tions have been used as a basis in certain calculations we have made but in the case of malaria we find reliable figures already available. Dr. L. O. Howard has made a very careful and conservative estimate of the loss to the United States due to malaria. His conclusion is that $100,000,000 per year is a fair estimate. The writer's studies have convinced him that this estimate is extremely conservative. If the full effects of the depreciation of land values due to the presence of mosquitoes and the hindrance to development were to be taken into consideration the figures would have to be raised considerably.

Spotted fever causes about fifty deaths per year and there are about four hundred cases of invalidism not resulting in death. On the basis mentioned, the deaths represent a money value of $85,000 and the invalidism $15,000, or a total of $100,000 annually.

Rather exact estimates of the losses due to splenetic fever of cattle have been made. A very reasonable figure which has been practically agreed upon by a number of investigators is $100,000,000 per year.

The other diseases included in the list of those transmitted solely by insects, namely, typhus and dengue, are not covered by absolutely definite statistics at the present time. In case of dengue it is probable that many cases are included in the reports on malaria. Typhus fever is of no great importance although it is probable that a surprising number of cases will be found in the cities that receive a large inflow of immigrants from Europe and Mexico as a recent publication of the Public Health Service shows that Brill's disease is nothing but typhus. In view of the absence of exact statistics it had been considered best to discard these two diseases for the present.

To summarize the losses due to diseases transmitted exclusively by insects, for which statistics are available, we have:

We now proceed to a number of important diseases which are not transmitted exclusively by insects, but by them to a greater or lesser extent. These are: tuberculosis, typhoid fever, enteritis and diarrhea and dysentery. The most important of these is tuberculosis which, according to Professor Fisher's statistics, causes a total loss to the people of the United States of over $1,000,000,000 annually. There are no data available, as far as the writer knows, which would give a definite basis for estimating the proportion of deaths from tuberculosis which are chargeable to insects. Recent work on the longevity

of the tubercle bacillus throws considerable light on the likeliho of insect transmission. It has been found, for example, that t longevity of the organism increases enormously as the environme changes from light and dry to dark and moist. In other words, t highest longevity occurs in exactly such places as are best adapt for the breeding of the house fly. We consider that in all probabili one twentieth of the cases are contracted through the agency of insect We, therefore, have a probable annual loss in the United States $50,000,000 due to insects in connection with tuberculosis.

In the case of typhoid fever, considering that one fifth of the los is due to insects, we have a total of $70,000,000 per year.

In the group of enteritis and diarrhea no estimate of the total los seems to have been made. From the census report covering the year 1900 to 1904 we find that the number of deaths per 100,000 from thes diseases was 112.8. The death loss for the United States, on the basi of life value of $1,700, would be $178,000,000 annually. To this w judge there must be added at least an equal amount of loss on account of invalidism. We consider that one tenth of the loss may be due to insects. This gives a total of $35,000,000 per annum chargeable to insects in connection with these diseases.

In the same way we conclude that the losses due to insects that are concerned in the carriage of dysentery amount to $2,800,000 per year. In making the estimate of the cost of invalidism due to enteritis and diarrhea and dysentery we believe that we are more than conservative. In the cases of the three important diseases; namely, malaria, tuberculosis and typhoid fever, for which statistics are available, the total loss is eight times the death loss, but in these instances we have estimated the total loss as only double the death loss.

We may summarize the losses due to the two classes of insects which we have discussed, as follows:

We are certain that in making our estimates we have leaned far towards the side of conservatism. For the moment we have not considered poliomyelitis, pellagra and several other maladies at all, and other expenses chargeable to insects have been omitted. Take, for

example, the expenses arising from quarantines. The precautions that are taken against the introduction of yellow fever, cholera and other epidemic diseases are large, to say nothing of the expense of the control of plague which is already introduced in this country.

It must also be borne in mind that we are only beginning to acquire definite knowledge regarding insects which transmit diseases. The extent to which this is done in cases where something is known about transmission is probably greater than we believe, and, moreover, we must consider the possible discovery of insect causation of diseases which are not at present included in the category of those borne by insects at all. It was but yesterday that the connection between poliomyelitis and the stable fly was discovered and no one knows what addition to our knowledge will be made tomorrow.

The extent to which the importance of insect disease transmitters seems certain to increase can be realized by considering poliomyelitis. The statistics relating to this disease are very unsatisfactory on account of the apparently great increase in the number of cases within the last few years. The latest statistics available give the deaths from this malady in 1909 as 569 in the registration area of the United States which represented at that time 55.3% of the total population of the United States (Frost Public Health Bulletin 44, page 8). The same authority gives statistics which indicate an average death rate of 7.7% If we estimate the number of cases from the non-registration area in proportion to those in the registration area in the United States (it may be incorrect on account of the greater occurrence of the disease in the northeastern part of the country where practically all of the states are in the registration class), and use the mortality rate mentioned, we find an annual loss for the United States in the value of lives of $1,734,000. The 13,000 cases of invalidism suggested by these statistics would represent a money loss of $10,404,000, or a total from the disease of $12,138,000. If insect transmission transpires to be as important as the work of Brues and others indicate, at least one tenth of the cases may originate through the attacks of Stomoxys calcitrans. This would add over a million dollars annual loss to the estimate we have given.

In all of these estimates we have omitted, altogether, an important. group of incidental expenses that is chargeable to insects. This concerns the warfare that is waged throughout the country against numerous species which are merely nuisances and not, as far as known, concerned in the transmission of diseases. The house fly and various non-pathogenic mosquitoes are combated by various mechanical devices, such as screening, the expense of which, as Doctor Howard has pointed out, probably aggregates ten million dollars annually.

In addition to this charge the amount expended in lotions and such preparations must be very considerable.

AGRICULTURAL AND VITAL LOSSES COMPARED

We are in now a position to compare the losses due to insects which carry diseases with those which affect the crops grown in the United States. The most complete account of the total losses caused by insects to farm products with which we are familiar is that of Mr. C. L. Marlatt in his paper in the Yearbook of the Department of Agriculture for 1904. He estimated a total loss of $795,100,000. Our estimate of the losses caused by disease transmitted by insects is approximately one half as great as that caused to all farm products. It is altogether likely that the actual losses will very nearly equal those occurring with farm products. Surely this is a sufficient argument for greater attention to medical entomology.

A few comparisons are of striking interest. The codling moth, according to Mr. Marlatt's estimate, causes an annual loss in the United States of $20,000,000, or only a fifth of that due to the insects. connected with either malaria or tuberculosis transmission. The loss due to the Hessian fly varies greatly from year to year but is estimated as averaging about $40,000,000, less than one half that occurring in the case of malaria. The damage to all the cereal crops in the United States is only equal to that occurring in tuberculosis and malaria combined, while the damage to natural forests and forest products is estimated to be the same as that in either malaria or tuberculosis.

To obtain a foundation for the comparison we have made we have attempted conservatively to reduce the loss in human life to a pecuniary basis. Although this may have been useful in impressing the point, it really does an injustice to medical entomology. The two branches are radically different in one important respect. One deals with material losses and the other with a reduction in the vital force of the nation. Is it right to compare the loss of a human life with the loss of 28 bales of cotton or 1700 bushels of wheat? The loss in cotton or wheat might be made good in another region or during another season, but for the life that is lost there is no compensation. The recent developments, therefore, bring a new interest into entomology and also give to the entomologist a portion of the respect and honor which has always been given the physician on account of his work in saving and prolonging life.

EXTENT OF PRESENT WORK ON MEDICAL ENTOMOLOGY IN THE

UNITED STATES

We now come to the question of how extensively entomologists in this country have occupied the field of medical entomology. The present membership of this Association is 359. Perhaps a score out of this number, that is, 5 per cent, are more or less concerned with medical entomology. This number includes those who teach medical entomology in connection with other branches of the subject, as well as others who have administrative work on many species affecting agricultural products and minor projects connected with disease transmitting species. In all probability the time put in on the subject by all entomologists in this country who have anything whatever to do with the medical side of entomology would not be more than equivalent to the full time of ten members, or 2 per cent of the Association. We shall consider, however, that an equivalent of full time of 5 per cent of the membership is engaged in this way. It has been pointed out that the losses to the people of the United States caused by insects aggregate at least one half of the losses to agricultural products. On this basis, if entomologists covered the field of medical entomology as thoroughly as they do that of agricultural entomology in this country, there would be 169 engaged altogether in that line of work. Out of 154 projects included in the report of the committee on entomological investigations, only eight deal in any sense with medical entomology. These are distributed over only six states, one of them having two projects of the kind and each of the others one. Could there be a more striking illustration of the neglect of our opportunities?

There is one point the writer desires to make in order to obviate a possible misconstruction of his position. We have compared medical and agricultural entomology and have contrasted the amount of work in each field which is now under way in this country. Much as we urge the necessity of more work in medical entomology, we do not desire to see it undertaken at the cost of a reduction in the work on agricultural entomology. Possibly there are a few cases in which the work on agricultural pests might be curtailed, as, for instance, where stations in neighboring states have similar projects on the same species, but the writer believes in the idea expressed repeatedly by the lamented Dr. John B. Smith, that many men with their different viewpoints might well be employed on the same project, and that there is hardly such a thing as useless duplication in entomological problems. Moreover, one discovery opens new fields. Coquillett's work on cyanogen did not settle the question of fumigation, but led to a host of problems about dosage, plant susceptibility and procedure. The devising of a plan of campaign against a pest leads to the necessity of demonstrations