T H E D U B L I N JOURI AL OF

M E D I C A L SCIENCE.

DECEMBER 1, 1910.

ORIGINAL

PART I.

COMMUNICATIONS.

ART. X V I I . - - T h e Phys io log i ca l E]~ects o/ A lcohol .a By W. H. THOMrSON, M.D., Sc.D., F.R.C.S. Eng., Dipl. Ment. Dis., King's Professor of the Institutes of Medicine in the School of Physic in Ireland, Trinity College, Dublin.

THe, subject of " Intemperance" is a comprehensive one, and needs limitation. From meaning " inobservance of the proper measure in regard to any action," it has come to signify " habitual over-indulgence in the u, se of in- toxicating liquors." I have no doubt that this is the meaning attach,ed almost instinctively by every one now to it. But let us remember that the term has not wholly lost its general significance, and that there are other forms of intemperance almost, if n,ot quite, as blame- ~or thy as alcoholic intemperance. And above all, let us aim at temperance in our consideration of the subject of intemperance, so that we may dispassionately and without bias ascertain the facts so far as we are able to review them.

�9 Read at a Mee t ing of t he C h u r c h of I r e l and Conference held in Belfas t , October l l t h - 1 4 t h , 1910.

VOL. C X X X . - - N O . 468, THIRD SERIES. 2 D

418 The Physiological E]~ects o~ Alcohol.

And here let me premise at the outset that I am not speaking to. you as a total abstainer.

The question of the influence of alcohol on the human organism is a very wide one. We could not possibly examine all its phases, even in the whole of the time allowed to the work of this meeting. We shall, there- fore, have to select, and rapidly get, or t ry to get, to the kernel of things. I propose, therefore, to ask you to con- sider with me the following points : -

Can alcohol be in any sense regarded as a food, and i2 so, what are its specific effects and limitations ?

Wha t influence does alcohol exert on the organs which digest it, and on the digestion of other 2oods?

Wha t effect do,es Mcohol produce on the organs of cir- culation ?

Wha t action has alco.hol on the brain and its functions ? Lastly, what is the dietetic effect of alcohol in small

quantities ? To take the first inquiry-- Is alcohol a food? Wha t

constitutes a ~ood? A food is something which yields energy to the body. How does a food yield energy to the body? By being slowly oxidised or burnt within the system. I t is in a similar, though much cruder way, that coal yields energy to the steam engine o,r petrol to the motor engine viz., by being oxidised or burnt. The heat of burning in the former case is transformed through the medium o2 steam into mechanical work. Now we know that different coals have different heat values, and consequently different energy values. Similarly with foods : d.ifferent kinds have different energy values. Fats and oils, for instance, have, weigh~ for weight, more than doubl.e the energy value of sugar and starchy foods. But our capacity for using fats and oils is very limited, and consequently but a small proportion of the total energy required in the system is supplied by them.

We may now deal with alcohol. 12 it is oxidised or burnt in the body, in a similar way to ordinary foods we must consider it a food. But it is necessary to be very

By I)a. W. I-I. THompson. 419

sure before we can decide one way or the other. I t is known that many things pass through the body without being changed or oxidised, and without liberating energy. ~s this the case with alcohol or not? Well, possibly if we relied solely on the evidence of our olfactory organs we should say that alcohol comes out in vapour un- changed. But when accurate measurements are made it is found that the proportion of alcohol which ]eaves the body unchanged is extremely small : seldom above 2 or 3 per cent. of the quantity taken, and often no~ more than 1 per cont., even when the allowances exceed three, ounces daily. By far the greater proportion is oxidised to carbon dioxide and water, just as .occurs in the case of sugar and fat, or as in the case ,o,f coal or petrol in the engine. In passing, I may say that sugar itself is closely allied to an alcohol, though one .of a much more complex nature than spirits of wine or ethyl alcohol, as w.e term the latter scientificMly.

We must, therefore, accept it from this line of evi- dence, that alcohol has food properties, that it is oxidised in the body, and is capable of yielding energy to it. Moreover, its energy value i,s high--considerably higher than sugar, though not so high as ~ats. The relative vahes are--Sugar, 4; fat, 9; alcohol, 7.

But there is another touch,stone wherewith to test the value of any substance as a food--namely, by ascertain- ing whether it can replace other articles in the dietary, such as .starch, sugar, or fats ? Can alcohol be utilised by the human body so as to save othex elements of the food or its own tissues from be4ng burnt Or oxidisod ? The ex- perimental investigation ,of this question is one requiting great technical skill, and the, results of the, earlier inves- tigations are conflicting; but more recent experiments, carried out with painstaking care, have settled conclu- siyely that alcohol does save other food substances, notably" fat, from combustion; and therefore from this second point of view it must al.so be assigned nutrient properties. I t is a well-known fact that the habitual use

420 The Physiological E~ects o] Alcohol.

of alcohol frequently promotes an accumulation of fat in the body. Par t o2 the explanation of this is that the alcohol i,s oxidised, leaving the fat to be stored up.

We have, therefore, to take it as proven that alcohol is oxidised in the body, and yields energy to it. Further, it is able within limits to replace other non-nitrogenous foods, such as starch, sugar, and fats.

But admiring all this, as we are compelled to do from the scientific evidence, we have still to ask, Is it a desir- able or suitable food .9 Can it be taken without injurious effects to the organs and tissues concerned with its diges- tion and utilisation in the human body.9

This practically covers the ground oi the second question asked at the outset, and in answering it we must keep to firm, unassailable ground. By this I mean that if our answer refers to the consumption of quantities that would produce any of the outward evidences of in- temperance--or even to the habitual use of lesser quan- tities in the case of many. individuals--then it is un- doubted that the .organs concerned with its absorption become impaired.

I t is also quite certain that the resistance of the body generally to the inroads of disease is lowered. Hospital records infall ibly show this, particularly in regard to pneumonia and to cholera in countries where it is prevalent.

I shall return before closing my remarks to the dietetic use oi alcohol in strictly moderate quantities. Mean- while I must rapidly touch upon its effects on the heart and circulation, and here again we must dispassionaboly look at both sides. Very reliable investigations have been carried out, which show that in extremely small quan- t i t i e s - n o t exceeding 0.2 per cent. of the circulating blood--it exerts a nutrient and sustaining effect upon the heart. Medicinally administered in certain cases it also promotes the circulation and nourishes a flagging heart, so that, so far as can be judged, recovery has been pro- moted or life saved by its use. On the other hand, i~ thr

By DR. W. H. TtIoMesoN. 421

dose exceeds a very small percentage, it rapidly becomes injurious, and when it reaches a strength of 0.5 per cent. of the circulating blood the substance acts as a poison.

I t may be, intexesting to state that there is a hypothesis - -and not an improbable one--based on evidence, to which I need not refer, that sugar and starches pass through various transformations before being utilised ?o furnish energy to the muscl.es and other organs of the body, and that the final stage immediately before oxida- tion is alcohol.

But, however this may be--and so long as it is an hypothesis w.e need not seriously consider i t - -we do know for certain, that the prolonged use of alcohol tends ~o bring about structural changes in the heart and blood vessels, which impair the circulation and shorten life.

Now let us turn to its effects on the brain. Alcohol is commonly regarded as a stimulant ~o the functions of the brain, but in animals it acts as a pure depressant, and in ma~ it is, perhaps, not sufficiently recognised how often this, and this alone, is the effect produced.

Thos'e cases in which apparently the opposite effect occurs--namely, stimulation, as shown by exhilaration and loquacity--attract mere attention, but are probably less frequent.

One of the unquestioned effects of alcohol on the brain is that it removes restraint, so that the more recently acquired and higher mental faculties are for the time being blotted .out, whereas the mechanical and more automatic functions remain intact. Hence the saying, ~n vino ~eritas, the inward man being revealed. This suppression of certain functions, be~gtnnin~ with the highest, is the feature of the effect of alcohol on the brain. That is to say, it is probably not an excitant at all, but s.imply a depressant, and acts by removing the bonds of restraint.

The depressing effect of alcohol is also shown by the fact that it causes an earlier onset of mental fatigue. This has been tested in various ways; for example, in

422 The Physiological EHects o/ Alcohol.

compositors by the amount of work done, and the propor- t ion of mistakes made, as shown on days a f te r alcohol had been taken overn ight as compared with normal days. L e a r n ing by heart , and the per formanee of exercises in addi t ion and mul t ip l icat ion, were also exper imenta l ly proved to be more difficult af ter alcohol than before. At ten t ion and accuracy of a im were likewise impai red as shown by the number of fai lures to touch in succession a series .of dots on a roll of paper rap id ly drawn th rough a slit before the observer.

W e come last ly to the dietetic, use of alcohol. This is not a subject for labora tory investigations, since i t re- quires prolonged observations. There are, however, c~r- tMn cases in which alcohol increases the taste, for food, and in small quant i t ies promotes digestion. I t also appears to be t rue tha t some people can take alcohol in moderate quant i t ies and di luted condition, such as in the form of l igh t wines, beer, cider, and s imilar beverages, wi thout apparen t de t r iment , for the grea ter pa r t of the i r lives. B u t people va ry very much in this respect, W h i l e some can do so, others cannot : while some can remain content with small quanti t ies , others cannot re- main so, and herein lies one of the gl~eat drawbacks to the habi tual use Omf alcohol. One thing, however, appears to be ce r t a in - -name ly , t ha t alcohol is not a necessary par t of the d ie tary of any one, nor even is it necessary as a remedial measure in the hands of the physician.

Before closing I should like, to re la te an inc ident which I witnessed dur ing the past summer, and which may serve to point the moral of my remarks. On a somewhat s imilar occasion to this, a Cont inental surgeon of world- wide reputa t ion , speaking on the subject of the use of alcohol, said, to the momenta ry surprise of every one : - - " I am a grea t bel iever in alcohol. I use large quant i t ies o.f it, and I a t t r ibu te my success in g rea t measure to this fac t ; bu t I always use it ex ternal ly , and I never use it i n t e rna l ly . "