As   a   rule,   field   crew   members   should   be familiar with the telephone number and location of the nearest hospital or dispensary their party will  be  operating,  should  have  a  transport  vehicle available and ready, and should have valid govern- ment  vehicle  operator’s  licenses.  In  addition,  a first-aid  kit  should  be  kept  handy  at  all  times. PROTECTING  AGAINST WEATHER   HAZARDS For all weather hazards, the best preventive measure  is  the  wearing  of  adequate  protective clothing.  When  the  weather  is  cold  enough  to cause frostbite, wear a hat that covers your ears, gloves  or  mittens  for  your  hands,  and  cold- weather  footgear  for  your  feet.  These  are  the primary  areas  most  subject  to  frostbite.  Wear  a hat also when there is danger of heatstroke. Unless or until you are immune to sunburn (by tanning), keep  your  skin  covered  against  the  sun.  Fair- haired  or  sandy-haired  individuals,  even  when they  tan,  may  be  susceptible  to  a  form  of  skin cancer caused by exposure to sunlight. If you are in  this  category,  you  should  keep  the  skin  covered whether you  “tan”   or   not. Two very common weather hazards, frostbite and heatstroke (commonly called sunstroke), are fully covered in the Standard First Aid Training Course.   Lesser  weather  hazards,  such  as  the exposure caused by wearing insufficient clothing in cold or wet weather and the possibility of a bad sunburn  in  hot  weather,  are  not  mentioned. In  general,  when  you  set  forth  with  a  field party, wear or carry with you clothing that will provide  adequate  protection  against  the  weather— not just as it is at the time you set forth, but as it  may  possibly  develop  before  you  get  back. RECOGNIZING  AND  AVOIDING POISONOUS REPTILES AND INSECTS As a general rule, it is best to assume that all reptiles of the snake family found in the United States and overseas and that all insects you can’t recognize  as  poisonous  MAY  BE  poisonous. The poisonous snakes of the North American continent  belong  to  the  viper  family.  The distinguishing characteristics of a viper area flat head and a thick body. The most common North American   viper   is   the   RATTLESNAKE.   All rattlesnakes are distinguishable by a row of hard rings,  called  rattles,  on  the  tail.  The  snake  makes a  hissing  sound  with  them  when  it  is  angry  or alarmed.  The  banded,  or  timber,  rattler  of  the northeastern  United  States  is  smooth,  silver  gray in color. The diamondback rattler of the United States Deep South is silver gray with a diamond- shaped pattern on the skin. The western diamond- back rattler has the same diamond pattern, but is  a  copper  color.  The  red  rattler  of  southern California  is  a  deeper  copper  color. Besides  the  rattlesnake,  the  most  common North American poisonous snake is the WATER MOCCASIN,  sometimes  called  the  cottonmouth because of a white mouth lining that the snake exposes when preparing to strike. The skin of the water moccasin is dark brown with black bars on the upper side and black blotched with yellowish white on the under side. The  reddish  brown  COPPERHEAD  has  no rattles. This viper is found especially in uplands of the eastern Unites States. The most common poisonous insects encoun- tered in North America are the BLACK WIDOW SPIDER,  the  TARANTULA,  and  the  SCORPION. The  black  widow  (which  may  be  encountered  any- where in the United States) is recognizable by its small, shiny black body. The tarantula is a long- legged, hairy member of the spider family, found chiefly in and close to Texas. The scorpion, found mainly  in  the  semitropical  parts  of  the  United States, resembles a lobster or crawfish in shape. The  symptoms  that  develop  from  the  bite  of each  of  the  reptiles  and  insects  mentioned, together  with  the  appropriate  first  aid,  are thoroughly  described  in  the  Standard  First  Aid Training   Course,   NAVEDTRA   10081   (latest edition). AVOIDING  OR  TREATING POISONING  FROM  POISONOUS PLANTS The Standard First Aid Training Course con- tains  an  extensive  section  on  a  variety  of  poisons. However, it does not mention a type of poisoning to  which  survey  parties  are  particularly  exposed— poisoning resulting from contact with poisonous plants. Poisoning of this kind is not likely to be fatal  (although  it  can  be,  under  certain  circum- stances), but it can cause you a lot of misery and considerable  reduction  in  on-the-job  efficiency. The  most  common  poisonous  plants  in  the United  States  are  POISON  IVY  (including  a variety called poison oak) and POISON SUMAC, both   of   which   occur   everywhere   in   North America.  These  plants  contain  and  exude  a resinous  juice  that  produces  a  severe  reaction when it comes into contact with the skin of the average person. The first symptom of itching or a burning sensation may develop in a few hours or  even  after  5  days  or  more.  The  delay  in  the 12-28