in the acidity of the cell sap of living plants above that of the surrounding medium, observed under the same conditions, is due to some property inherent in the living condition.

When dead cells are placed in a solution of KHCO, or NaHCO, of the same concentration used for living cells, the pH of the sap (containing free CO2) becomes that of the surrounding solution (7.8). When the CO2 has been removed, the pH of the sap is 8.8 to 9.0 (that of the surrounding medium without CO2). This process is similar to that which occurs in the case of dead cells placed in sea water containing CO, (Fig. 2).

When living cells are placed in any of the sea-water solutions containing CO2 or bicarbonates, there is apparently a membrane hydrolysis which results in the penetration of H,CO,, to which protoplasm is easily permeable, in advance of KOH or NaOH, which are retarded presumably by the cation. Subsequent slow penetration of these alkalies brings the pH of the cell sap to that which it would have become had the salt itself penetrated as such.

In the case of dead cells, the fact that the H-ion concentration of the sap never exceeds that of the surrounding solution may be due to the fact that basic ions can penetrate freely into dead cells, so that no membrane hydrolysis occurs; or it might possibly be due in part to the fact that there is more available base present in the sap of dead cells than in that of living cells; since the amounts of acid which must be added to sap from living and dead cells to produce a given change of the pH is less in the case of the former than in the latter.

Jacobs (2) noted the increased acidity produced in cells exposed to solutions containing CO2, but failed to detect such a change in cells placed in solutions not enriched with free CO,. He used three solutions, one containing free CO, in distilled water, one containing free CO2 in a 0.5 M solution of NaHCO3, and one a 0.5 M solution of NaHCO3. The cells used were the petals of Symphytum peregrinum, which are blue when alkaline and pink when acid. When they were placed in either of the first two solutions they became pink, but in the third they turned gradually greenish. This latter reaction was interpreted as being due to the action of alkali. In the experiments of the writer, CO, penetrates from a solution of NaHCO, in sea water. No free CO, had been added to this solution, but owing to the presence of bicarbonates, a certain amount of this was present. Evidently the indicator of the plant used by Jacobs was not sensitive to changes in pH over the whole necessary range and, therefore, under the conditions just described, it gave no evidence of the penetration of the acid. It would be of interest to know the pH range over which this indicator is sensitive. In the experiments of the writer, the increased

acidity due to penetration of CO, is followed by an increase of alkalinity. Perhaps the green coloration of the petals of Symphytum observed by Jacobs was also due to increased alkalinity following a stage of increased acidity which was due to penetration of CO2, but which was too slight to affect the color of the natural indicator.

It will be noted that the pH of CO2-free sap of living cells increased in all the solutions in the above experiments. The question arises as to whether the alkaline ions which are presumably responsible for this effect are normally able to penetrate the cell or whether the existence of abnormally high H or HCO, concentration in the cell sap is capable of increasing the permeability of the cell to alkalies. TABLE I.-The effects of several anions upon the rate of change in pH of the CO-free sap of Valonia when K and Na are used.

To obtain more light on this subject, plants were placed in equimolecular solutions (0.03) of K and Na as follows: citrate, acetate and chloride. Table I shows the results. In every case there is a more rapid increase in the degree of alkalinity in the CO2-free sap in the case of K than of Na; but none of the substances studied produces so great a degree of alkalinity as do the bicarbonates. It seems, therefore, that the free CO2 has some influence upon the rate of penetration of these two substances. The fact that CO, penetrates the cell more rapidly from KHCO, containing solutions than from those containing NaHCO, shows that under these conditions the cation affects the permeability of the protoplasm to either itself or to other ions. The same considerations show that the increase in alkalinity of the CO2-free sap may be due either to a selective permeability of the protoplasm, to potassium ions, or to an effect of the increased proportion of potassium upon the permeability of the cell to incoming basic or outgoing acidic ions.

Further experiments on cells placed in solutions of NaOH, KOH, or NH,OH in sea water do show that only the last is capable of penetrating in an appreciable time. The pH of the solutions was in each case 10.0 to 11.5.

These studies may be significant as clues to an explanation of the excessive proportion of K over Na in the sap of Valonia. Further experiments are in progress which may throw more light upon the relative importance of the different ions affecting the permeability of Valonia.

SUMMARY.

Living cells of Valonia ventricosa are exceedingly permeable to carbonic acid. When they are placed in sea water containing alkali bicarbonates, a membrane hydrolysis occurs, carbonic acid entering the cell rapidly. At the same time there is an increase in the alkalinity of sap freed from CO2, presumably due to the penetration of alkali ions. The addition of KHCO, to sea water makes both the entrance of carbonic acid and the increase in alkalinity more rapid than does the addition of NaHCO,. The potassium ion therefore affects the permeability of the protoplasm to the potassium ion or to other ions. These processes do not occur in dead plants.

Other anions studied, citrate, acetate, and chloride, do not produce so great an increase in the alkalinity of the CO2-free sap, but also show the greater influence of the K-ion over Na in producing this alkalinity.

Acknowledgments. The writer takes pleasure in acknowledging the courtesies afforded by the Miami Aquarium Association, where this work was done, and in expressing much gratitude to the authorities of the Carnegie Institution of Washington, D. C., who made arrangements for collecting the plants.

REFERENCES.

(1) Brooks, M. M.: Jour. Gen. Physiol., iv, 347. 1922. (2) Jacobs, M. H.: Amer. Jour. Physiol. liii, 457. 1920.

INCIDENCE OF VENEREAL DISEASES AMONG AMERICAN SEAMEN IN THE ORIENT.

By M. R. KING, Assistant Surgeon, United States Public Health Service.

Opportunity for the study of health conditions among American seamen in the Orient is especially favorable in the port of Manila, P. I., since this is the only station which furnishes both out-patient and hospital relief in this region. The out-patient relief station is maintained as an integral part of the quarantine office, whereas patients needing hospital care are sent to St. Paul's Hospital in Manila,

which is under contract to care for beneficiaries of the Public Health Service.

Of all disabilities encountered in the station of Manila, P. I., venereal diseases predominate. Approximately one patient out of every three who reports for treatment, is afflicted with venereal disease. The out-patient record cards on file show a total of 1,246 patients treated for various disabilities during the period October 23, 1920, to February 12, 1923, 36 per cent of whom were treated for venereal diseases. The in-patient cards show a total of 526 patients sent to the hospital during the above period, 30.4 per cent of whom were hospitalized for venereal diseases.

The number of days spent in the hospital for various disabilities was found to be greater for venereal diseases than for any other class of disability. All patients sent to the hospital during the period considered above consumed a total of 9,306 hospital days, 41.28 per cent of which were spent for venereal diseases. The accompanying table and graph, illustrating the relation of the above figures, are self-explanatory.

Percentage of total cases admitted to hospital and of hospital days on account of various classified disabilities.

One noteworthy factor is the greater percentage of chancroidal disease at this station as compared with this type of venereal disease reported in continental United States. Although the majority of cases of venereal ulcers were subjected to a Wassermann reaction, undoubtedly some errors in diagnosis have been made, owing to the early stage of most of the cases. However, even if considerable allowance is made for mistakes in diagnosis between syphilis and chancroid, the greater prevalence of the latter is marked. The annual report of the Surgeon General of the United States Public

1 Venereal diseases constitute one-third of all cases of disease among sailors in the port of Hamberg. Germany, according to the returns of the Hamburg port medical officer (PUBLIC HEAlth Reports, May 2, 1923, p. 1141).-Editor.

Health Service for the fiscal year 1922 shows that the reports of cases of venereal diseases received from the State boards of health totaled 333,718 for the year ended June 30, 1922, of which number 2.68 per cent were chancroid, 51.18 per cent syphilis, and 45.80 per cent gonorrhea. Out of the total of 606 venereal cases considered here, 30.37 per cent were chancroid, 12.38 per cent syphilis, and 57.27 per cent gonorrhea. A comparison of these figures shows 27.69 per hundred more cases of chancroid and 38.80 per hundred fewer cases of syphilis in this district.

One of the main causes of the increase in the number of venereal disease cases among American seamen is the unrestricted and marked prevalence of prostitution in many of the seaport cities of the Orient.

Graphic representation of percentage of total cases and hospital days due to various classified disabilities.

The majority of our patients have acquired their infection in Japanese and Chinese seaports, and by the time Manila is reached the disease has secured a firm foothold and is acute and virulent in nature, with frequent complications. By direct inquiry it was learned that solicitation is practiced on the streets in the cities of the Orient; also that it is not an unusual thing for a rickshaw man, on his own initiative, to carry a stranger to a house of ill repute when out sightseeing. Many of the seamen confessed to being intoxicated at time of infection. The prevalence of chancroidal disease may be associated with greater personal filthiness in oriental ports. Chancroid is more easily prevented by simple cleanliness than gonorrhea or syphilis. The fact that many of the cases run a very severe