days 
99 
40° 
1 day 
(b) 
O 2 survived and hatched in 7 days 
Experiments with Active Stages. 
99 
100° 
V 
+ stage or number not stated 
Galli-Valeric 
70° 
10" 
+ 1 $ 2 5 turned red in 1 hr, dried up in 24 hrs Nuttall 
50° 
30' + second stage larvae... . 
(c) Exposure recommended by authors in practice. 
Purpose 
Bacot 
Water +10.% 
soda, boiling 
Water + soda, 
2 hrs 
for underclothes [heroic and no mistake] 
Izar 
boiling 
15' 
for underclothes . 
Heymann 
Water at 100° 
15' 
99 99 *•* 
T9 
Water at 100° 
5' 
kills nits and lice [certainly sufficient] 
Peacock 
Water at 100° 
a few' 
for brushes and combs harbouring capitis [will 
scarcely improve brushes] 
Greene 
Water at 35° 
— 
for bath water, supposed to kill lice [nonsense] Klemperer 
and Zinn 
The foregoing results, coupled with other experiments of my own 
which were not protocolled, indicate that active stages and nits are killed 
