attention being given to disinfecting the spaces between the floor boards, the wall paper should be washed or wiped in the same solutions, unless they are considered too valuable to spoil; clothing should be disinfected by steam or by boiling,-when this is done there is not much left for the sulphur fumigation, and it may be trusted to do it.

A paper by Esmarch* appeared in 1887, which might be paraphrased as "The Disinfection of Walls with Bread," and the author's suggestion for freeing walls of bacteria were so contrary to the reader's sense of the fitness of things that he had to recall himself to the fact that he had not opened a journal given to the travesty of one of the most sacred articles in the creed of the sanitarian. The walls of rooms, whether they are papered, painted or simply finished in plaster, no matter how smooth they appear to the eye, in reality they are not so, and in their niches and on their projecting ledges disease producing bacteria find ample lodgement.

That this is not mere assumption is shown by the experiments of Esmarch. Rubbing 25 square centimeters of the walls of different rooms with bits of sterilized sponge and afterwards making cultures from them, he obtained from the walls of a stable from 231 to over 6,000 bacteria, on the walls of the laboratory, from 2 to 112 according to location and character of surface; in a dwelling room from 2 to 153 bacteria. Some of the results obtained from these preliminary investigations of the germ contents of walls are interesting, particularly in one house in which a part of the paper hanging and painting was old and a part new. In this house, in the living room, on the old paper there were 14 bacteria, another place 12, and another 10; on the new paper, three months old, 5; in the corridor, old paper, 43; in the closet, old paper, 38, in another place, 31; in kitchen, kalsomined wall, 14, oil painted wall, 14; sleeping-room, oil painted, one month old, 1. In another house in which there had been no thorough cleaning of the walls for sixteen years he obtained distinctly higher numbers.

Investigating the condition of the walls after they had been disinfected by various processes, he came to the conclusion that the most efficient method of removing bacteria from them was by 'rubbing the walls with bread.

For a long while in Germany the cleansing of walls by rubbing with bread had been a process in favor with the public, as in this

*Zeitschrift für Hygiene II., 491.

way, whether papered or painted, they could be, without injury, freed from dirt and renovated in appearance.

Esmarch found that by rubbing down the walls with bread they were freed more completely from bacteria than after washing or spraying with 1:1.000 sublimate solution, or 5 per cent. carbolic solution. The superiority of this method of cleansing walls was so conclusively shown that the process has since been adopted in the official regulations of many cities.

The kind of bread and method of procedure recommended is as follows: Common rye bread, new and well baked through, is cut into pieces of a size convenient for the hand so that they may be grasped by the hard outer crust. With these pieces of bread, held so that the hand does not touch the wall, I could very conveniently with moderate pressure rub the walls. In most of the cases the walls were rubbed only once, and in doing so the surface of the bread was blackened very distinctly. The crumbs falling to the floor are to be carefully swept up and burned, not fed to animals.

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An interesting paper was contributed two years ago by Krupin*, a Russian surgeon in the Alexander Barracks-Hospital, St. Petersburg. From the experience in that hospital and from their studies of the current literature, the surgeons were inclined to divide infectious diseases, into two classes, a division of some importance in connection with the adoption of measures for the disinfection of rooms. In one class they placed those diseases whose infection is characterized by a tendency to adhere to surfaces upon which they have found a lodgement, as diphtheria, scarlet fever, croupous pneumonia, smallpox, erysipelas, and dysentery; in the other class, those diseases whose infection is possessed of but feeble powers of vitality, as relapsing fever, typhus fever, and measles.

Upon the opening of the Hospital the process of disinfecting with chlorine gas was adopted for rooms and wards which had contained infectious cases, and in connection with certain diseases this appeared to be sufficient; for example, after typhus fever, typhoid fever, and relapsing fever, scarlet fever, measles and small-pox.

The first doubt as to the efficacy of chlorine disinfection was raised after the disinfection of a barrack on account of diphtheria. In barrack No. 17, containing scarlet fever patients, one case was found to be complicated with diphtheria toward the end of the epidemic. In a short time afterward, several convalescents from scarlet fever in the same barrack were attacked with diphtheria. The barrack was therefore closed, and thoroughly disinfected with chlo

*Zeitschrift für Hygiene III., 219. 1888.

rine gas. After disinfection, this barrack was washed, ventilated, and for seven months it remained vacant. When it was again opened it was occupied for four months with measles patients, and during this time a few cases of measles were complicated with diphtheria, although none of these patients had bad this complication when received. Again the barrack was vacated, still more thoroughly disinfected with chlorine gas and again remained vacant, this time seven months. When it was again opened it was devoted to smallpox patients, and some of these patients had diphtheria as a complication. In addition to these, the barrack physician, two nurses and a waiter, in short, the whole personnel of attendants. Again the barrack was closed, and a third time disinfected with chlorine gas. When this barrack was again opened, it was used for typhoid fever patients, adults only being received, and no further cases of diphtheria occurred.

This experience led them to make an investigation as to the disinfecting power of chlorine gas for certain well-known pathogenic bacteria, particularly anthrax spores. The results of these experiments were not satisfactory, and finally led to the abandoning of chlorine in the disinfection of rooms.

From further laboratory experiments and from a long series of subsequent experiences in the disinfection of rooms, Krupin comes to the following conclusions:

1st. The disinfection of sick rooms is best done by washing or sprinkling with sublimate or carbolic acid solutions.

2d. The most efficient agent for disinfecting rooms is a solution of corrosive sublimate 1 :1,000 alone, or half and half with a solution of carbolic acid 5:100.

3d. As far as our experience yet shows, these methods of disinfection are entirely harmless for the subsequent inhabitants of the

rooms.

DISINFECTION OF EXCRETA.

A series of experiments was carried out by Dr. Foote in the laboratories of the Yale Medical School for the purpose of determining whether corrosive sublimate is a good disinfectant for feces, and if it is not, whether this is due to the formation of inert, insoluble compounds of mercury with the feces; 2d, to determine the relative value of certain other disinfectants used for this purpose. As a test mixture, normal feces were used, mixed with about two-thirds their bulk of decomposing urine.

The following standard solutions of the disinfectants to be tested were made up according to the following formulæ :

Corros. subl., two drachms; water, one gallon.

*Amer. Jour. of the Med. Sciences XCVIII., 329. 1889.

Chloride of lime, four ounces; water, one gallon.

Sulphate of iron, eighteen ounces; water, one gallon.

Corros. subl., two drachms; tartaric acid, ten drachms; water, one gallon.

Hydrochloric acid, one per cent. (ten drachm3 to one gallon). Corros. subl., two drachms; hydrochloric acid, ten drachms; water, one gallon.

Carbolic acid, five per cent. solution.

Corros. subl., two drachms; potass. permang., two drachms; water, one gallon.

These experiments furnished an excellent opportunity to observe the deodorant effects of the disinfectants tested. Sulphate of iron, which is often regarded as a good deodorant, developed an odor considerably more disagreeable than that of the mixture of feces with sterilized water. The odor did not seem to be lessened in any appreciable degree after seventy-two hours when the flask was emptied. The bichloride and the mixtures of the bichloride with hydrochloric acid, tartaric acid, and potassium permanganate are primarily good deodorants. Thus at the end of four hours there was no appreciable odor from mixtures containing these. After forty-eight hours, however, a very sickening odor was developed in all these mixtures. This was not of putrefactive origin, since the mixtures were frequently perfectly sterile. Chloride of lime rapidly destroyed all fecal odor, but replaced it by its own. Carbolic acid also destroyed all fecal odor after four hours.

The experiments showed that:

The bichloride with hydrochloric acid is by far the most efficient disinfectant. Next in order stands chloride of lime, it acts less efficiently, but more rapidly than the bichloride with hydrochloric acid.

The addition of tartaric acid to the bichloride solution somewhat increases its power, though not nearly so much as hydrochloric acid. The sulphate of iron shows itself totally inefficient, both as a disinfectant and deodorizer, and there is no rational basis for its use for these purposes. One per cent. solution of hydrochloric acid, and five per cent. solutions of carbolic acid, have little power as disinfectants.

The addition of potassium permanganate to the bichloride solution considerably increases its efficacy.

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simple bichloride solution has also shown itself unreliable. The chemical analyses of the filtrates has shown that considerable mercury exists in solution in them, and the bacteriological tests * have shown that this soluble form of mercury is a powerful germicide-even when diluted one-half, capable of destroying the bacillus typhosus after an exposure of six hours; consequently the inefficacy of the bichloride as a disinfectant does not seem to be due to the fact that it forms insoluble, inert compounds with organic matter, for the compounds are neither insoluble

nor inert, but rather due to the lack of power of penetrating organic matter. This being the case, it is doubtful if an increase, within certain limits, in the proportion of the bichloride to the feces, would increase its efficacy much.

Experiment VI. further shows that one pint of the best disinfectants (bichloride with hydrochloric acid, bichloride with potassium permanganate, and chloride of lime) is sufficient to sterilize a semisolid dejection consisting of 100 c. c., after four hours' exposure, but that it is insufficient to sterilize, after four hours' exposure, one of 250 c. c. in a small proportion of cases. Therefore, one pint of these disinfectants should be used to every 100 c. c. of a semi-solid dejection.

These experiments were all performed with normal feces. The probability is very slight that these same disinfectants which are efficient in sterilizing normal feces would prove inefficient in cases where pathogenic germs exist, since the spores of the hay bacillus which exist in normal feces are certainly as resistant to the action of germicides as the most resistant pathogenic germs, and far more resistant than the pathogenic germs most common in feces, such as the bacillus typhosus and the comma bacillus.

Conclusions.-The best disinfectants to use are the bichloride with hydrochloric acid, the bichloride with potassium permanganate, and the chloride of lime.

Five per cent. solutions of carbolic acid and two-tenths per cent. solutions of the bichloride are unreliable even when used in the proportion of one pint to every 100 c. c. of dejection.

Emphasis needs to be laid on the necessity of thorough disintegration of the fecal matter by stirring with the disinfectant, and on the necessity of allowing the mixture to stand four hours, at least, before emptying.

For continued use the bichloride solutions would injure lead pipe, while if used for a few days only, probably no injury would result. For long continued use, where the dejections are thrown into a water-closet, chloride of lime is undoubtedly the most available disinfectant.

Solutions of chloride of lime should be kept tightly corked and should not be used after they are one week old.

At the request of the city government of Buda-Pesth, Dr. Gerlóczy in the Hygienic Institute in that city made an extensive series of investigations for the purpose of determining the most suitable agents to be used for the disinfection of privy vaults, sewage, the mud and slime of streets, dry garbage, and fresh excreta, particularly from diarrheal and typhoid fever patients.

The disinfectants tested were corrosive sublimate, sulphate of copper, sulphate of zinc, sulphate of iron, pure carbolic acid, crude carbolic acid, said to be of some 25 to 30 per cent., carbolate of lime, creolin, crude sulphuric acid, milk of lime 20 per cent., boil