when columbus sent his companion miguel dettori to explore the interior of the newly discovered continent he returned with a report that he had seen natives who sat before burning pieces of wood upon which they place dried leaves and then inhale the smoke through tube inserted in their this was the first acquaintance of white men with tobacco the fragrantly is of the indians quickly spread around the world today the labor and skill of thousands of families goes into the growing and processing of tobacco tobacco plants grow on millions of acres of pearl soil soil that might otherwise be used to produce from cure tobacco leaves such generally known product the snuff chewing tobacco pipe tobacco cigars and cigarettes are made more stores sell tobacco than bread and money spent on tobacco can pay for half our schools this then is an example of a product that represents one of america's largest farm crops and one of the most controversial consumer articles what does this product contain and how does it affect those who use it but tobacco smoke contains is simple to determine here is a scientifically designed operators for collecting the content of the smoke under controlled conditions smoking is a process of we mean the transformation of dried substances into a paper supplementary traps battlers catch any substances not collected in the flasks the liquid into the flasks absorbs the nicotine added in the other two flasks and collects the tirade substances out of the burning tobacco from the first group of flasks chemists isolate nicotine by distillation the amount of nicotine obtained in this process is of course small added can only be measured by very delicate instruments provided spectrophotometer for instance is often used to measure minute amounts of nicotine different cigarettes even of the same brand sometimes very in weight and quantity of nicotine variations from one to three milligrams per cigarette have been recorded one milligram is about this much and three times this amount could cause nicotine poisoning the liquid in the second pair of flasks contains tires platform dissolves the tires from the solution then of chloroform and water do not mix the platform mixture separates from the water as soon as the shaking stops finally chloroform is evaporated out of the mixture by boiling leaving the times behind in the measuring cup cigarette tires consist of a variety of substances which can be further separated chemically here are some of the more important constituents of cigarette tires some may be considered irritants other stimulants out of service having no known effect upon the human organism that a small including cigarette smoke contains some carbon monoxide a poisonous gas that combines readily with the hemoglobin of the red blood cells and prevents it from absorbing oxygen in the lungs and giving it off to the tissues very little is known about how much time carbon monoxide from tare substances are the product of burning they are not in the green tobacco leaves but on like tires nicotine is found in the unburned tobacco in smoking some of the nicotine that is the body when we light a cigarette about twenty five percent of the nicotine is destroyed chemically by fire behind the glowing tip in this article tobacco is heated to a medium temperature gases containing nicotine arise from the leaves about thirty percent of these gases pass out into the atmosphere while the remaining forty five percent continue to flow with the main air current towards the mouth however the major portion of the nicotine does not reach the mouth it is deposited on the cold tobacco particles which it passes on the way in consequence only some fifteen percent of total quantity of nicotine enters the mouth nicotine that is the body primarily through the air passages and lungs however some nicotine is dissolved in the saliva of the mouth and swallowed thus reaching the stomach directly the left side of the heart and from there it is rapidly distributed to all tissues of the this is why the smoker feels the effects of smoking at most a soon as he likes the tobacco carried by the blood nicotine reaches the nerve cells where it didn't use is a complex set of reactions the drug acts mainly on three parts of the nervous system on the ganglia or switchboards of the autonomic nervous system at the junction between nerves and the muscle and on the brain itself at these points the nicotine first stimulates the nerve cells then gradually slows down functions and even paralyzes them as a consequence many types of reactions may go on a different rates added at different places in the body simultaneously producing involved and often unpredictable effects effect which vary with each individual animal experiments enable us to observe the action of massive doses of nicotine not the blood vessels in this rabbit's ear and injection of nicotine affects the rabbit's blood vessels dramatically and this experimental set up effect of nicotine from smoking can be measured with special instruments added a small groups arms relatively small amounts of nicotine sensitive instruments can record its effect for instance these thermocouples record the influence of nicotine upon the body temperature in this experiment we see that the skin temperature gradually drops from point eighty on the graph to about sixty five or fifteen points the skin temperature drops because blood vessels constrict under the influence of nicotine and less blood reaches the skin experiments with animals help dramatize the effect of nicotine on the nerve cells of the hyped by applying the drug directly to the exposed nerve are at a time we induce a change in rhythm to understand better what is happening let us look at a schematic drawing and the experiment nicotine was applied at the spot indicated by the arrow and this is one nerve cell called a gang glee and sell nicotine f stimulates the nerve cells then it paralyzes them see how the rabbit's heart first beats slower than speeds up as the nicotine stimulates and subsequently paralyzes the nerve cells of the heart by the nicotine the grass in the middle reproduces the pattern of breathing we've seen that nicotine causes the heart to beat my rapidly and often irregularly we've also seen that nicotine causes b vessels to contract there is a connection between the two when the heart beats faster and pharms more blood through the blood vessels which nicotine has made now or as a result rather pressure increases smoking is container the redneck movement of the intestine continues even after distant from the animal the scribe shows normal we inject nicotine into the solution the reaction is violent this is one reason why doctors often advise patients with peptic ulcers chronic heartburn or spastic intestines to abstain from smoking nicotine also acts upon the central nervous system it stimulates it and produces a quickening of brain activity which creates a feeling of nervousness and excitement this rabbit react calmly to petting and tapping but as soon as nicotine has acted upon it the rabbit reacted the same treatment with convulsions and tremor nicotine that enters the lungs of the smoker spreads rapidly through the body in turn it is excreted in your saliva and sweat after several days that nicotine leaves the body but the urge to smoke on the other hand smoking is not an inborn inherited or natural urge beginners almost without exception find smoking irritating sometimes reactions are quite violent attention of air passages as a well known sound of the many tar compounds in the tobacco smoke we cannot tell with certainty which ones are one cause irritation our way of life makes it necessary for many people to live in their little with industrial smoke and car exhaust add to this the irritation of tobacco smoke and draw your own conclusions experiments with mice are being conducted in several universities scientists suspect that certain constituents in the smoke probably some of the tare substances may cause cancer in the response retore tract especially in the lungs of smokers by smearing tires obtained from tobacco smoke and polluted city air on the skin of mice scientists have already did in inducing cancer in mice research in this area is relatively new observers also point out the high incidence of lip and tongue cancer is found among pipe smokers the increase in heart ailments in recent years alerted medical research to a closer observation of smoking habits of heart patients there seems to be considerable agreement about the effect of smoking upon the human organism but a great deal more work is needed to explain the potentially dangerous effects of smoke  with these facts it must be the decision of each and every individual whether he or she will take the risk of smoking