est het ists ▁for ▁the ▁armed ▁services . ▁His ▁research ▁included ▁ha z ard ous ▁experiments ▁to ▁test ▁life ▁jack ets ▁( imm ers ing ▁E ▁A ▁P ask ▁in ▁a ▁wave ▁tank ▁while ▁an a est het ised ), ▁the ▁provision ▁of ▁res pi rable ▁atmos pher es ▁in ▁sub mar ines ▁and ▁surv ival ▁during ▁par ach ute ▁descent ▁from ▁high ▁alt itudes . ▁ ▁Mac int osh ▁designed ▁equipment ▁that ▁now ▁be ars ▁his ▁name : ▁a ▁l ary ng os cope , ▁an ▁an a est h etic ▁v apor iser , ▁sp ray ▁and ▁end ob ron ch ial ▁t ube . ▁The ▁l ary ng os cope ▁he ▁designed ▁in ▁ 1 9 4 1 ▁remains ▁the ▁most - used ▁today . ▁It ▁was ▁developed ▁from ▁a ▁Bo yle - D av is ▁mouth ▁g ag , ▁used ▁for ▁tons il lect omy . ▁Mac int osh ▁noted ▁that ▁this ▁mouth ▁g ag ▁indirect ly ▁elev ated ▁the ▁ep ig l ott is ▁and ▁exposed ▁the ▁l ary n ge al ▁a pert ure . ▁ ▁Mac int osh ▁studied ▁un exp la ined ▁death s ▁that ▁occurred ▁under ▁an a est hes ia ▁and ▁established ▁a ▁training ▁programme . ▁He ▁travel led ▁widely , ▁giving ▁demonstr ations ▁of ▁" safe ▁and ▁simple " ▁an a est hes ia . ▁ ▁Mac int osh ▁married ▁Dor othy ▁Mann ing , ▁whose ▁sister ▁Mary , ▁was ▁married ▁to ▁Arch ie ▁For bes . ▁ ▁Hon ours ▁Mac int