Armored 
Medical Research Laboratory 
Fort Knox, Kentucky 
Report On 
PROJECT NO. 22 - TEST OF HAMMOCK* JUNGLE, IMPREGNATED WITH 
"PREVENTOL G-4" 
28 December 1943 
Project No, 22 RESTRICTED 
ARMORED MEDICAL RESEARCH LABORATORY 
Port Knox, Kentucky 
■Project Noc, 22 
File Noo 727-3 GNOML 
2B December 43 
1. PROJECT: No© 22, Test of Hammock. Jungle. Impregnated with 
"Prevent©! 
a© Authority for Test: Reference, 1st Indorsement, Headquarters 
Army Ground Forces, File 427A?.November 1943) GNRQT-6/60280, dated 
17 November 1943, subject: Hammock, Jungle. 
bQ Purpose - To determine whether dermatitis or other skin 
reactions result from the us© of Hammocks, Jungle, Impregnated with "Preventol 
G-4", under simulated Jungle conditions. 
2. DISCUSSION; 
a. Because a number of cases of dermatitis occurred in women 
working with canvas impregnated with the anti-mildew agent "Preventol G-4W, 
hammocks similarly impregnated were tested to determine whether dermatitis 
occurred in soldiers sleeping in them© 
b0 Tests were of two types; 
Patch tests: These were done initially for primary skin 
irritation on 112 men and later for skin sensitization on 95 menc In 10, 
the patches were applied during a routine acclimatization test in the Labora- 
tory Hot Room. In the remainder, the subjects were tested while on routine 
company duty. In 15 men, (l) canvas, (2) netting and (3) rubberized rain- 
proof cover were each used for patch material. In the remainder only the 
canvas of the hammock was used since this was the material in most intimate 
contact with the skin© 
Sleeping tests: These were carried out on 12 subjects who slept 
in the hammocks a total of 95 man-nights. For details, see Appendix A. 
Co Diet, general health and irritants will influence the behavior 
of the skin with respect to sensitizing agents© The results of these experi- 
ments may therefore, be accepted as applying only to military personnel who 
are exposed under like circumstances© In the absence of any evidence of 
primary irritation or sensitization in these tests, one may, however, antici- 
pate only minimal effects even under the most unfavorable circumstances. 
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3. CONCLUSIONS; 
No dermatitis which could be attributed to the hammock 
developed in any subject* There was the usual prickly heat and scattered 
papular eruption on the thigh, abdomen, groin and buttocks which is almost 
universal in men living in hot environments. These lesions were notably 
prevalent in areas covered by shorts, and thus not directly exposed to 
hammock surfaces0 
b. In 112 men to whom patch tests wer$ applied, there was no 
instance of irritation or erythema with initial contacts of 24 or 4& hours* 
In the 9$ on whom a second patch was applied in the same spot 10 days after 
the first there were no sensitization reactions* 
4o RECOMMENDATIONS; 
a0 Hammocks, Jungle, impregnated with "Preventol G-4n be con- 
sidered safe for use so far as danger of dermatitis is concerned* 
b. Tensile strength of the end spreader-ropes in saturated atmos 
pheres be checked for adequacy. 
Prepared by: 
William B* Bean, Capt0, MoC* 
Ludwig W. Eichna, Capt., M.C0 
William Fo Ashe, Major, M0Co 
APPROVED 
WILLARD MACHLE, 
Colon®!, Medical Corps, 
Commandingo 
2 Incise 
#1 - Appendix A 
#2 - Table I 
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APPMDU A 
BXPEamSWtAL conditions and procedures 
1, Fateh TestsD 
a. Tests Tor contact dermatitis (112 men) and sensitivity 
reactions (95 men) were conducted on two groups of men, divided as follows; 
(1) QRCXJP I* Preliminary studies were made on 15 soldiers 
from the Armored Replacement Training Center with 3 
materials, (a) canvas, (b) netting and (c) rubberized 
shelter material—all taken from a hammock impregnated 
with "Prevent©! G-4" furnished by the Office of the 
Quartermaster General from the Philadelphia Quartermaster 
Depot* Ten of these men were tested in the hot room 
where they had been living for from 3 to A weeks in a 
simulated Jungle environment, they were retested for 
sensitivity 10 days later* 
(2) GROUP II* Since no reactions occurred in Group I, patch 
tests using hammock canvas only were conducted on 97 
additional soldiers, selected at random from Headquarters 
Company, Armored Conrnand* 
b. Round patches 7/8 inch in diameter were applied to the skin of 
the back, or the upper arm below the vaccination scar* Commercial patch test 
holders, adhesive plaster or cellulose tape were used to affix the patches. 
The skin exposed to the test material was examined 24 and 48 hours after 
exposure. Ten days after the initial application of the patch, a second one 
was applied to precisely the same site in 95 men to see whether sensitization 
of the skin had occurred. The skin was reexamined after an exposure of 48 hours 
2* Hammock Tests. 
a. Environment* 
(1) Mon lived in the Laboratory Hot Room in which the dry bulb 
temperature was maintained as close to 90°F as possible 
and the wet bulb temperature regulated to give a relative 
humidity approximately 95$ from 0800 to 1700 hours* During 
the night the dry bulb temperature approximated 84°P with 
the relative humidity 70-75$» No radiant heat was supplied. 
(2) Pilot tests were made early in November 1943 with men who 
had been acclimatized to this environment. No skin 
reactions followed patch tests (15 subjects) or sleeping 
in the hammock (4 subjects). A special test group of 8 men 
was then followed for two weeks in the hot room during the 
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latter part of November 1943 * The men lived in the hot 
room continuously except for 10-minute clean-up periods 
in the morning and evening, A 24-hour leave was given 
for Thanksgiving Day0 
bo Experimental Subjects, 
(1) The twelve enlisted men, 19-24 years of age, volunteered 
to sleep in the hammocks. They were of varying builds, 
and came from different parts of the country. Two were 
red-headed, 9 were fair skinned and blond, and 1 was darkj 
a selection which insured having many subjects with sensi- 
tive skin, 
Co Clothing. 
(1) Men wore suits, two-piece, HBT during the day except for 
three days when shorts were worn. In the hammocks, at 
night, only cotton shorts were worn, permitting exposure 
of large portions of the skin to the fabric of the hauanock 
d. Activity. Food, Water. 
(l) usually walked a distance of 12-1/2 miles a day in the 
hot room and were acclimatized according to the procedure 
outlined in a previous report (Project No0 2 - Operations 
at High Temperatures, 2-7, 11, 13, 15, 17, 19, dated 
18 October 1943)* They ate regular array garrison rations. 
All drinking water had salt added to a concentration of 
0ol*o 
«* 
e0 Sleep Rout ins0 
(l) Men spent the night in the test hammock. Eight to nine 
hours were scheduled for sleep. For the first three 
nights most men slept not more than half the time, but 
later all men were able to sleep comfortably for eight 
hours. The hammocks were suspended from hooks set 11 feet 
apart and there was considerable discomfort from bending 
the body and other troubles associated with learning to 
use the hammocks, (See Table I) 
RESULTS 
1* No skin rash, reaction or dermatitis which suggested a specific 
contact dermatitis appeared in the experimental subjects sleeping in the 
hammock. Jungle, impregnated with "Prevent©! G-4". Prickly heat of varying 
degrees of severity occurred in most subjects. It was located in regions 
subjected to nibbing by clothing on skin or by one skin surface on another 
and appeared in its worst form over the skin of the crotch which was covered 
by shorts and was not exposed directly to the hammock. In previous jungle 
tests, a similar skin condition has been the common experience of men who 
APPENDIX 
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slept in unimpregnated hammocks or on canvas cots in the hot room; or 
outside the hot room, but worked in it during the day, 
2„ The patch tests gave no indication of contact irritation or sensitivity 
to the hammock fabric, 
3o The end spreader ropes of several hammocks broke while men were sleep- 
ing in them, suggesting the possibility that "Preventol 0-4" may have adverse- 
ly affected the ropec 
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APPENDIX A 
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OBSERVATIONS ON 8 KEN SLEEPING IN HAKKOCKS 
IN JUNGLE ENVIRONMENT 
Date 
Approximate 
Hours Sleep 
(Average) 
Miles 
Walked 
Non-specific Skin Reactions 
to Heat and Sweat 
Hammock 
Rashes 
Nov, 18 
4 
10 
2 men with prickly heat 
None 
Nov. 19 
5 
izh 
3 men with prickly heat 
None 
Nov0 20 
12^ 
(Shorts) 
6 men with prickly heat 
None 
Nov. 21 
7 i 
5 
Prickly heat about same 
None 
Nov0 22 
8 
12* 
Prickly heat about same 
None 
Nov. 23 
8 
I2i 
Prickly heat about same 
None 
Nov. 24 
8 
12* 
Prickly heat improving 
None 
Nov. 25 
- 
- 
Out of roan for Thanksgiving 
- 
Nov. 26 
8 
12* 
Slow improvement in prickly 
heat with occasional relapse 
None 
Nov. 2? 
. 8 
12* 
Slow improvement in prickly 
heat with occasional relapse 
None 
Nov. 28 
8 
12* 
Slow improvement in prickly 
heat with occasional relapse 
None 
Nov. 29 
8 
12* 
Slow improvement in prickly 
heat with occasional relapse 
None 
Nov. y& 
- 
12^ 
Slow improvement in prickly 
heat with occasional relapse 
None 
Hrs* Exposure && 
Hrs. Sleep 79 
TABLE I 
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