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Disinfection and Disinfectants 


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Disinfection and Disinfectants 














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No recent attempt has been made to summarise and review 
the very voluminous literature on the subject of Disinfection 
which is scattered through our own and foreign Scientific and 
Medical publications, and, notwithstanding the rapid develop- 
ment of Sanitary Science in this country, there does not exist 
at the present time, in the English language, any book which 
deals exclusively with the composition of Disinfectants. 

The present volume may, therefore, supply a want which 
has been felt, not only by the chemist and bacteriologist, but 
also by all those who, like medical officers of health and 
borough surveyors, are concerned with the practical work of 

Owing to the attention which has been given to bacterio- 
logical science during the last ten years, the methods of 
Disinfection are now being reviewed under the more exact 
conditions which this knowledge has rendered possible. The 
time is not far distant when the importance of the thorough 
disinfection of all suspected areas will be fully realised by 
local authorities, and when all such work will be entrusted 
to specially qualified men, instead of being regarded as a 
subsidiary duty of the inspector of nuisances. The Sanitary 
Institute of Great Britain has for some years insisted that 
the duties of a Sanitary Inspector are such as to necessitate 
a considerable amount of practical experience and scientific 
knowledge. If, as at present, the proper carrying out of the 
work of Disinfection forms part of their duties, the responsi- 
bility of such men is considerably augmented. 

It has become customary in many districts for the public 



Analyst to advise the sanitary committee on the chemical 
composition of new disinfectants, and, although this practice 
should without doubt he generally adopted, it must not be 
forgotten that a continuous control over the strength and 
bactericidal activity must be maintained after any particular 
disinfectant has been finally selected. 

The laudable attempts of the medical oflScers of health in 
some districts to stamp out sporadic outbreaks of infectious 
disease so soon as they are notified to them, are to a con- 
siderable extent nullified by the slackness which obtains in , 
neighbouring areas, where a lavish display of untested disin- 
fectant powders in the street gullies, or the use of a strongly 
smelling or high-coloured fluid of unknown composition, is 
relied upon to satisfy the public demand for hygienic condi- 
tions of life. 

The following pages may help in discriminating between 
useful disinfection and the futile attempts which give a false 
sense of security to many localities in the time of danger. 

I am indebted to Mr. H. B. Ransom, A,M.Inst.C.E., for the 
principal portion of the chapter on Disinfection by Heat, 
and his practical acquaintance with the engineering details 
of difl'erent forms of disinfecting plant has enabled me to 
give this section much greater value than it otherwise 
would have possessed. For several suggestions and the account 
of methods for the bacteriological examination of disinfectants, 
I have to thank my former colleague. Dr. C. Slater, of 
St. George's Hospital; and my thanks are also due to 
Dr. Louis Parkes, the Medical Officer of Health for Chelsea, 
for advice and for his kindness in reading the proof sheets. 

Westminster, June, 1895. 


Chapter I.— Introductory. 

Definition of terms, 
Primitive modes of disinfecting, . 
Disinfection in the Middle Ages, . 
Bacteriology, . . . . 



Methods of dealing with bacteria, 

1. By exclusion, 

2. ,, removal, 

3. ,, destruction, . 




Chapter II.— Mechanical Disinfection. 

lusufficiency of deodorisation. 


Ashes and cinders, . 






Mechanical purification 

of gases 

Sand filtration, . 


and liquids, . 


Stone filters, . 


Carbon, . 


Clark's softening process. 




Other ,, processes, 






Infusorial earth, 


Chapter III.— Disinfection by Heat. 

Heat as a disinfectant, . . 19 

Conditions required in a disinfector, 23 
Modes of dealing with disinfection, 27 
Time and steam conditions re- 
quired for disinfection, . . 29 
Experiments on the penetrating 

power of steam, ... 33 
English apparatus— Washington- 
Lyon's patent, ... 34 
Typ«s of disinfectors used on the 

Continent, .... 42 

1. Austria — Thursfield's appar- 

atus, .... 

2. France— The Equifex stove, 

3. Denmark — Reek's apparatus, 

4. Germany — Schimmel's and 

Budenberg's ap])aratus. 
United States, 
Public installations, . 

Plan of a disinfector house. 
United States, 




Chapter IV.— Chemical Disinfectants —The Non-MetalliC: 
Elements and their Derivatives. 

Halogens and their compounds. 


Periodates, .... 




Organic compounds containing 

Chloride of lime and hypo 

the halogens. 


chlorites, . 


Chloroform, .... 


The "Hermite" process. 


Bromoform, .... 




Iodoform, .... 


Hydrochloric acid, . 


Ethyl iodide, . . . . 


Chlorides, ... 


Organic compounds containing 





Iodine, .... 


Fluorine, .... 


Iodine trichloride, . 







Chapter V.— The Non-Metallic Elements and their 
Derivatives ^(cow^mMeti). 



Peroxide of hydrogen, 

Nitric acid and oxides of nitrogen, 

Nitric acid, 

Nitrogen trioxide, 
; Nitrites, . 

Nitric peroxide, 

Nitrous ether. 
Sulphur and its compounds, 
> Sulphuretted hjdrogen, . 

Sulphur dioxide. 



Sulphur fumigation, 






Sulphites in food, . 
Sulphuric acid, 

Bisulphide of carbon. 
Boric acid and borates. 


Boric acid, 


Borates, .... 


Borax, .... 


Ammonium borate, 


Potassic borotartrate, 


Benzoboracic acid, . 


Tests for borates. 


Influence of gases on putrefaction, 104 
Carbon dioxide, . . . 104 

Chapter VL— Metallic Salts. 

Salts of the alkalies and alkaline 

Zinc sulphocarbolate, 


earths, .... 

. 106 

,, salicylate. 


Sulphate of lime, 

. 107 



Carbonate of lime, . 

. 107 

Cuprous chloride, 




Cupric ,, 


Slaked lime, 


,, sulphate, 


Sodium carbonate, . 

. 108 





Iron, . 


Ammonium carbonate. 


Metallic iron, . 




Ferrous sulphate. 


Oxide of zinc, . 


Ferric sulphate, 


Chloride of zinc, 


,, chloride, 


Zinc nitrate, . 




,, sulphate, . 


Peroxide of manganese, 


„ acetate, . 


Manganates and permanganate 

s, 123 

,, sulphite, . 


Potassium permanganate. 


:Chapter VII. 

—Metallic Salts (continued). 

Aluminium salts. 


Basic acetate of lead, 


Use in sewage precipitation. 


Mercury compounds, . 


Aluminium chloride. 


Mercuric and mercurous nitrate 

s, 135 

,, acetate, 


,, chloride, . 


„ sulphites, 


, albuminate, 




, iodide. 


Chromic acid, . 


, cyanide, . 


Potassium bichromate. 


, zinc cyanide. 


Arsenic, . . -. . 


, chloroamide. 


Arsenious acid. 


, organic compounds, . 


Potassium arsenite, ; 


Compounds of various metals. 


Sodium arsenite, 


Tin — stannous chloride, . 


Acetoarsenite of copper, . 


Bismuth subgallate (dermatol), 


Arsenious sulphide. 


Silver nitrate, . . . . 


Arsenic acid, .... 


Osmic acid, . . . . 


Lead, . . . ; , 


General remarks on disinfectants. 


Nitrate of lead, 




Chapter VIII 

.—Organic Substances. 



Tar and its products, . 


Pixol, .... 


I. Hydrocarbons, . 




Naphthalene, . 






Jeyes' disinfectant, . 




Creolin, .... 


II. Phenols, .... 


Essets' fluid, . 


III. Basic substances. 


Saprol, .... 


Phenol or carbolic acid, 








Carbolic powders, . 




Carbolised solution, oil, and gauze 

, 155 

Pyrocatechol, . 


Carbolic wool, .... 




Danger of phenol in surgery, . 


Wood- tar derivatives, • 


Carbolic soaps. 


Pyroligneous acid, . 


Various preparations. 


Stockholm tar. 


Halogen derivatives of phenol, . 


Retinol, .... 


Parachlorophenol, . 


Resol, .... 




Wood creosote, 


lodophenols, .... 


Guaiacol, .... 


Sulphuric derivatives, 


,, carboxylate, 


Sulphocarbolates, . 


Creosol, .... 


Sozo-iodol, .... 


Little's soluble phenyle, . 


Aseptol, ..... 


Naphthalene derivatives, . 




Naphthalene, . 


Benzene sulphonic acid, . 


Naphthalene-sulphonic acid. 


Phenyl-substituted fatty acids, 




Cresol and the higher phenols, . 


Betol, . 


Creosote oils, .... 






Alumnol, .... 


Bacillite, ..... 






Oxynaphthoic acid, . 


Chapter IX.— Organic Substances {continued). 

















Nitro-cresol, . 


Pyrrol, .... 



, 182 






. 188 



Pyridine group, . . -. 

. 189 



Conine, . •. . . 










Methylamine, . 












Propylamine, . 


Qninoline derivatives. 






Aminol, .... 


Diaphtherin, . 


Aniline, .... 


Oxyquinoline, . 


Acetanilides, . 




Aniline dyes as antiseptics. 


Thalline, . . . . 


Methyl violets. 




Pyoctanin, . . . . 


Antiseptol, . . . . 




Chapter X.— Organic Substances (continued). 



Benzoic acid group, 

. 195 

Styrone, .... 

. 205 

Benzoic acid, . 

. 195 

Sodium dithiosalicylate, . 
Thymol, camphors, and essentia 

. 205 


. 197 


Benzoic aldehyde. 

. 197 


. 206 

Sulphobenzoic acid, 

. 197 

Turpentines, . 

. 207 


. 197 


. 208 


. 198 




. 198 

Aristol, .... 


Salicylic acid, 

Oil of wintergreen, 

. 198 


. 209 

. 199 

Oil of cloves, . 

. 209 

Salol, . 

. 199 

Oils of caraway, cinnamon, &c 

., 210 


. 199 

Essence of hops. 

. 210 


. 200 


. 210 

Salicylic acid as an a 

mtiseptic, 200 




. 202 



Salicylic acid as a pi 

•eservative, 202 

Eucalypto-resorcin, . 


Antiseptic tablets, 

. 204 

Myrtol, .... 

. 212 

Salicylated gauze, 

. 204 

Terpin hydrate. 


Anisic acid, 

. 204 


. 212 

Cinnamic acid. 


Borneol, .... 

. 212 


. 205 


. 213 

Phenol-propionic aci 

d, . . 205 

Oxidising power of essential oils, 213 

Gallic acid. 

. 205 

Sanitas preparations. 

. 215 

Tannin, . 

. 205 


. 218 

Chapter XI.— Compounds Related to the Alcohols. 

Methyl alcohol, . 

. 219 

Pyroligneous acid. 

. 226 

,, chloride. 

. 219 

Glycerine, .... 

. 226 

Formic aldehyde. 

. 219 

Oleic acid, .... 

. 227 

Other aldehydes, 

. 223 

Petroleum and paraffins, 

. 227 


. 223 

Vegetable acids, . 

. 227 

Formic acid. 

. 225 

Oxalic acid, 

. 228 

Acetic acid, 

. 225 


hapter XII.— Pr 

•aetieal Methods. 

Sanitary administratio 

n, . . 228 


. 238 

Sewers and drains. 

. 229 

Pail system. 

. 239 

Ashpits and dust-holes 

. 231 

Privies, .... 

. 239 


. 231 

Cesspools, .... 

. 240 

Hygienic wall-papers, 

. 231 

Streets, .... 

. 241 

Furniture and woodwt 

)rk, . . 232 

Wood paving. 

. 242 

Sinks, . 

. 232 


. 242 

Sick rooms. 

. 232 

Stables, pig-styes, and cowsheds 

, 24S 


. 232 


. 243 

Clothing, . 

. 232 


. 243 

Excreta, . 

. 233 

Pigeon and fowl houses, &c. , 

. 243 

Light and air, . 

. 233 


. 244 


. 234 

Vehicles, .... 

. 244 

a. Phenol, . 

. 234 

Skins, furs, wool, hair. 


b. Sulphurous aci( 

i, . .234 


. 244 

c. Chlorine, . 

. 234 

Disinfection of air. 

. 245 

d. Non-volatile di 

sinfectants, 235 

Apparatus for sewer gas, 

. 246 

Clothes, bedding, &< 

5., . . 236 


. 246 

Hos])itals, . 

. 236 

Water, .... 

. 247 

Cisterns, , . . 

. 237 

Preservation of timber. 

. 250 


. 237 



Chapter XIII.— Personal and Internal Disinfection- 
Food Preservation. 


Personal disinfection, . . . 252 
Disinfection of cavities of the 

body, .... 254 

a. Washing oat, . . . 254 

b. Spraying, . . . 254 

c. Gargles, .... 255 

d. Injectionsof gases or vapours, 255 

e. Inhalations, . . . 256 
Antiseptic dressings, . . 256 

Gauzes and wools, . . 256 

Antiseptic hypodermic injections, 257 

Antiseptic soaps, . . . 257 

Mouth washes and tooth powders, 258 

Ointments, .... 259 

Respirators, .... 259 

Internal disinfection, . . 259 

„ antisepsis, . . . 260 

Vaccination, .... 262 

Preservation of food, . , . 262 

Causes of change in food, . 262 

1. By oxidation, . . . 262 


2. By reduction, . . . '262 

3. By metallic contamination, 263 

4. By organisms, . . . 264 

Drying, 265 

Smoking, 265 

Cold 266 

Preservation by chemicals, . 287 

„ ,, heat, . . 268 

1. The chloride of calciam 

process, . . . 269 

2. The Aberdeen process, . 269 

3. Jones's vacuum process, . 269 

4. Salzer's Baltimore process, 269 

5. Budenberg's flesh steriliser, 271 

6. G. Hartmann's process, . 272 

7. Formaldehyde „ . 272 

Milk, 272 

Condensed milk, . . . 273 

Butter, 274 

Cheese, 275 

Wheat— Bread, . . 275 

Cliapter XIV.— Legal Statutes and Regulations. 

Duties of a medical officer of 
health, ..... 

Sanitary inspectors. 

Public Health Act, 1875, . 
Hospitals for infectious diseases. 
Prevention of epidemic diseases, 
Mortuaries, .... 
Port sanitary authorities. 

General order L. G. Board on 
cholera, .... 
Regulations as to detention, 

Dairies, Cowsheds, and Milkshops 
Order, 1885 

Regulation of bakehouses, . 

Housing of the Working Classes 
Act, 1890, .... 

Public Health (Water) Act, 1878, 

Vaccination Acts, 1867, 1871, 1874, 

Burial regulations. 

Merchant Shipping Acts, 1854 
to 1876, 

Canal Boats Acts, 1S77, 1884, . 

Infectious Diseases (Notification) 
Act, 1889, .... 

Infectious Diseases (Prevention) 
Act, 1890, .... 

Public Health Amendment Act, 

Public Health (London) Act, 1891, 

Memorandum on hospital accom- 
modation, .... 

Memorandum on ambulances. 

Rules for hospitals for infectious 





Circular of the medical officer 


(L. G. Boardi, .... 



Suggestions of the Society of 


Medical Officers of Health, 



Model bye-laws as to cleansing, 


&c. , 

Model bye-laws as to nuisances 



and animals, .... 



Model bye-laws as to buildings, . 


Metropolitan Asylums' Board, . 



Legislation as to vagrants, . 



Systems in other countries, 





Germany (Berlin), . 



(Leipzig), . 






Denmark, .... 





Special rules for disinfection. 



1. Discharges, .... 


2. Privies 



3. Clothing, .... 


4. Furniture, .... 



5. Rooms, &c.. 


6. Persons attending patients, 



7. Drinks 



American Public Health Associa- 




Quarantine, .... 







Chapter XV.— Methods of Analysis. 

A. Bacteriological methods, 
Determination of the antiseptic 
value, .... 
I. Examination of soluble 
antiseptics in solution, 
[I. Examination of the vapours 
of volatile fluids, 
III. Examination of gaseous 
Determination of the germicidal 


Principle of the methods, 
Relative value of tests, . 

(a) Sternberg's method, 

(b) Drop „ 

(c) Thread ,, 





Examination of gases and 

vapours, . 



Fischer and Proskauer's 

method, . 




B. Chemical methods — 

Chloride of lime. 



Sulphites and sulphurous acid, 


Peroxide of hydrogen, 



Boric acid, .... 








Tar preparations, 



Carbolic powders, . 



Salicylic acid and other preser 


vatives in foods, . 



Medicated wools. 


Bibliography, 317 

Index 323. 



Definition of Terms — Primitive Methods of Disinfecting — Bacteriology — The 
Methods of dealing with Bacteria by Exclusion, Bemoval, and Destruction. 

Definition of Tenns. — The words *' disinfectant " and " disinfection " 
have in recent years been used in such a variety of ways, and with 
such wide application, that much confusion has arisen as to the 
exact meaning of these terms. 

Before the germ theory was universally accepted, the term "disin- 
fection" was used to include the destruction of infectious matter and 
the removal of any noxious odours to which such matter gives rise. 
It was applied to the action of any substance which served as a mask 
for noxious odours, and many substances which have a powerful 
odour have probably become popular, as disinfectants, solely from this 
cause. After the germ theory had offered a plausible explanation of 
the origin of disease, it became possible to define a disinfectant as a 
germicide. Disinfection then ceased to mean simply "purification," 
but acquired the special meaning of " sterilisation." A true disin- 
fectant, therefore, must not only mask the smell, but must destroy 
or kill the germs which give rise to it. Many poisons have the 
property of killing germs as well as acting upon the higher forms of 
life, and could, therefore, be used as universal destroyers of life ; but, 
in many cases when disinfection is resorted to, it is desirable to 
use some agent which will discriminate between useful life and in- 
fectious matter. Such an ideal disinfectant should, therefore, be a 
substance that will kill those germs which act injuriously on the 
higher forms of life, without having any marked action upon such 
higher forms. A disinfectant must likewise be efficient in destroying 
the spores of pathogenic organisms, which, as a rule, are more 
resistant than the germs which form them. From this de6nition it 



will be seen that a disinfectant does much more than prevent decom- 
position, and does more than remove the noxious smells which often 
emanate from putrefying matter. A disinfectant really goes to the 
source of the trouble, and, by killing the organism, prevents the 
spread of epidemic disease. An antiseptic, on the other hand, 
prevents animal or vegetable substances from undergoing decom- 
position, and a body is said to be aseptic when it is in a condition 
of sterility. A substance which has the property of absorbing the 
unpleasant odours which are emitted from matter undergoing decay 
is called a deodorant, and such substances must be carefully distin- 
guished from true disinfectants. Most disinfectants are deodorants ; 
but a deodorant, unless of a permanent character, is not an antiseptic. 
It is true that in most cases a noxious smell accompanies decay, and, 
therefore, that any substance which permanently removes the smell 
must necessarily cause the cessation of the decay ; but in other cases 
in which there is no appreciable odour, a deodorant would not be 
required. Charcoal is an example of a body that will absorb any 
' unpleasant smell which may arise from organic matter, but which 
does not kill the germ producing the decay. Although commonly 
called a disinfectant, it should be more properly classified among the 

Primitive Methods of Disinfecting. — Man has an instinctive repugnance 
to all noxious odours, and from the earliest time has sought to mask 
their presence by the use of aromatic substances. The use of perfumes 
is probably a relic of the effort of primitive man to counteract this 
evil. Many religious ceremonies, such as the burning of incense, have 
also the same origin, and embalming, as practised by the Egyptians, 
is a good example of successful attempts to arrest putrefaction in very 
early ages. Sulphur has been employed from the earliest times, and 
Homer describes its use in religious ceremonies. In the time of 
Hippocrates, sulphur was regarded as an antidote against the plague. 
Ovid makes mention of the fact that sulphur was employed by the 
shepherds of his time for bleaching fleeces and for purifying their 
wool from contagious diseases. During the plague of Athens, Acron, 
according to Plutarch, stayed the spread of the epidemic by lighting 
fires in the middle of the public places and in the streets where deaths 
had occurred ; and the lighting of fires during times of plague has been 
customary until quite recent times. 

The Mosaic law, with all its minute instructions as to the purifica- 
tion of the people and their belongings, shows the same combination 
of religious ceremonial and sanitary precautions ; this law, undoubtedly, 
contributed to the permanency of the Jewish race during its early 
liistory. The Indian who, instead of embalming or burying his dead 


friend, hangs the body under a tree exposed to the air, makes use of 
the property of desiccation, which, as is well known, is very efficient in 
arresting decay, and is the basis of a modem patent for keeping yeast. 
Earth is a very powerful deodorant and will also act as an antiseptic ; 
the gases given off by decaying bodies are absorbed, and thus the 
burying of a body under proper conditions may be regarded as an 
efficient means of disinfection. The use of fire for cremating bodies 
undergoing decay or likely to cause a nuisance is, of course, an illustra- 
tion of the employment of heat for the destruction of micro-organisms. 

Disinfection in the Middle Ages. — During the long period of the 
Middle Ages, the alchemists did little to advance our knowledge of 
this subject ; they collected a few facts, and described, with more or 
less accuracy, the properties of some of the more important chemical 
compounds ; but one may search in vain for a correct account of any 
example of preventive medicine. Notwithstanding the ravages of the 
cholera, the plague, and other epidemics, as well as the frequency of 
leprosy, the idea of contagion was only imperfectly understood, and 
the common people were far less cleanly in their habits than the Jews, 
for example, or heathen nations who, as we have already mentioned, 
mingled primitive sanitary precautions with their religious services. 
Perhaps one of the earliest papers of any importance which we have is 
a Memoire sur les substances septiques et aniiseptiques, written by Pringle 
in the middle of the eighteenth century. In this Memoire some forty- 
eight experiments are described, in which the author took pieces of 
fresh meat and placed them in contact with various amounts of sub- 
stances which be believed to have an antiseptic action. Amongst the 
substances tried we find common salt, sal ammoniac, acetates of 
ammonia and potash, nitre, borax, alum, camphor, aloes, and succinic 
acid. These experiments, which were conducted in a very systematic 
manner, are even now not without some value. By taking as a 
standard the antiseptic action of 60 grains of salt on 2 grains of 
meat in 2 ounces of water, he was able to show that the other bodies 
enumerated above had a greater antiseptic power than this standard, 
and thus succeeded in arriving at their relative antiseptic value. 

Bacteriology. — Even the pioneers of modern chemistry at the begin- 
ning of the present century, did little towards promoting our knowledge 
of disinfectants, and it was not until the biologist showed that decay 
was due to the action of living organisms which float in the air, that 
fresh attention was directed to the subject, Francesco Redi, by pro- 
tecting meat from flies with wire gauze, showed that the maggots 
which infest decaying flesh were produced from the eggs of the flies. 
Subsequently the formation of moulds on the surface of jams, or other 
organic substances, was similarly shown to be determined by micro- 


organisms floating in the air. It was further noticed that infectious 
diseases spread more rapidly in damp warm weather when there is 
very little wind, and that filtration of the air through cotton wool was 
effectual, not only in removing the dust, but also in preventing the 
ingress of micro-organisms. 

The gradual accumulation of such facts as these by the biologists led 
the chemists to realise that the removal of the odour was not, after 
all, the only work required to be done, and the use of fumigations 
with nitrous acid, hydrochloric acid, and chlorine and other j)ungent 
bodies, which had been recommended, fell gradually into disfavour. 

Pasteur's work, together with the general development of the 
modern science of bacteriology, has given to chemists a means of 
ascertaining the relative value of the various chemical substances dis- 
covered from time to time. It was to Pasteur's careful investigations 
that the close analogy which exists between fermentation and putre- 
faction was established. Pasteur himself defined putrefaction as 
" fermentation without oxygen," and showed that all decay was due 
to the action of organisms, the Bacterium termo being the common 
organism which begins eremacausis. 

Owing to the slight knowledge which we possess as yet of the 
nature of the pabulum in which these bacteria of decay live, the 
investigation of the way in which they act is a matter of great 
difficulty. In recent years, however, the life -history of known 
organisms has been carefully studied, and the chemical changes which 
are produced when they live in media of known compositions have 
been followed. Thus organisms have been allowed to grow in solu- 
tions of calcium formate and calcium acetate, both of which substances 
have a definite chemical constitution. The bacteria decompose these 
salts, evolving carbonic acid gas, mixed with hydrogen in the former 
solution, and carbonic acid, mixed with marsh gas in the latter. 
Lactic acid and its salts, butyric acid and its compounds, as well as 
other chemical substances of known constitution, have also in recent 
years been examined bacteriologically. From studies such as these 
it seems to be clearly established that, just in the same way as the 
yeast when it converts sugar into alcohol is killed by the alcohol it- 
produces, so these other micro-organisms secrete chemical compounds 
which are inimical to their own life. In the decomposition of animal 
matter containing nitrogen, compounds which are soluble in weak 
alkaline solutions, and known as alkali albumens, are first ])roduced, 
and these subsequently change into albumoses and peptones, to be 
again broken down into tyrosine, indol, and other compounds. These 
latter have strong antiseptic properties, and illustrate the fact already 
alluded to — viz., that the products of decomposition are iu the 


majority of cases themselves inimical to the bacteria which give rise 
to them. 

The Methods of dealing with Bacteria.— The ideal of disinfection 
is to stamp out the pathogenic bacteria, just as weeds are extirpated 
from a garden. This can never be done until their hotbeds, the filthy 
slums of cities and the neglected country villages, are cleansed and 
supplied with plenty of good water, and, in the cities, with air and, 
above all, light. Every dirty court or alley is an admirable culture- 
medium in which disease organisms may multiply ; these issuing in 
a variety of ways, as by clothes, food, and even sometimes by the 
atmosphere, may unexpectedly decimate the so-called better neighbour- 
hoods. There is no reason why infectious disease of all kinds should 
not be entirely abolished ; but it can only be done when the entire 
population is supplied with knowledge, and placed under conditions 
in which health is possible. At present it is indispensable that 
measures of precaution should be taken continually and habitually to 
prevent any outbreak rather than, as too often is the case, only 
spasmodically when a plague like cholera threatens. The success of 
improved sanitation in rendering obsolete in modern Europe such 
plagues as carried off millions at intervals in the Middle Ages, shows 
that the abolition of infectious disease is possible, but we have 
still among us " that sad disgrace, our customary (and preventable) 
autumnal epidemic of scarlatina." This would certainly yield to a 
vigorous and systematic insistance upon isolation and application of 
disinfectants. With reference to the first precaution, more and better 
accommodation will have to be provided. As to the second, one great 
reason of the want of progress has been the fact, that many of the 
modes pf disinfection, even those prescribed by high authorities, are 
absolutely inefficient and useless. We must get rid, to begin with, of 
the idea that the creation of a rival smell is any criterion of safety ; 
we must cease to be misled by laudatory advertisements, and anti- 
quated opinions founded on inaccurate experiments before bacteriology 
became a science, and we must not grudge the expense of a sufficient 
quantity and a proper application of the disinfectants that have been 
proved scientifically to really effect their purpose. The problem then 
resolves itself into a struggle for existence between man and inimical 
micro-organisms, which are known to have great vitality, powers of 
endurance, and facilities for penetration, accompanied by a stupendous 
fecundity. The means at present at our disposal for dealing with this 
problem can be classed under three heads : — 

1. Exclnsion. — The rough methods of quarantine and sanitary 
cordons have not proved a success, since the ways of ingress are so 
many and wide, and the intolerable oppressiveness of these regulations 


leads certainly to their frequent evasion. The English methods of 
inspection, and temporary closure of certain routes, have proved much 
more effectual. The last, or personal, line of defence lies in the care 
and precautions taken by the individual. Most of these are indicated 
in Chap. XIII., "On Personal and Internal Disinfection." Cleanliness, 
fresh air, light, and good water are the chief 

In recent years it has also been shown that many, if not all, zymotic 
diseases may be excluded from the ])erson by the introduction of 
.special toxines into the individual, a process which renders him 
immune from the attacks of the organisms that produce the disease. 
These toxines are produced by the pathogenic organisms themselves, 
and, as already mentioned, are usually inimical to the growth of the 
organism, and may be regarded as their natural disinfectants. In 
view of these facts, Pasteur and his successors have cultivated the 
pathogenic organisms in broth and other media, and after sterilisation 
have injected the liqiiid products as prophylactics against various 
diseases. The virus can also be attenuated by passing it through 
different animals, or by special methods of taming, until, whilst still 
producing the toxines, it can be introduced into man without pro- 
ducing any dangerous symptoms, and thus can render him immune 
from fresh attacks, or place him in a position to develop the natural 
disinfectant sufficiently rapidly to kill off the pathogenic organisms, 
even after they have gained access to the blood. Dr. Roux, for 
example, at the Vienna Congress in 1894, reported a large number of 
cures of diphtheria by injecting a quantity of serum from the veins of 
a horse previously inoculated with Lo^ffler's diphtheria bacillus. Under 
the name of antitoxine, this diphtheria antidote is now a commercial 
article, and may be regarded as a special disinfectant for dealing with 
the organisms of this disease. 

2. Removal. — Under this heading may be included the natural pro- 
cesses which obtain in a healthy individual, and artificial methods for 
improving his environment. It is now well established that the blood 
by its white corpuscles, as "phagocytes," or by its enzymes, has the 
power of assimilating and destroying bacteria and spores that find 
their way into it. If vigorous health be maintained, experience proves 
that a human being or animal may enjoy immunity for a time, even 
when in an infectious area. The limit to this protection may be reached 
when the micro-organisms overcome the phagocytes or other defensive 
substances in the blood. Many natural processes, external to the indi- 
vidual, such as the self-purification of rivers, aid the higher organisms 
in this combat. Man, by artificial methods of subsidence, mechanical 
precipitation by inert matters, filtration, and chemical precipitation, 
supplements these efforts of nature to purify the water supplies. 


3. Destruction. — This is the office of real disinfectants, of which the 
physical agent heat is the most important. Next come the multitude 
of chemical disinfectants, many of which have been highly vaunted, 
but few of which are of actual value. A knowledge of the chemical 
constitution and relative position of these compounds throws con- 
siderable light on their mode of action ; and recent progress in 
synthetical organic chemistry has been of great aid in furnishing 
compounds of known purity and constitution, which have, at the hands 
of the bacteriologist, been shown to possess antiseptic and disinfectant 
properties of ascertained value. The number of these compounds is 
constantly on the increase, but at present it is difficult to predict, 
except in some few special cases, in what direction the constitution of 
a compound influences its bactericidal behaviour. It seems probable, 
however, that the several pathogenic organisms will be best annihilated 
by specific chemical compounds, so that, for personal disinfection at 
any rate, some of the newer compounds may eventually be proved to 
be definite specifics. 


Insufficiency of Deodorisation — Physical Means — Light capable of killing Bacteria 
— Sunlight and ordinary Daylight— Conclusions — Inert Substances : Carbon 
— Animal Charcoal — Vegetable Charcoal — Disinfection Gratings — Use in 
Closets — Peat Charcoal — Coke — Soot — Coal - dust — Peat — Sawdust — Clay — 
Dried Earth — Spongy Iron — Infusorial Earth or Kieselguhr — Ashes and 
Cinders — Gypsum — Sand Filtration : Conditions of its Efficiency— Chamber- 
land and Berkefeld Filters — Stone Filters — Purification of River Water : 
Clark's Method — Gaillet and Huet's Process — Natural Purification — Desicca- 
tion : Resistance of Microbes to Drying. 

Insufficiency of Deodorisation. — The simple removal of smell, or even 
the act of disguising it by a chemical of more powerful odour, is 
frequently looked upon as disinfection. Yet it is obvious that the 
removal of the injurious products of putrefaction, although it may be 
of temporary benefit, will not prevent the organisms from reproducing 
a further quantity. There are also a number of micro-organisms 
known, in whose growth there is never any ill smell evolved, and no 
ammonia or sulphuretted hydrogen detected ; but which, at the same 
time, form ptomaines, and are in other ways dangerous to health. 
Some of these, as pointed out by Klein, may evolve an aromatic smell 
and thus be tolerated. 


Light as a Disinfectant. — In those cases in which it is advisable that 
large volumes and surfaces should' be sterilised, it is not usuallj 
practicable to kill all the bacteria by chemical agents ; therefore 
recourse must be had to their removal by physical means. 


The action of light is one of the most important of these physical 
agencies for diminishing the number of microbes. 

Downes and Blunt* first demonstrated the antagonistic action of 
light towards bacteria. Test tubes containing sterilised Pasteur 
solutions were exposed to intermittent sunlight and diffused daylight 
for periods varying from days to months, having been previously 
infected by minute quantities of liquids containing bacteria, or else 
exposed for a time to ordinary air. A similar set of tubes were 
covered completely with tin-foil to exclude light, other conditions 
being the same. They found that direct sunlight in some cases 
entirely prevented the development of the organisms, in others only 
retarded it, and that even diffused daylight had a distinctly deterrent) 
effect. The blue and violet rays of the spectrum were much more 
active than the red and. orange. They further showed that the 
influence on spores was not exerted in a vacuum, that the nutritive 
value of the culture liquids was not afiected, and that the bacteria 
were much more resistant when immersed in water than when sur- 
rounded by any other medium. From these facts they attributed the 
destructive effect of light to the promotion of oxidation by the influence 
of the sun's rays — i.e., to the so-called actinism of light. (See Chapter 
xiii. as to the influence of light on the rancidity of butter.) 

A number of other investigators continued the research with pure 
cultivations of pathogenic bacteria, and particularly on the production 
of colours by the pigment-producing bacteria. It was noticed that the 
sun's rays appeared to favour the development of several kinds of yeast 
and moulds, and that the action of light was increased by the presence 
of air.f Pansini % found that the destruction was rapid during the 
first period of exposure, 360 colonies of B. anthracis being reduced in 
half an hour to 4, but that the further operation proceeded much 
more slowly. The spores of anthrax in a dry state were more 
resistant to light than when moist ; in the latter case an exposure of 
from thirty minutes to two hours was sufficient to destroy them, 

♦ Proc. Roy. Soc, Dec. 6, 1877. 

+ Arloing and Gaillard, Influence de la Lumiere sur lea Micro-org., Lyon, 1888 j 
Uffebnann, Hyg. Bedeiit. des Sonnenlichtes, 1889. 
X Rivista d'Igiene, 1889. 


Koch says that sunlight, or even ordinary daylight, will kill tubercle 
bacilli in from a few minutes to five or seven days, according to the 
thickness of the sti-atum.* Janowski has also prove<l that four to ten 
hours' sunlight destroyed typhoid bacilli. After passing through a 
solution of potassium bichromate, so as to cut off the blue and violet 
portions of the spectrum, the rays had no effect, t He showed also 
that the effect of the light was not due to increase of temperature. 
Geister demonstrated that an electric light of 1,000 candle j)Ower at 
1 metre distance was less effective than direct sunlight.:}: Marshal) 
Ward§ showed that the dried spores of anthrax were acted on by 
light in the absence of food materials, and that the light did not 
appreciably diminish the nutritive value of the agar-agar medium. 
Khmeleosky finds that both solar and electric light inhibit the growth 
of Staphylococcvs jyyogenes aureus, Bacillus pyocyane^is, Streptococcus 
erisiptelas, and .S'. jyyogenes. Sunlight destroys their vitality in about 
six hours, and exposure to sunlight seems to mitigate their virulence 
when it does not destroy them. It also makes the media less f ivour- 
able to their growth. || Percy Frankland and other investigators 
have examined the action of light on the organisms in the Thame* 
and other waters.U Buchner has also shown that in water typhoid 
and other cultures are destroyed by exposure to bright sunlight for 
three hours. By immersing cultures to* different depths in the 
Sternberger Lake at Munich he has further demonstrated that the 
;t(ericidal action does not extend to a greater depth than three yards, 
an3 that hence in the self-purification of rivers the action from this> 
cause is chiefly superficial. The conclusions of the various researches 
may be summarised to the following effect : — 

1. Light has a deleterious action on bacteria in their vegetative, 
and, to a less extent, in their spore forms. 

2. The action is not caused by the rise of temperature. The ultra- 
violet rays are the most powerful, and the infra-red the least, showing 
that the phenomenon is due to chemical action. 

3. The effect is greatly increased by the presence of air and 
moisture, so much fo that it is undoubtedly due to a process of 
oxidation, possibly brought about by the agency of ozone or peroxide 
of hydrogen, or both. This view is supported by experiments by 
Richardson,** in which it is shown that peroxide of hydrogen is formed 
in urine dui'ing insolation, and that the sterilising action of light can 
be counteracted by the addition of substances — e.g., peroxide of 

* Zeitschrift filr Hygiene, vol. x., p. 285. 

t CentrcUhlatt f. Balteriol, 1890, pp. 1(J7, &c. X Ibid., 1892, vol. xi., p. 161. 

§ Proc. Roy. Soc., 1893, p. 310. II Brit. Med. Joum., 1894, p. 72. 

IT Ibid., 1893, p. 20. *• Proc. Chem. Soc, 1893, p. 121. 


manganese — which destroy liydrogen peroxide.* Richardson shows 
that the insolation of water alone' does not generate peroxide of 
hydrogen. Dr. Frankland thinks that in the case of dried bacteria, or 
those suspended in pure water, the destruction is occasioned by the 
peroxide formed within their cells. 

4. The action is not generally due to any alteration of the medium 
by light. 

5. The result varies according to the duration of the exposure, the 
intensity of the light, and the nature of the organism. Anthrax 
spores grown at 38° C are much more easily killed by light than those 
obtained from the same source at 18° to 20° C. 

6. There is no evidence that the virulence of anthrax undergoes any 
permanent attenuation through exposure to light. 

7. Anthrax spores are less rapidly destroyed in distilled or potable 
waters than in culture media, or in an isolated condition. Their 
-endurance is particularly long-continued in distilled water in absence 
of air, resistance to upwards of 110 hours' exposure having been 
observed by Momont.f The addition of a halogen salt, such as 
sodium chloride, materially increases the rapidity of destruction, while 
an oxy-salt, like sodium sulphate, has little or no influence. 

8. The efi"ect is much diminished by the rays passing through deep 
layers of water. 

9. Wliilst every opportunity should be afforded for insolation in the 
•construction of water woiks, undue reliance must not be placed on 
this any more than on any other particular bactericidal agency {Percjf 

Professor Esmarch has endeavoured to make use of sunlight as a 
practical disinfectant for skins and furs which cannot be sterilised in a 
steam disinfector. He finds, however, that, as might be expected, the 
light has only a surface action, especially on dark materials, and that 
it is, therefore, valueless when micro-organisms are likely to be present 
in the deeper parts. 


Inert substances have been used (1) for the removal of bacteria by 
mechanical straining or precipitation, (2) for the absorption of noxious 

Carbon. — Animal charcoal, or bone-black, more particularly absorbs 
substances in solution (see Filtration, p. 15). When thrown into 
sewage, especially with clay and other heavy powders, it carries down 
with it almost the whole of the suspended matters into the sludge, and 

* P. FranklanJ, Micro-ortjaniamH in Water, 1894, p. 389. 
t Ann. de I'ln.'-t. Pasteur, 1892, vol. vi , p. 21.. 


also removes sulphuretted hydrogen, ammonia, the ptomaines, and the 
greater part of the other organic compounds, so as to leave the 
supernatant liquid nearly colourless and clear. If it could be used in 
sufficient quantity it would be one of the best of purifiers. It also 
effects a slow oxidation of the matters contained in the deposit, by 
means of the oxygen which most forms of carbon absorb from the air. 
Unfortunately, it is an expensive material, as bones are in great 
demand for manure. A large number of processes, many patented, 
have endeavoured to recover the phosphate by using the sludge as a 
fertiliser, but they have all, so fai', met with little commercial success. 

Vegetable cliarcoal has a still greater power of condensing gases 
within its pores. One volume of wood charcoal will absorb the 
following volumes of different gases : — Ammonia 90, sulphurous acid 
€5, sulphuretted hydrogen 55, carbon dioxide 35, carbon monoxide 
9*42, oxygen 9 •25. Those gases and organic vapours which are capable 
of oxidation, and possibly bacteria, are destroyed when they come in 
intimate contact, within the pores of the charcoal, with the oxygen 
derived from the air. The charcoal should be freshly prepared, or 
should be reheated to a temperature short of ignition, as it rapidly 
loses in power. By the latter means, or, better, by charring again in 
closed vessels, it can be re-vivified many times. Charcoal derived from 
different woods has slightly varying powers of absorption ; as a general 
rule, the more porous it is the greater the activity. Vegetable charcoal 
has less action on liquids than animal, and being lighter than water 
floats on the surface. Letheby, Stenhouse, and others proposed the 
use of gratings containing wood charcoal as ventilators for buildings 
and sewers. They did not, however, prove a success, as they soon 
become exhausted. If the dead body of an animal be buried in 
wood charcoal it decays without putrefactive odour, except that 
ammonia is evolved. "Wood charcoal removes the odour of all 
decaying matter, and has been largely employed to restore tainted 
meat, by placing it in the water used for boiling. Although the taint 
is removed, the food is not thereby rendered wholesome. It may, 
however, be usefully employed when only a slight change has occurred. 

Revill * demonstrated that charcoal is not, in a true sense, an anti- 
septic, since it rather hastens the decomposition of putrescible matters, 
although, by absorbing the products, it renders the process inodorous 
— i.e., it is simply a deodorant. Still it has considerable value for 
cess-pools, water-closets, and dead bodies, when a removal is necessary. 
Goddard tfe Co. in 1887 patented an automatic purifying closet in 
which a mixture of animal and wood-charcoal, under the name of 
"Sanitary Carbon,'' was discharged mechanically on the excreta at 
* Archives g6nir. de Mtd., 1833. 


each discharge. It was said to effectually deodorise the excreta, which 
is true, and by retaining the ammon'ia, to produce a manure of some 
value. On shutting down the lid a sufficient quantity of the carbon 
is scattered over the excreta in the pan beneath at a cost for each 
time of using of one-eighth of a penny.* In all these methods of 
using carbon it is found that, as the ammonia is rather rapidly evolved 
on exposure to air, the substance soon becomes almost devoid of 
nitrogen, and has practically no value as a manure. 

Peat-charcoal is very light and absorbent. Its application has not 
been a success owing to its friability. Powdered coke, being denser, 
possesses much less power, yet it has been j)roposed in many patents 
for purifying sewage, either alone, or as an adjunct to other agents. 
As an instance, Kingzett in 1887 patented the use of a mixture of 
powdered coke and dry clay as a sewage precipitant. He states that 
the deposit can be readily pressed. 

Coke alone has only a mechanical action. 

Soot contains empyreumatic and bituminous matters in small quan- 
tity, and has therefore antiseptic properties due to these ingredients, 
but its power, though rather lasting, is not very great. It is moder- 
ately absorbent. In horticulture it is much used as an insecticide. 
Sprinkled about sewers and drains it removes the odour. 

Coal-dust, being scarcely porous, is almost inert. Natural bitumens 
have long been used for embalming, but a great part of their effect is 
due to the mechanical exclusion of microbes. M. de Mily has recently 
carried out a number of experiments on the use of bitumens mixed 
with chopped rags (100 kilos, of rags to 10 of bitumen for 600 vines), 
to prevent the attacks of Phylloxera and other pests on ground that 
could not be treated with sulphur. The bituminous earth from 
Rhodes, which was mentioned by Strabo in GO B.C., has also been 
recently used for this purpose. The results seem to have been most 

Peat itself when dried is of value for absorbing moisture and, with it, 
noxious emanations. 1 lb. of it (containing 25 per cent, of water) can 
take up seven and a-half times its weight. 100 lbs. of powdered peat 
will absorb 1,438 litres of ammonia. Several i)atents have been taken 
out for incorporating it with disinfectants, for which ptirpose it seems 
at first to be admirably suited for use in stables, Jic. Ernst f proposes 
that peat or moss should be mixed with 2.^ per cent, of iron sulphate 
or phenol, and used for litter, privies, &c.J The odour of stables in 
which peat moss is employed is less than those in which straw is used 
as litter ; on the other hand, powdered peat is now somewhat exten- 

-* Lancet, 1887, p. 886. t Patent No. 2,581, 1882. 

:;: Westknight and Gall, Patent No. 11,011, 1886. 


sively used for dry closets, and has the advantage over earth of 
absorbing the urine. Schroder has also shown that it has a true 
disinfectant action on cholera vibrios, although other pathogenic 
organisms are more resistant. Drs. Frankel and Klipskin * have 
investigated the subject more minutely and have established the fact 
that the comma bacillus when mixed with peat-dust is destroyed in 
about three hours, whilst cholera vibrios may retain their vitality for 
fourteen days, unless the iirine be acid. Dempster t has shown that 
the cholera bacillus cannot live in peaty soil. The addition of super- 
phosphate augments the disinfecting action of the peat, whilst kainite 
has little influence. The authors, therefore, strongly recommend the 
use of peat for isolated dry closets. 

Sawdust, especially the varieties derived from pine wood, is widely 
used, on account of the resinous and aromatic compounds it contains, 
which seem to ozonise the air to some extent, and also give off an 
agreeable odour. It is not a good vehicle for disinfectants, as it is 
not very absorbent, but is used to some extent in country districts 
where there is no water supply for retaining urine in urinals. 

Clay, blast furnace slag, sbale, and dried earth are all used for 
special purposes. 

Infusorial earth, or Kieselguhr, sterilised by being subjected to a 
heat sufficient to cause it to glow, is said by Dr. Habart to be excellent 
as a dusting powder in surgery. It absorbs from five to seven times 
its weight of water. Mixtures of equal parts of the earth and 
salicylic acid, salol, or iodoform, as well as a 1 in 2,000 trituration of 
corrosive sublimate, have proved useful. 

Ashes and Cinders. — In Belgium and Holland the household ashes 
are thrown daily into privies and ditches with the idea of disinfection. 
In Salford, Oldham, and other places, the ashes, vegetable, and street 
refuse were formerly carbonised and used for the same purpose, some- 
times with the addition of charcoal and dry earth, as recommended 
by Parkes. But though the odour is in great part removed for the 
time, and the excreta are solidified so as to facilitate removal, no 
true disinfection is accomplished. 

Gypsum with coal-tar, under the name of poudre de Come et 
Desneatcx, was formerly much employed in France for disinfecting 
wounds. J Gypsum is still sometimes used in stables. Asbestos, talc, 
pumice, in fact any dry absorbent powder, will act nearly as well.§ 

• ZeiUch.f. Hygiene, 1893, p. 333. 
t Brit. Med. Journ., May 26, 1S94. 
t Valpeau, Gnmptes Rendua, 1860, p. 279. 
§ Vallin, Du'mfectants, pp. 41, 56. 


Percy Frankland * states that out of 100 micro-organisms present in 
untreated river water, there were removed by the Water Companies, 
before distribution, in the case of the 

1886. 1887. 1888. 

Thames, 97-6 96-7 98*4 

Lea (East London Co.), . . .96*5 95-3 95-3 

Sand filtration carefully pursued offers a remarkable and obstinate 
barrier to the passage of micro-organisms, and there is every justifica- 
tion in presuming that if disease organisms are at any time present in 
the raw untreated water they would be retained. This was proved by 
experience in the cholera epidemic at Hamburg and Altona in 1892,t 
when in Altona the water was filtered carefully, in Hamburg not. 
Although the original water supplied to Altona was worse than that 
of Hamburg, the deaths in Altona were 221, in Hamburg 1,250, per 
100,000. At the end of 1892 an outbreak occurred in Altona owing 
to a filter-bed breaking down, proving that the slightest imperfection 
in the manipulation is a constant menace during any epidemic. 

Frankel and Piefke studied the rate of filtration, J and came to the 
following conclusions : — 

1. A filter running rapidly soon clogged, and did not properly 
remove bacteria. 

2. The full eff'ect was not obtained until the filter had been at least 
a day in use. 

3. High pressure is inimical to efliciency. 

4. The quicker filter actually passed less water in the course of the 
month than one which was originally slower, owing to the former 
becoming clogged. 

5. Cholera and typhoid were not completely stopped, but the former 
organisms were more removed than the latter. 

6. The slime that forms in the upper layers is the main agent in 
entanfflinsr the bacteria. Sterilised sand did not retain the microbes. 

7. The efl3.ciency was in all cases only relative, not absolute. Thus, 
mixed coarse and fine sand with fine gravel, of a depth of 3 feet 
8 inches, removed 74 per cent.; fine sand, 5 feet deep, 86 per cent., 
and garden earth and peat retained nearly all the micro-organisms, 
but the latter two in practice were too slow § to be of any practical 
value as filtering media. 

Mechanical filtration for domestic purposes can be effected by the 

* Micro-organisms in Water, 1894, p. 124; also Trans. San. Inst. G. B., vol. 
viii., 1886. 

t Koch, f. Hyrj., vol. xiv., p. 393 ; vol. xv., p. 89. 

:;: Zeit.f. Ilyrj., 1890, vol. viii., p. 1. 

§ Report of Massachmetls Board of Health on Purification of Sewage, 1890-93. 


Chamberland filter, or by the Berkefekl modification. The former 
consists of a cylinder of biscuit or unglazed porcelain. The latter is 
made of compressed and baked infusorial earth ; to renew it, it is 
cleansed under running water, put into cold water, which is then 
raised to boiling, and boiled for some time. It is quicker than the 
Chamberland and possibly equally efficacious. If a few litres are run 
to waste, and it be kept in a cool place, and washed and sterilised every 
eight days, no bacteria will find their way through the material.* 

Stone filters are absolutely unreliable.! Asbestos does not long 
continue to retain micro-organisms, J and Drs. Sims Woodhead and 
Cartright Wood, in a recent report, have shown that, with the excep- 
tion of the filters already mentioned, there are none which are of real 
value. The number of bacteria per cubic centimetre (as counted 
under the microscope) has become one of the chief elements in valuing^ 
the merit of a water. Spring waters have superseded river waters, 
and towns, Avhich have hitherto sought water from their own rivers,, 
have had to seek other sources of greater bacterial purity. The 
principal processes of purification are : — (1) Deposition, either natural 
or assisted by the addition of precipitants ; (2) oxidation; (3) the vital 
actions of the microbes, in which "the last word belongs to the 
aerobic, and, therefore, to the most inoffensive." § 

Clark's well-known method of softening water by the addition of 
slaked lime to a water, whereby nearly the whole of the carbonate of 
lime is precipitated, has long been known, not only to soften the water,. 
but also to carry down the greater part of the colouring matter and 
suspended impurities, mineral, organic, and living. Thus at Hampton, 
it has been found to reduce the germs in the Thames water from 
1,437 per c.c. to 177. 

Other Methods. — Among modifications of Clark's expired patent are 
Gaillet and Huet's, which consists in the addition of caustic soda and 
accelerating the separation of calcium carbonate by deposition between 
plates, and Maignen's Anticalcaire, which contains more sodii, sodium 
carbonate, and lime, and throws down nearly all the lime and magnesia, 
of the water. 

Percy Frankland, in a compai'ison of the original Clark's process 
with that of Gaillet and Huet, as tried on the water of the Colne 
Valley Waterworks, found 

Clark, after two daj's subsequent rest, . 
Gaillet and Huet, after two hours, 

* Zeitschr. f. Hyj., 1891, vol. x., pp. 145, IflS ; Freudenreich, Centr. f. 
BakterioL, 1892, p. 240. .i> Esmarch, xhitL, 1892, vol. xi., p. S25. 

J Jolles, ibid., 1892, vol. xii., p. 59C. § Duclaux, Ann. de VInst. Pasteur, 1894. 





per cent. 






SO that the addition of soda very greatly increases the rapidity. It 
must be borne in mind that even if only 2 per cent, of the organisms 
are left the water is not sterilised, "but the subsequent addition of a 
relatively small quantity of a chemical disinfectant would secure such 
a result.* Slow deposition alone diminishes the number of micro- 
organisms present in a liquid. In the passage through two settling 
reservoirs of the New River Co., Dr. P. Frankland found that the 
alteration in the number of germs present was as follows : — 

Germs per c.c. 
Entrance of first reservoir, .... 677 

Exit ,, .... 560 

,, of second reservoir (large one), . . . 183 

Reduction only 27 per cent. 

Buchnert introduced into clean water in repose a number of 
•difterent micro-organisms. £. jjyocyaneus multiplied abundantly, but 
B. typhi and B. coli (the ordinary bacillus of the intestines) died in 
two or three days,; whilst Percy Frankland in Thames water, and 
J. Parry Lawes in London sewers have noticed similar results. 

Duclaux concludes by affirming that putrefaction itself jnirifies, and 
the microbes themselves are the chief purifying agents. It is true 
that although they finally convert putrefying matter into carbonic 
acid, ammonia, nitrates, and water, which are harmless, in the process 
several transition products are formed which are very poisonous. 
Moreover, if they multiply witliin the body they produce disease by 
mechanical irritation, by starving the nutrition, or by excreting toxic 
compounds, such as ptomaines, Ac, into the blood. It is necessary, 
therefore, (1) to keep their numbers within bounds, (2) to exclude or 
kill the specially dangerous ones, (3) in special cases, as in preservation 
of food, to get rid of them altogether. Such an end can be attained 
in the case of sewage effluents, first by accelerated deposition, second 
by chemical disinfection of the clarified water, and, finally, by subse- 
quent irrigation and filtration through land.§ 

Scott Moncriefi" has recently proposed to utilise the micro-organisms 
of putrefaction for destroying the sewage itself, and has patented the 
use of special cultivation beds for this purpose. The process has been 
successfully worked at Towcester, and has been tried at Aylesbury. 


It is well known tliat hot warm climates are the special seats of 
diseases of an epidemic character, and that dry localities, whether cold 
or hot, are comparatively healthy. Moisture and warmth being 

* See also Kruger, Ann. de VInst. Pasteur, vol. ii , p. 621. 

■f Archiv. f. Uyjiene, 1892, p. 184. +See also Schmidt, ih'.d., vol. xiii., p. 247. 

5 Miquel, Analyne Bactiriol. den t'artx, Paris, 1891, p. 139. 


fevourable to the growth of micro-organisms, it might be supposed 
that cold and dryness would prejudice their vitality. To a great 
extent this is the case. In 1871, Burdon Sanderson showed that ice- 
water from the purest ice contained bacteria.* lanowski proved that 
snow even at - 3-9 to — 16" C. contained living micro-organisms,t 
Schmelk found the same in snow from a glacier in Norway, J Fraenkel 
in ice supplied from a lake near Berlin. § Pictet has also shown that 
the temperature of liquid air had no germicidal action. It has thus 
been shown that cold alone will not kill many bacteria ; it remains to 
see how far desiccation is effectual against them. In sandy deserts 
it is common to find corpses dried and free from putrescence ; food 
can also be dried, and if kept protected may be preserved for an 
unlimited time. Herbs and vegetables are thus desiccated and ren- 
dered free from fermentation. Some plants, even when dried, revive 
when they come to a moist spot, and there are well authenticated 
cases of mummy wheat having germinated. Desiccation thus seems 
to suspend the vitality of seeds, and not to destroy it. This is true 
for germs ; when perfectly dry they remain for the time sterile and 
inoffensive, and seeiTi to be subject to aei'ial oxidation ; but if, by the 
winds, or other agencies, they are carried in time to a moist situation, 
like a body of water, a plant, a human skin, or, still better, a mucous 
membrane (such as that of the lungs), they at once revive and com- 
mence to develop. 

The utility of the Eucalyptus and other trees in marshy districts is 
partly due to their absorbing and exhaling the moisture of the soil. 
Siccative powders, like starch and steatite, are known to be useful in 
surgery. Many epidemics have suddenly ceased when a dry season 
has set in. 

Both Koch and Klein have proved that the spores of most of the 
common species of bacteria resist drying for an indefinite period. 
Klein kept the spores of various potato bacilli — e.g., Peronospora 
infestans (the potato blight). Bacillus anthracis, the hay bacillus, and 
those of scurf and jequirity, in culture tubes of agar agar in a per- 
fectly dry state —i.e., in a closed bell-jar over oil of vitriol — until the 
medium had dried up to a thin shrivelled film ; and yet, even after 
two years and a half, on inoculating fresh materials from the above 
tubes, typical and good growths were obtained. On the other hand, 
non-spore-bearing bacteria — e.g., various species of Staphylococcus, 
Streptococcus — bacilli of typhoid, swine fever, swine erysipelas, Koch's 

* Thirteenth Be port of Med. Off. of Privy Council. 

fCentr.f. Bakteriologie, 1888, vol. iv., p. 547. :J/6Jd., p. 547. 

%Ze\tachr. f. Hyg., 1886, I., p. 302. See also Heyroth, Arbeit. Kais. Oeaund., 
vol. iv., 1888. 



and Finkler's bacilli, bacilli of pneumonia, fowl enteritis, chicken 
cholera and grouse disease, as well as a number of others, Avere kept 
as agar cultures until the latter had well dried up. No sub-cultures 
could be raised from any of them. In other experiments tliey were 
dried in a current of air, or by simple exposure in a thin film on 
cover glasses in the manner employed by Koch, leaving them pro- 
tected from dust till dry. No growth of the non-sporiferous species 
could be obtained in gelatine. If the drying is not complete, that is 
if the film be too thick, so that the superficial layer forms a protective 
coating for the rest, then the result of inoculation with such material 
will be positive ; the bacteria below the surface, having been protected 
against drying, survive, and can produce a new crop. Similarly, when 
particles of solids containing bacteria are dried, it will be found that 
here also the centre escapes thorough drying, being protected by a 
superficial crust. Ordinary dust particles, however small, are never 
so dry that the bacteria contained in them are killed. The proof of 
this is that numbers of non-spore-bearing bacilli and micrococci can 
be cultivated from the dust of an ordinary room.* 

Dempster has joointed out that cholera vibrio?, whilst they can 
survive in moist soil, quickly die when the land is dry.t 

Dr. Buchner J says that in the dust of a room B. tuberculosis has 
been found alive a year after the patient died. But he does not 
believe that the virus of typhoid or other fevers ever enters the human 
body through the respiratory tract. 

Provisions that have been smoked and dried may yet contain, nob 
only micro-organisms, but also the ova of Trichina and worms. 
Pemmican, the dried and powdered beef of the prairies, has been 
said to communicate disease. If the meat, however, has been 
thoroughly soaked in a preservative like pyroligneous acid, and then 
dried, it is usually free from danger [Koch). Dry heat and superheated 
steam as disinfectants will be further considered in detail in a subse- 
quent Chapter. 

* Klein, Stevenson, and Murphy's Hygiene, 1893, pp. 11, 81. 
t Brit. Med. Journ., March 26, 1894. 
X Ohio San. Record, April, 1894. 




Heat as a Disinfectant : Conditions required in a Disinfector — Modes of dealing 
with Condensation on Goods— Time and Steam Condition required for Dis- 
infection — Experiments on the Penetrating Power of Steam — Types of 
Disinfectors : English, French, Danish, German, American— Public Installa- 
tions, English and American. 

Heat as a Disinfectant. — It has been found in practice that there are 
cases in which chemical disinfection is not suitable, owing to the 
fact that many chemical disinfectants are very apt to cause damage to 
the articles treated, and also that their action frequently involves pro- 
longed exposure, and is even then only superficial in its effect. For 
instance, the usual mode of disinfecting a room which has been occupied 
by a person suffering from an infectious disease, is to close all outlets 
and burn a given weight of sulphur therein for a period of several 
hours. But if this treatment be applied to such things as heavy 
"woollen clothing its effect is practically 7iil, as may be readily shown 
by a very simple test. It has been found that a bright shilling, when 
exposed in a room subjected to fumigation by sulphurous acid, is 
immediately tarnished, but a similar coin wrapped up in a hand- 
kerchief or placed in the pocket is not discoloured in the slightest. 
It is fair to argue from this that, in the instance cited, the action of 
the disinfecting gases has only been superficial. The chemical treat- 
ment of the room is justifiable on the ground that in all probability 
surface disinfection only is required in dealing with substances like 
wood, bricks, and iron, it having been assumed that all permeable 
articles, such as carpets, curtains, &c., have been previously removed 
for more complete treatment. It is, however, open to doubt whether, 
even in this case, chemical treatment would be resorted to were it 
practicable to apjily disinfection by heat. 

For the reasons that have just been stated it has become usual not 
to attempt the disinfection of such articles as clothing, bedding, carpets, 
«Skx, by chemical means, however invaluable such means have been 
proved to be when applied to other cases. It would appear that 
the inti*oduction of heat in some form or other for purifying purposes 
would be an obvious step to take, but it must be remembered that 
nearly two centuries ago, disease germs considered as organisms of 
any kind, still less as bacteria-bearing spores, were then unknown, 


and, if their existence had even been suspected, considerable experi- 
mental proof would be required to show that a temperature below 
that at which articles of clothing would be damaged or weakened in 
their fibre, would be sufficient to destroy all danger of infection. The 
work of Needham, therefore, during and before 1743, must be looked 
upon with admiration, since it was he who first recorded experiments 
in a systematic manner involving the use of heat with the object of 
sterilising organic substances. His cultivations, as they would be 
termed to-day, were placed in carefully-closed vessels surrounded by 
fire, and his experiments led him to conclude that such treatment 
rendered growth impossible. Curiously enough an after-growth in the 
sterilised cultivating medium made him a convert to the theory of spon- 
taneous generation, and it was in reference to this theory, the crucial 
debate of the age among scientific men, that the publication of his 
experiments was due.* Needham's great opponent, Spallanzani, in 
reference to the same theory, also took up the question of sterilisation 
by heat ; he even went so far as to detect the difference between dry 
and moist heat, and showed that in some instances animal life was 
impossible in water at 45° C, whereas the same cultivations were not 
destroyed by dry heat at a temperature less than 80° C. 

In 1804, Appert discovered that meat, vegetables, ic, when placed 
in carefully sealed receptacles, and dipped in boiling water for an hour, 
would keep indefinitely without putrefaction or fermentation. This 
process was very carefully reported on by Gay Lussac (at the request 
of the French Government), who, owing to these investigations, 
expressed the opinion that no oxygen was present in the sealed vessels 
after the process, and that the absence of this gas was essential to the 
preservation of animal or vegetable tissue; but it was noteworthy that, 
although this brochure was for long regarded as the standard work 
dealing with the subject, no mention whatever was made of the 
destruction of germ life within the vessel. 

It is generally believed, however, that the earliest application of 
heat to disinfection on a large scale, as opposed to the laboratory 
experiments of Needham, Spallanzani, (fee, was not made public until 
Dr. Henry, F.R.S., of Manchester, gave an account in the Philosophical 
Magazine for 1831 of some experiments he had made on the disinfection 
of infected clothing by hot air. A steam jacketted copper was used, 
into the casing of which only steam at 212° F. was admitted; but, 
apparently, it was found impossible to heat the interior to much more 
than 200° F. with these appliances. Dr. Henry's results, so far as they 
went, were encouraging, and tended to show that the clothing of 

* See La giniration spontanAe, by I. Strauss ; Arch, de m6deciue expirimtntcUe, 
t. 1", pp. 139-156 and 329-348. 


scarlet fever patients, which had been submitted to a temperature of 
200° F. for two to four hours, would not propagate the disease if worn 
by other healthy persons. Most of Dr. Henry's experiments, and 
even of those of Dr. Baxter in 1875, were made with vaccine lymph, 
and it was really not until the expei-iments of Pasteur, Lister, Burdon 
Sanderson, Tyndall, and Koch had been published, that suflScient 
data concerning the reality and nature of bacteria existed to render 
it possible to test the efficacy of heat, dry or moist, as a destructive 

The results of Tyndall's experiments (communicated to the Royal 
Society in 1876 and 1877, and also contained in his well-known book, 
entitled Floating Matter of the Air) were remarkable, inasmuch as they 
treated the subject lai-gely from the physicist's standpoint. In this 
work he proves conclusively how very variable is the treatment, both 
as regards duration and intensity, of the heat essential for the 
sterilisation of organic matter. He showed, for example, that hay 
infusion might be kept continuously boiling for several hours and yet 
not be sterilised, inasmuch as the spores could resist such treatment 
and develop subsequently, although the original mature bacilli would 
have all been destroyed. As a proof of this he boiled similar infusions 
intermittently for a couple of minutes, twice or three times during a 
day or so, and found that, although the total period of actual boiling 
might be less than six minutes, compared with the hours of the 
previous case, no aftergrowth whatever appeared in the prei)aration. 
Tyndall also pointed out, and proved in some cases, that oxygen was 
an essential to the existence of micro-organisms. He found that 180 
minutes continuous boiling failed to sterilise a turnip infusion in the 
presence of the ordinary supply of air, but that ten minutes at 212° F. 
sufficed to produce absolute barrenness, when such heating was con- 
ducted in absence of air. The production of a vacuum was found to 
be such an important factor in sterilisation that experiments were 
made to ascertain whether the total absence of oxygen would in itself 
be sufficient to effect destruction, and in so many instances was this 
found to be correct, that the conclusion was arrived at that, with suffi- 
ciently perfect exhaustion, all infusions would probably be sterilised.* 

The views of Tyndall, in reference to the necessity of oxygen for the 
propagation of microbes, have since been much modified by the 
experiments of later observers, who discovered that a small class of 
bacteria, called " obligatory anaerobes," could only exist in the absence 
of oxygen, and that others, " facultative anterobes," increased most in 
the presence of free oxygen, although it was possible for them to exist 
in the absence of this gas. The latter class is the larger of the two, and 
• Comptes licndus, vol. Ixxx., p. 1579. 


includes many pathogenic organisms, such as the Bacillus anthracis, 
and the bacillus of Asiatic cholera. There is also a third class, 
" obligatory serobes," to which the presence of oxygen is an absolute 
necessity. The observations of I'yndall are, in this respect, not per- 
fectly accurate, although it is probable that his conclusions would hold 
true for the larger number of cases for which disinfection is required, 
insomuch as clothing is constantly aerated, and, therefore, should, 
under ordinary conditions, contain no living obligatory anaerobes. 

The foregoing results are of the greatest importance from the prac- 
tical standpoint, as will be seen later on. They paved the way for 
further progress at the hands of Koch, Pasteur, and others.* Koch 
made his experiments on ^jure cultivations of (1) non-spore-bearing 
organisms, such as the Micrococcus prodigiosus ; and (2) of spore- 
bearing kinds, such as anthrax bacilli, &c. He attempted disinfection 
by chemical agency, hob dry air, and by steam ; moreover, in all these 
cases the trials were eventually made on a sufficiently large scale, with 
bedding, &c., to make his results of the greatest value. He confirmed, 
generally, the result of previous workers that the spores were the 
most difficult to destroy, and that, therefore, if they be devitalised, 
all bacteria will also have been rendered harmless. In dealing with 
hot air he found that spores were only destroyed by being exposed 
at 284° F. for a period of three hours, but that at this temperature t 
almost all fabrics which require disinfection are already injured, 
a,nd that the rise in temperature inside a small roll of blankets so 
exposed was not sufficient, unless the exposure was continued for a 
much longer period. When steam at 212° F. was used as a disinfect- 
ing agent, Koch found that anthrax spores, when freely exposed, were 
killed in five minutes, and that even with steam at atmospheric pres- 
sure, penetration of heat through blankets took place in about one- 
quarter of the time necessary to secure a sufficient internal temperature 
when hot air alone was used. From the medical point of view, these 
experiments were most satisfactory, although, owing to the crude 
nature of the apparatus used, it would appear that most, if not all, 
the articles treated were considerably moistened and in some cases 
damaged by the action of the steam. 

Hoch and Wolf hiigel + conclude that " dry heat, even continued for 
two hours at 150° C, did not always assure disinfection, although 
nothing resisted, even for a few minutes, boiling water or steam at 
100° C." Gaffky and Loffler§ summarise their experiments as 
follows : — 

* Mittheilungen aus dew. K. Ge^undheitsamte, vol. i., p. 188. 

+ See also Brit. Med. Journ., September 6, 1873. 

J Mitt. a. d. Kais. Gesundh., 1881, p. 301. § Ibid., p. 322. 


1. Non-spore-bearing bacteria cannot endure for one and a-half 
houi-s an exposure to hot air at 100° C. 

2. The spores of mould are not killed by one and a-half hours 
exposure to hot air at 110° to 115° C. 

3. The spores of bacilli are only killed by three hours exposure to 
hot air at 140° C. 

Bonhoff and Foster * state that Bacillus tuhercvlosis at 60° C. dies 
in one hour, at 90° C. in five minutes, and at 95° C. in one minute. 

The experiments of Dr. Klein and Dr. Parsons, as detailed in the 
Annual Report to the Local Government Board for 1884, confirm very 
largely those of Koch, and they also deal with the question of practical 
disinfection in a manner that renders this work of very great value. 
The great advantages of steam over hot air were demonstrated very 
clearly, and, owing to the number and diversity of their experiments, 
they were able to show that, in some cases at all events, the action of 
steam in a suitable apparatus was not in itself injurious to the articles 

The work of Pasteur, Tyndall, Lister, Koch, Parsons, and others 
has, therefore, determined the fundamental conditions for successful 
disinfection by heat. 

Conditions required in a Disinfector. — It remains to be shown that 
the mechanic can meet the requirements of the bacteriologists, and, at 
the same time, deal with the practical difficulties that invariably beset 
him during the introduction of novel machinery. The conditions for 
dry-heat disinfection, so far as tempemture and duration of exposure 
are concerned, have not been very clearly defined; but from experi- 
ence gained by Dr. Hopwood at the London Fever Hospital, it may be 
gathered that an exposure of bedding to hot air at a temperature of 
250° F. for a period of nine hours is generally sufficient, and no 
material damage is caused thereby to the goods. 

The great difficulty in designing a stove to fulfil these conditions 
arises from the fact that it is almost impossible to obtain a uniform 
equable temperature in a sufficiently large chamber. It is probable 
that exposure to air at a temperature of 260° F. for nine hours weakens 
many woollen materials, and a temperature of 280° F. distinctly dis- 
colours them, whereas an error of 10° or 20° F. on the lower side of 
250° F. renders disinfection by these means more doubtful. The 
allowable range of temperature in a hot-air disinfector should, there- 
fore, not exceed 20° F., and the mean should be about 250° F., since, 
according to Drs. Parsons and Klein, the free exposure of anthrax 
spores to air at 245° F. for one hour suffices for their destruction. 

Most engineers are well acquainted with the great difficulty met 
• Hyj. Rinid*(hau, vol. ii. , p. 869. 


with in heating air to a uniform temperature, and the problem is not 
made any the easier by the fact that in such places where hot- air 
machines are now required, steam is not available for heating the air. 
If it were available, there can be "little doubt but that it would be 
employed for the actual disinfection without the aid of air. As a 
rule, coal and gas are the only sources of heat available for the pur- 
pose, and even then, seeing that it is merely in the smallest and most 
out of the way districts that hot-air disinfectors are permissible, the 
first cost of the apparatus has to be kept so low that adequate tem- 
perature regulating becomes almost impossible to provide for in a 
chamber of the requisite size. It must be remembered that although 
local conditions may make it excusable to erect hot-air apparatus, the 
size of the hospital or population of a district does not determine the 
capacity of the hot chamber, for it must be large enough to contair» 
the largest article that it is likely to have to disinfect (usually a double 
mattress) without being folded. In dealing with hot-air disinfection 
it becomes especially important to arrange the articles in such a manner 
as to reduce to a minimum the distance through which heat has to 
penetrate, and, therefore, bulky things, such as mattresses, should 
never be folded, and if several have to be treated at once, each should 
be separated from its neighbour by wooden strips to allow of 2-inch or 
3-inch air space. 

Seeing that mattresses should not be folded, owing to the diminution 
in penetrative effect of the heat, and frequently cannot be folded or 
bent without damaging their construction, we can at once fix upon a 
length of 6 feet as a minimum for the chamber, or if this be not 
practicable, the diagonal should not be less than this, if, as is generally 
possible in a hot-air chamber, a rectangular section can be used. One 
dimension being fixed at 6 feet as a minimum, another may be deter- 
mined in a similar manner by the width of the mattress. In hospitals 
or public institutions beds do not commonly exceed 3 feet in width, 
but private household mattresses very commonly exceed 5 feet. It 
may, however, be assumed that in the future no 2^ublic hot-air dis- 
infectors will be erected, and that their very limited scope will be 
confined to small workhouses or institutions ; hence, after allowing for 
a small margin, a depth of 4 feet should sufiice. The depth and length 
being fixed respectively at 4 feet and 6 feet, the width may be fixed 
according to circumstances depending on the number of mattresses or 
clothes likely to require disinfection at one time. Thus four mattresses 
each 6 inches thick would require a chamber 3 feet 6 inches wide, after 
making sufficient provision for air space between each unit. As a 
matter of fact the smallest really satisfactory hot-air disinfecting 
chamber usually erected in this country is 4 feet 6 inches long, 4 feet 


6 inches high, 4 feet 6 inches wide internally, and in this an ordinary 
3 feet X 6 feet mattress must be placed diagonally. This is a very 
unsatisfactory arrangement, owing to the available space being so much 
cut up, and also because the ends of the mattress rest actually in the 
angles of the chamber where it has been ascertained a certain quantity 
of "dead" air (i.e., unchanged or stationary air) generally remains at 
a temperature considerably lower than the average throughout the 
closet. The latter objection is in reality one common to most dis- 
infectors of rectangular section, but if the chamber be of ample size, 
these dead air spaces need not actually be occupied by portions of the 

The question of air circulation through the chamber is probably one 
of very great importance, for not only does it tend to promote 
uniformity of temperature by admixture of gases of different tempera- 
tures, but also it has been found that gases in motion can be more 
readily heated by a hot surface owing to their rubbing action, and 
conversely, that moving heated gases can part with their heat more 
readily to cold surfaces than when they arc at rest. In all hot-air 
stoves there is, of course, a certain risk of overheating the goods, and 
in most cases they are temporarily weakened, and perhaps rendered 
brittle, immediately after their removal, although these latter defects 
usually disappear after the articles have regained their normal 
hygrometric moisture; possibly this does not occur in such disinfectors 
as have water pans exposed in the hot chambers. Precautions have 
also to be taken to damp a tire in the chamber should it occur, owing 
to the presence of lucifer matches, in spite of the fact that a careful 
attendant can always search for and remove all sucli dangers from the 
pockets and linings of garments, ikc. The danger against fire is very 
usually guarded against by placing some fusible links in a chain 
stretched across the interior of the chamber, which chain is so con- 
nected to a damper that when broken, the latter closes the exit to the 
chamber, and thus the fire is automatically gradually quenched through 
lack of oxygen. The same device is also commonly geared to close the 
gas sujjply, if it be a gas-heated machine ; but it must be noted the 
arrangement is one which only comes into action after the evil has 
arisen, and does not protect clothing from damage, but merely checks 
the extension of fire. Dry-heat machines are likely to be little used 
in the future, and it is, therefore, unnecessary to describe them at any 
length. Dr. Parsons' Report of 1884 gives full particulars of the 
several types then in use. Dr. Parsons found that very few, if any, 
fulfilled all the conditions required for adequate disinfection, although 
he mentions Bradford's apparatus as being the best coal-fired dis- 
infector, and the invention of Dr. Ransom as being a very suitable 



gas-heated machine. The former contained an exposed dish of water 
during Dr. Parsons' experiments, whereas the latter did not; although 
there is no apparent reason why such an addition should not be made 
if found advantageous. In the Bradford apparatus, a range of 
temperature of 24° F. was found to exist throughout the chamber, the 
maximum being about 248° F. The moistening of the air was found 
to have an appreciable effect in aiding the penetration of the heat, and 
thus diminishing the period of exposure, and in Mr. Bradford's opinion 
it also tended to preserve fabrics from injury at high temperatures. 

filmiBmiiiHiiiS iiiiiiiiiiinjiiiiiiiiiiiiiiiliiiriiluLiiiiiiliii'irMrlliillilliliiiiiiiiiiiiiiiiniii.iiiiiiiiiiiiiuiiiiilliiliiiirliiiliiiiiHiiiii imc 

Fig. 1. — Bradford's Hot- Air Disinfecting Apparatus. 

On the other hand, it is clearly difficult to so stoke a firo as to produce 
a uniform temperature in a large chamber (even opening the furnace 
door caused a drop of temperature in the chamber of 7° F.), and the 
success, or otherwise, of the process, therefore, largely depend 
upon the skill and attention over several hours of the person in charge. 
"No experiments appear to have been made with microbes in either 
machine, so no definite proof is given that moist air at about 230° F. 
has absolute germicidal properties, if continued for two hours only. 
The construction of one form of this plant is given in Fig. 1. In Dr. 


Ransom's apparatus, which is heated by gas, the temperature may be 
automatically governed by means of the now well-known mercurial 
regulator, and on trial a variation of 9° F. was recorded in the 
chamber, the minimum being 247° F. Although the time taken to get 
up the requisite temperature and disinfect is considerable, the 
apparatus can be left with safety to work without attention owing to 
the gas regulator, and, in consequence, the drawback is much 
minimised. In this case also, a constant stream of heated air passes 
through the machine, which, no doubt, tends to preserve uniformity of 
temperature, and perhaps accounts to some extent for the better 
results than can be obtained in a coal-fired apparatus. 

The chief drawbacks to hot-air disinfection are, therefore, due to 
the slowness, and the danger of damaging the goods. It has also been 
found that the process offers facilities, or even encouragement, to the 
man in charge to scamp his work, for one can rarely tell by the 
appearance that articles have been disinfected or not, and so great is 
the risk of articles firing or being singed, if subject to a temperature 
of 250° F. for several hours, and thus bringing the attendant into 
trouble, that, as often as not, he takes the precaution never to allow 
it to exceed 200° F. In one instance, at a dry -heat disinfecting 
station in a densely populated London district, the attendant actually 
prevented the air rising above 190° F. because expenses have been 
incurred in the past for the replacing of damaged clcthing. This 
farce has been going on for many years, and had not been altered in 
1894. Such a state of things would be almost impossible if steam were 
used, and, moreover, there exists no such temptation, for there is no 
danger of damaging the clothing by heat in a well-constructed steam 
apparatus, and the required temperature is obtained independently of 
the attendant after his steam valve has once been opened. The 
superior germicidal and penetrative qualities of steam have already 
been referred to, and the only drawback to its adoption is that, unless 
proper precautions are taken, the steam may condense on the articles 
in sufficient quantities to damage them, and to necessitate drying 
subsequent to their removal from the machine.* 

Modes of Dealing with Condensation. — This question of condensation 
roughly divides the several types of steam disinfecting apparatus into two 
classes, viz., firstly, those in which provision is made to prevent copious 
condensation by keeping the walls of the chamber at a higher tempera- 
ture than the steam inside ; and, secondly, those in which no such 
provision is made, and which frequently necessitate, as a consequence, 
the subsequent drying of goods. Each of these classes might be 

* See v. Esraarch, Zeksch.f. Hyg., Bd. iv. ; Graber, Oesundheits ingenieur, 18S8; 
Badde, Archiv.f. Hyg., lid. ix. 


further subdivided into several others determined by the pressure of 
the steam admitted to the chamber, by the currency or otherwise of 
the steam in contact with goods, and by the introduction or addition 
of apparatus necessary to create a vacuum in the chamber. Special 
apparatus has also from time to time been made to overcome special 
diflBculties, such as arise Avhen heavy bales of rags or merchandise 
have to be treated in large quantities. The usual practice at home is 
to erect a machine in which condensation is prevented l)y means of a 
steam jacket or outer casing surrounding the chamber containing the 
articles to be treated, and into which steam is admitted at a higher 
temperature than that passing subsequently into the chamber. The 
walls of the chamber being retained thereby at a higher temperature 
than the steam admitted, condensation of the latter, due to contact 
with cold walls, is absolutely prevented; but it must be borne in mind 
that however valuable Washington Lyon's invention may be, it does 
not absolutely prevent condensation on the goods themselves, which 
are cold when first admitted, and only slightly warmed on the surface 
by radiation from the hot sides and air convection due to the same 
cause. There is, therefore, an initial condensation on the surface of most 
goods when first brought into contact with steam, and consequently 
a rise in temperature owing to the reception of the latent heat of the 
steam during liquefaction. The fresh steam which next comes into 
contact with the goods does not condense so largely, because they are 
at a higher temperature than before ; but, nevertheless, liquefaction 
does occur, and the articles again rise in temperature. This cycle of 
operations repeats itself again and again rapidly, but finally the whole 
of the articles are at the same temperature as the surrounding steam 
and no further condensation occurs. The influence of the jacket then 
becomes of greater importance, for it heats the steam, and no steam is 
being condensed. The consequence is that the steam becomes super- 
heated (the safety and reducing valves keep the pressure constant) and 
is always kept in circulation by the convective effect of the sides ; the 
result is that whatever moisture the goods may hold is re-evaporated, 
so that they may be taken out substantially dry. It would appear, 
perhaps, from the foregoing description that many delicate fabrics 
would be damaged by even the temporary condensation at the com- 
mencement of the process; but it is found iu practice that sur])risiDgly 
little injury is done ; even the colours in cheap cotton print show no 
signs of running, while delicately-tinted silk dresses are but little 
affected by the condensation. Some materials lose their gloss, and 
certain other woollen goods, such as new blankets, take the slightly 
yellow tinge that would generally follow a good washing ; the only 
goods which are absolutely damaged are those made of leather, or fur. 


These latter should always be treated by dry heat, or other means, 
and the same remark generally applies to varnished or glued wood- 
work, although heat of either sort when applied to finished woodwork 
almost invariably leaves a record of its application of a more or less 
serious nature. 

Time and Steam Conditions required for Disinfection. — The precise time 
required for disinfection in such a machine as has just been described 
depends on three main factors — viz., firstly, on the particular disease 
germ that it is required to kill ; secondly, on the nature and bulk of 
the articles supposed to contain the germs ; and lastly, on the steam 
pressure employed to secure penetration into the goods. It is, of 
course, impossible to say whether any article contains only one species 
of microbe, and also it is very frequently found to be practically 
advantageous to treat at one operation the clothing, &c., of patients 
suffering from several distinct maladies. As it also sinijilifies the 
routine work of the attendant to have only one basis on which he may 
calculate the total time required for disinfection, the minimum time 
generally adopted should be that required for the steam to kill the 
most persistent microbe when unprotected by foreign and artificial 
surroundings. According to Dr. Klein and others anthrax spores have 
hitherto been found to be among the more persistent forms of organism 
affecting human beings, and, judging from their experiments, it may 
be said that a free exposure to saturated steam, at 212° F. for fifteen 
minutes, was a period in which sterilisation could be effected with 
certainty. It was found that five minutes exposure under the same 
conditions gave doubtful results, and, therefore, it is probable that 
absolutely safe disinfection cannot be effected with steam under less 
than ten minutes free exposure. This period was also found just 
suflicient to kill lice and their eggs, for which purpose these machines 
are sometimes almost entirely used in such places as workhouses. The 
germicidal effect of saturated steam at a higher pressure of, say, 15 or 
20 lbs. per square inch is usually supposed to be greater than that of 
steam at atmospheric pressure ; in fact. Dr. Klein considered that its 
efficacy might be taken for granted, and, therefore, made no experi- 
ments of a similar nature by its aid. There is, however, one point to 
which attention should be drawn ; steam may be either " saturated " 
or " superheated," but the germicidal influence of the two is considered 
by many to be different, although the steam is dry in both conditions, 
and either form may exist at any pressure or in the absence of water. 
These two facts are mentioned, because in the minds of some saturated 
steam is commonly associated with moisture, and sujjerheated steam is 
confused with steam under pressure. The two forms are distinguished 
entirely by their temperature — that is to say, steam may just exist at 


227*95° F. under an absolute pressure of 20 lbs. per square inch (i.e., 
including atmospheric pressure), or by adding more heat to it, its 
temperature will rise, say, to 300° F. at the same pressure although 
its volume will increase, and in this condition it is said to be super- 
heated. In most, if not all, steara-jacketted machines the earlier 
portions of the operation must perforce be conducted with saturated 
steam, and in the better machines, from which the articles come out 
absolutely dry, it is probable that the steam contained in the chamber 
becomes slightly superheated towards the end of the process. Hence, 
it matters but little in a jacketted machine whether saturated or 
superheated steam be the better disinfecting agent, for steam may be 
used in both conditions. As a matter of fact, the difficulty has always 
been to bring the articles out dry, and so long as they come out with 
even ^ per cent, added moisture, it is certain that the steam has never 
been entirely superheated. 

The question of steam pressure to be employed is one which has 
been much debated, and at the present time there are machines (mainly 
on the Continent) which employ steam at 1^ lbs. pressure ; and others 
again working with steam at 20 lbs. pressure. Assuming, for the sake 
of argument, that the higher pressure steam has no greater germicidal 
effect than the lower (which is not probable), it still has many im- 
portant practical advantages which are of great value in most cases. 
When bulky articles, such as mattresses, rolls of carpets, &c., have to 
be treated, or when the machine must be filled so entirely that the 
air space between each article almost disappears, then it is clear that 
penetration of 20 lbs. steam will take place far more rapidly than if 
this pressure be only 1 or 2 lbs. Or, again, a machine which uses 
steam at 20 lbs. pressure may be worked off almost any existing boiler, 
because almost all steam generators nowadays work at pressures above 
that required, and, although it is a comparatively simple matter to 
reduce the pressure automatically to 20 lbs., it is not nearly such an 
easy problem to reduce the pressure sufficiently so that the steam may 
be used with safety in apparatus designed to stand 1| lbs. only. This 
difficulty may entail the erection of a special lx)iler of unusual design, 
and steam is then raised under conditions the reverse of economical. 
It is also noteworthy that condensation is more likely to take place 
when low-pressure steam is used than when steam at a higher tempera- 
ture is admitted. The main objection to high-pressure apparatus is 
that the machines require not only greater strength, but also more 
careful design, and are consequently more costly. There are occasions, 
doubtless, when, on economical grounds only, the low-pressure machine 
is allowable; but the circumstances, even in these cases, should be 
such that time for drying articles can always be allowed subsequent 


to treatment. Although steam can, as has already been shown, pene- 
trate the bulkiest article in a comparatively short time, this period 
may, by a little manipulation on the part of the attendant, be very 
materially reduced. In arranging the goods in the chamber, every 
care should be taken to leave a little space l:)etween each of the various 
i-olls or bundles. Often a few ])ieces of wood or a rough hurdle may 
come in very useful when articles have to be piled one on the other, 
or things can be hung up readily so as to allow of circulation. In all 
cases it is safest not to permit the attendant to handle infected articles 
more than is absolutely necessary ; therefore, bundles or rolls ought 
not to be themselves unpacked, although such a proceeding would 
undoubtedly hasten the process. Again, after the chamber has been 
closed (assuming it to contain bulky articles), penetration may be 
greatly facilitated by relaxing the pressure and refilling several times 
during the process. Thus, if the chamber be filled with steam at 
20 lbs. pressure in two minutes, this steam may l)e allowed to remain 
stagnant for say tAvo minutes, and then allowed to escape. It should 
immediately be refilled with steam, and perhaps five minutes later 
again allowed to escape, and so on. It is probable that this procedure 
is advantageous owing to the large amount of air retained in woollen 
and other goods, which is compressed by the steam into their centre, 
and if not allowed to distribute itself throughout the chamber by 
removal of piessure, would greatly retard penetration. It has been 
found that rolls of blankets, rolls of carpets, and compressed bales 
are among the most difficult articles to disinfect, and in such cases 
the precautions just referred to should most certainly be adopted. 
Mattresses and pillows can readily be separated one from another, but 
if this be not done, considerable time may be required for these also. 
There is still one difficulty which arises when heavy charges are placed 
in the machine, and that is due to the internal condensation in the 
centre of the goods. The explanation of the causes promoting con- 
densation will have made it clear that such difficulties will be more 
difficult to eradicate in large bundles than in small ones ; and, as a 
matter of fact, it is generally the rule that moisture will be perceptible 
in the centre of a large roll in spite of the steam jacket. It is clear 
that condensation may be entirely avoided in the first place if the 
goods be raised to the temperature of the incoming steam prior to its 
admission ; but it has been shown that in dry-heat stoves it is a very 
lengthy operation if the goods be bulky. The length of time is due 
very largely to the fact that the hot air is not forced into the centre of 
the goods ; in fact, it has little more than a surface action, and, as a 
consequence, the goods usually act as a capital non-conductor to protect 
the interior, and the cold air retained there. But if we assume that 


this contained cold air could be withdrawn, and the hot air subse- 
<|uently forced in to take its place, we get a very different state of 
things, and the heating can obviously be effected far more rapidly. 
This course is practicable if steam be available, for the removal of 
air and the compulsory substitution of other heated air al)sorbs more 
work than could be expected from an attendant if steam power were 
not at hand, as is the case when dry-heat disinfectors are employed. 

The whole process may be completed by merely creating a vacuum 
in the chamber and then admitting heated air at atmospheric pressure. 
It is a very simple matter to withdraw the bulk of the air by a simple 
steam jet arranged after the fashion of the ordinary spray producer 
until a vacuum of 20 inches is indicated on the gauge ; and then, if 
the chamber be placed in communication with the atmosphere, air is 
forced in at a pressure of about 10 lbs. to the square inch, and, in 
transit, it may be passed through a short coil of pipe surrounded by 
steam at the required temperature so as to heat it to the most suitable 
degree. There are many features about this process to recommend it ; 
for, not only is it possible to regulate the temperature of the incoming 
air to a nicety, but it is also itself easy to heat, because it is constantly 
in motion, and, for the same reason, the hot air itself heats the goods 
it comes in contact with the more rapidly. If the air be passed through 
pipes heated by the direct heat of a fire, it becomes almost impossible 
to control its temperature, and the same dangers of scorching arise as 
■were found by the use of dry heat stoves. In the class of apparatus 
described it has been found desirable to keep the temperature of the 
incoming air to about 220° F., so that, when steam is admitted at 
250° F., it does not become superheated, and its germicidal influence 
is not affected. Supposing, for the sake of argument, that moisture 
still remains in goods after steaming, the presence of the vacuum and 
hot-air apparatus is still of great value ; for by its aid the articles may 
be dried to any extent desirable at a far lower temperature than 
"212° F. The vacuum has several other advantages quite apart from 
its drying qualities. It enables the operator to remove most of the 
air from the chamber before the admission of steam ; consequently, 
the ordinary steam pressure gauge may be read accurately as a 
temperature gauge, seeing that the mixture of steam and air has not 
to be considered, whereas the temperature of saturated steam varies 
with its pressure. 

Also, the production of a good vacuum * prior to the admission of 

* The term vacuuyn is not intended to implj' the total absence of gases ; a space 
filled with a gas, and under a pressure equal to that of 20 inches mercury as 
measured by the vacuum gauge, would be generally referred to as a fairly good 


steam is equivalent to raising its pressure, so far as its penetrative 
power is concerned ; consequently, the rapidity with which bulky 
articles are disinfected is very much increased, although the tem- 
perature at which they are treated remains unaltered. It thus 
becomes possible to disinfect goods with steam at only 10 lbs. pressure 
as rapidly as with steam at 20 lbs. pressure, when no vacuum is created. 
Both these points are of importance, since of late years the practice has 
become prevalent to treat very bulky things, such as rolls of carpets, 
compressed bales, <fec., and as the amount of work to be done is thus^ 
much increased the disinfecting chamber is commonly packed closely. 
Moreover, the damage done to delicate fabrics, which sometimes lose 
their gloss at 250° F., may be entirely avoided by disinfecting at say 
220° F., without any increase in the time required to secure penetra- 
tion. Altogether, the advantages to be gained by the introduction of 
this inexpensive and simple vacuum apparatus are considerable, and 
great credit is due to the inventors (Mr. J. B. Alliott and Mr. J. M. 
C. Baton). 

Experiments on the Penetrating Power of Steam. — An idea of its 
powers may be gathered from a comparison of the following two trials. 
In p. 296 of Dr. Parson's report it is stated that a cotton rag press- 
packed bale was tested in a Washington-Lyon machine. The dimen- 
sions of the bale were 3 feet fi inches x 3 feet x 2 feet 3 inches, and 
its weight was 5 cwts. At the end of four hours a thermometer at 
its centre registered 258° F., and the increase in weight was 4"8 per 
cent. Experiments were made in 1893 with a similar machine, but 
fitted with the vacuum apparatus, on a press-packed bale of cotton rags 
weighing 5 cwts. 3 qrs. 13 lbs., and measuring 3 feet x 2 feet 4 inches 
X 4 feet 6 inches. The trial was conducted on similar lines, and every 
precaution was taken to prevent the passage of steam down the hole 
through which the thermometer had been admitted by plugging it 
up with a long conical piece of wood larger in diameter than the 
hole itself. The thermometer was so arranged that when the mer- 
cury column reached a height equivalent to 220° F., an electric bell 
was rung outside the chamber. The bell rang precisely forty-five 
minutes after the introduction of the bale to the chamber, and it was 
removed after a final drying by the vacuum and hot air after a further 
period of thirty-three minutes. The whole time taken was seventy- 
eight minutes, and the total increase in weight was less than 2*6 per 
cent. The bale was again submitted to the air-drying for fifteen 
minutes, with the result that the moisture was further reduced by 
30 per cent. 

The accompanying chart shows the mode of working adopted during 
this trial, although it would probably have hastened the process had 




the alterations of pressure and vacuum been more frequent, and it was 
also a mistake to have admitted the steam immediately on obtaining 
the first vacuum, instead of admitting and extracting hot air prior to 
the admission of the steam. The particular trials referred to are not 
such as will have to be frequently repeated in public disinfecting 
stations, but they have been given merely as indicative of the greater 
penetrative and drying powers of jacketted disinfectors when fitted 
with vacuum apparatus. If bedding or clothing has to be treated the 



/ \ 

+220''F reached /n-h. 



/ \ 

centre of Bale..^ \ 


2 10 


• 99 










1 \ 


§ o 




of Trial in Minutes. 




\ / , J , 

, \. 

/ '° 


N^ 40 

50 ^ 





'•S\ / 




Fig. 2. — Chart showing effect of vacuum of apparatus on the penetrative 
power of steam. 

duration of the process is considerably shorter in either form of 
apparatus ; but there still remains the same advantages in favour of 
the machine fitted with the vacuum apparatus. 

English Apparatus — Washington-Lyon's Patent. — In this country 
the machines mostly in use are those made under Washington-Lyon's 
patent. This is largely owing to the far reaching nature of Mr. Lyon's 
specification, on which much litigation has taken place. Generally 
speaking, these machines are made in two forms, square and oval in 

The square form (until recently known as Goddard's patent, made 
by Goddard, Massey, & Warner, of Nottingham) is jacketted all 
round the body, in addition to the two doors. The jacket in this case 
is usually half filled with water, and is used as a boiler. The fire- 
grate is placed immediately under the body of the machine, and the 
firebrick flue (see Figs. 3 and 4) is built to traverse the bottom, and 
thence along other flues, built around the sides of the machine, to the 
chimney. The steam pressure in the jacket (i.e., the boiler) is usually 
limited to 20 lbs., and disinfection is carried on by steam at the same 
and lower pressures. Arrangements are also provided for passing a 
current of hot air through the chamber before and after disinfection. 
The air is heated by passing it through a pipe situated in the furnace 



flue immediately under the disinfector, and thence into the chamber. 
The air may be circulated and extracted from the chamber by means 
of a small exhauster. This apparatus has had a considerable sale 
owing largely to its rectangular form, and there can be little doubt 
that it disinfects adequately, and also that when properly worked there 
should be little or no moisture present in the goods subsequent to 
disinfection. Its apparent first cost is also a factor in its favour, 
although if the cost of the necessary brickwork setting and side flues 
be added to the cost of machine and erection, this advantage is more 

Fig. 3. — Sectional plan of Goddard & Co.'s square form of Washington- Lyon's 
disinfecting chamber. 

apparent than real. Its chief disadvantages are, curiously enough, 
precisely due to those features which are presumably advantageous. 
For instance, the square shape is to some an attraction, whereas it is 
undoubtedly a constructive weakness, and for obvious reasons the 
most suitable section for a steam chamber to stand a considerable 
internal pressure would be circular. Thus this advantage has to be 
paid for in the shape of repairs to leaky joints, insurance, &c., although 
possibly, in certain cases, it may be worth the risk. Again, the use of 
the jacket as the boiler is advantageous inasmuch as less space is 
required ; but, on the other hand, it is an imperfect boiler, which 
cannot be got at properly for cleansing, and is likely to be the cause of 



mishaps, especially at the bottom (which is not readily accessible for 
examination), where the fire impinges directly on the flat plate, and 
gradually burns it away. The presence of jacketted doors is also a 
feature of this machine, although it is doubtful if this additional com- 
plication is necessary when the hot-air apparatus is also supplied. The 
air is heated by the action of the hot gases of the fire, and the only 




Fig 4. — Section through Goddard. & Co.'s square form of Washington-Lyon's 
disinfecting chamber. 

precaution that has to be taken in reference to this point is to warn 
the attendant not to raise too large a fire when using the hot-air 
blast ; for, if this point be not considered, the air may attain a scorch- 
ing temperature, and so damage the contents of the chamber. 

The size of this disinfecting chamber is usually 5 feet x 5 feet x 
6 feet 6 inches internally, although machines of smaller dimensions 
are also made. The following experiment, made on a new machine 
in 1893, gives an idea of the working of this apparatus : — 

The fire was lighted at 10.8 a.m., the water in the jacket being cold, although 
the brickwork was still warm from the previous day's work. At 11.45 a.m. the 


pressure gauge showed 10 lbs. steam pressure, and at 12.0 noon it indicated 194 l^^* 
pressure. The total time occupied for raising steam took one hour fifty-two 
minutes, and about 1 cwt. 1 qr. of coal had been consumed. The door was then 
opened for the admission of clothing. Three minutes were occupied in opening 
and four minutes in closing the door. At 12.10 p.m. the exhauster was set to 
work, and hot air was drawn through the chamber until 12.20 p.m., ten minutes 
in all. The chamber pressure gauge reached 5 lbs. at 12.204 p.m. ; 10 lbs. at 
12.214; 15 lbs. at 12.23; 19 lbs. at 12.27; and 20 lbs. at 12.31. During this 
period, from 12.20 to 12.31 p.m., the jacket pressure fluctuated between 19 and 
20 lbs. At 12.23 p.m. the steam escaped freely from one of the doors which had 
presumably slightly sprung. This happened again subsequently, and had to be 
remedied by tightening the bolts securing the doors. At 12.31 p.m. the addition 
of feed-water to the boiler caused the pressure in the chamber to fall to 17.^ lbs. 
Steam to the chamber was shut ofiF at 12.35 p.m., and the chamber was then 
exhausted. From 12.35i p.m. to 12.44J p.m. hot air was again drawn through the 
chamber, and the door was opened at 12.48 p.m. A certain amount of vapour 
escaped through the door on opening, and some water was found at the bottom of 
the chamber. The goods which were hung up, consisting of overalls, were fairly 
dry and not damaged. A maximum thermometer which had been exposed in 
. the chamber registered 260° F. The total process of steam raising and first 
disinfection occupied two hours and forty minutes, and the total fuel used 
amounted to about 1 cwt. 2 qrs. The time for disinfection only after steam has 
been raised was forty-eight minutes. 

Dr. Whitelegge has been good enough to give the following figures 
relating to some trials made with this apparatus at Leicester in 1889. 
The process was similar to the foregoing, but the total time occupied 
was only twenty-seven minutes, which, apparently, was too little to 
secure penetration. The following are his results.: — 

When removed after disinfection, a horsehair pillow, weighing originally 2 lbs. 
84 0Z8., was increased 1^ ozs. in weight ; it was damp inside but dry on cooling. 
The thermometer in centre indicated 241° F. A flock pillow was increased only 
4 oz., the initial weight being 3 lbs. 84 ozs. This was also damp inside, but dry 
on cooling. The thermometer at centre showed 234° F. 

Three blankets, each folded into 16, piled one above the other on the floor, 
were wet at centre and bottom even on cooling, and the thermometer at centre 
indicated 166° F. Dr. Whitelegge also took the temperature of the chamber at 
different parts when the hot air only was admitted. 

Temperature in hot-air inlet, touching the pipe, was . . . 289° F. 
,, on pillow 1 ft. from inlet, ,, . . . 252° F. 

„ on floor near inlet, ,, . . . 247° F. 

The temperature in chamber due to radiation and convection only, with sknd 
without air current, was as follows : — 
The middle of floor after 15 mins. =239° 
,, roof „ =245° 

The roof near door ,, =239° 

The floor „ „ =241° 

The other form of disinfector generally used in this country is that 
originally known as Washington-Lyon's, and is made by Manlove, 


or after 5 mins. with ejector only 237° F. 


250° F. 


246° F. 


241° F. 



Alliott <fe Co., Ltd., Nottingham. The leading points of diflference 
between this and that made by Goddard & Massey are (1) that the 
boiler, except in the locomotive type, is usually kept distinct and 
separate from the disinfector, and (2) that the section is usually oval 
or round. As made during the past two years, the vacuum apparatus 
invented by Messrs. Alliott & Paton has generally been added, which 
is in itself a distinctive feature, although only of recent introduction. 
In Fig. 5 we show one of this firm's disinfectors of the old type, and 
in Fig. 6 the same fitted with Alliott & Paton's patent vacuum 
apparatus. Fig. 7 shows a portable steam disinfector for purifying 
wearing apparel and bedding in rural sanitary districts. This machine 
has a circular chamber 5 feet long and 2^ feet diameter. The larger 

Fig. 5. — Manlove & Co.'s form of Lyon's disinfector (old type). 

form shown in Fig. 8 has a chamber 7 feet x 4 feet 2 inches x 2 feet 
7 inches, and is fitted with the vacuum apparatus. 

With this class of apparatus, a special boiler is, of course, not 
necessary when steam can otherwise be obtained. The pressure 
in the steam jacket is maintained at 32 lbs. per square inch, but 
the boiler pressure may be anything above this, as steam entering 
the jacket is automatically reduced to the required pressure. In the 
chamber, the steam pressure is maintained (also automatically) at 
22 lbs. In apparatus not fitted with the vacuum arrangement, the 
pressures in jacket and chamber are usually 25 lbs. and 20 lbs. 
respectively. The higher pressure in the first case is found more 
convenient for the double purpose of air heating and extraction. 
This machine when fitted with the vacuum apparatus, may also be 
used as an efficient dry heat disinfector, since hot air is admitted into 
a partial vacuum, which, in other words, is equivalent to working with 
hot air under pressure. The air is heated by passing it through pipes 



surrounded by steam at a constant temperature, and the danger ot 
scorching is thereby obviated. The larger sizes of the machine are 

Fig. 6. — Manlove & Co.'s form of Lyon's disinfector fitted with 
a TacuQm apparatus. 

— -'■T^firH' H'tAiii'Ts. Ji' 

Fig. 7. — Portable steam disinfector (Manlove A Co.). 

usually oval in section, and the smaller sizes round. This is presumably 
with the object of obtaining greater strength and durability, and in 



the oval form the largest articles can be disinfected without great 
expenditure of ground space. The separate boiler admits of ample 
inspection in the ordinary ways, and; if erected at the same time as the 
disinfector, contains, in the most recent designs, arrangements for 
burning the whole of the gases exhausted from the disinfection chamber 
before passing them into the atmosphere. The best mode of working 
this apparatus under ordinary conditions is to admit a current of hot 
air for a few minutes, then obtain a vacuum, and break it with steam 
at 20 lbs. pressure. The steam having done its work of disinfection is 
discharged, a vacuum is again obtained, and a current of hot air 

Fig. 8. — Larger form of portable steam disinfector with vacuum apparatus 
(Manlove & Co.). 

completes the process. In the experiments on a medium size machine, 
details of which are given below, this course was not closely followed, 
as it is the best only when the machine is very full, or the articles 
are bulky. 

Experiments on a Washington-Lyon's Patent Steam Disinfector when 


No. 1. — Charge, 4 mattresses and 4 pillows. 
109 lbs. 1 oz. 

Weight before disinfection = 

11.30 a.m. 

doors close 


11.32 „ 



broken by hot air. 

11.34i „ 

11.364 M 



>> *> 

11.39 „ 

11.41 „ 



„ steam. 

11.43 „ 

11.47 „ 



maintained till 11.50 a.m 

11.62 „ 

11.55 „ 



broken bj hot air. 

11.57 „ 


11.58 a.m. 



broken by hot adr. 

12.0 noon 

12.24 pm- 




12.4i „ 

12.6} „ 



circulation by hot air begun. 

12.9 „ 



i» II 

12.12 „ 

doors opened. 

Total time = 

42 minutes. 


increase in weight = 

1 oz., or 0-05 per cent. 

No. 2. — Two blankets fresh from the laundry wringing machine were next put 
in the disinfector. One blanket contained a large amount of soap, and it was 
noticeable that this one took far longer to dry than the one which was com- 
paratively free from soap. 

Before disinfection, the total weight was 15 J lbs. After 50 minutes one blanket 
was nearly dry, and weighed 3 lbs. 3 ozs. The soapy blanket weighed 4 lbs. 2 ozs., 
and was perceptibly moist. 

The two, therefore, weighed 7 lbs. 5 ozs., or a reduction in weight of 54 
per cent. 

These blankets were then put back into the machine and completely dried, their 
total weight in that condition being about 6| lbs. 

No. 3.— Subsequently, a charge of bedding was treated, consisting of blankets, 
pillows, sheets, &c. 

The total weight before treatment was 29| lbs. 

,, after ,, 28 ,, 

Total time = 35 minutes. 

Diminution in weight = 1 lb. 6 ozs. , or 4^ per cent. 
In none of the foregoing experiments were the articles in any way damaged. 

Dr. Whitelegge also made some experiments on this form of machine 
in 1889, when it was not fitted with the vacuum apparatus. Permis- 
sion has kindly been given to refer to them here, but space does not 
allow of their being dealt with as fully as they deserve : — 

Steam was admitted to the jacket at 10 lbs., but the steam entered the chamber 
at a pressure of 5 lbs. only. A thermometer was placed inside one of the bulky 
articles to be treated, and so connected as to ring an electric bell oatside when 
a temperature of about 220° F. was reached. 

The door was closed at 12.35. 

Steam was turned on at 12.37. 

5 lbs. pressure in chamber at 12.38. 

Bell rang 12.53^ (the bell ceased in 20 seconds upon intermitting the pressure 
inmiediately after this). 

Steam was shut ofif at 12.56. 

Door slightly opened to facilitate drying at 1.0. 

Door opened wide, dry air inside, 1.5. 

(a) Horse-hair pillow (2 lbs. 7i ozs.) weighed 2 lbs. 9i ozs., and was damp in 
centre, but dry on cooling. The electric thermometer at centre rang in 16 
minutes, and corrected reading gave 223° F. 

(6) A flock pillow (3 lbs. 6| ozs.) weighed 3 lbs. 9 ozs. (?), and was damp in 
centre, but dry on cooling. The corrected temperature was 219° F. 


(c) Blue Saxony flannel nf ^ 15 afterwards measured ^m ^ 141 and was 

slightly yellow, but not felted. 

21^ ' 15" 20i 154 

(rf) White, unshriukable flannel -st^ ^ ,-7^ measured afterwards sTi ^Txl* 

This also was slightly yellow, but was not felted. 

(e) Six sami)les of coloured silk, pleated, were unchanged, except that the dark 
green became wet and black. These had been placed near the door. 

(/) Thick book (Churchill's Directory) on floor was cool inside. Thermometer 
placed uncovered in other parts of machine showed temperatures varying from 
228° F. to 234° F. 

A further experiment was then made on following lines : — 

Door was shut at 1.21 p.m. 

Steam admitted 1.22. 

Full steam pressure attained in chamber (5 lbs.) 1.23. 

Pressure was intermitted at 1.31. 

Bell rang at 1.35. 

(o) Two blankets, each folded into sixteen layers, laid one above the other on 
the wooden floor, were damp on removal, and dry on cooling. 

The electric thermometer at centre — i.e., with sixteen layers of cover — showed a 
corrected temperature of 228° F. The bell rang in 12 minutes. 

Another experiment was made with low-pressure steam, with ^ lb. pressure in 
both chamber and jacket. 

Door was closed at 2.17. 

Steam at ^ lb. pressure in chamber at 2.20. 

Bell rang at 2.37. 

(a) Two blankets arranged as before were wet, but became immediately dry on 
shaking. The bell rang in 17 minutes, and the thermometer showed a tempera- 
ture of 214° F. 

(6) Horse-hair pillow came out steaming, and thermometer indicated 216* F. 
at centre. 

(c) A flock pillow came out steaming, and the thermometer at centre indicated 
213° F. 

It is noteworthy in Dr. Whitelegge's experiments, that when steam 
at 5 lbs. pressure was used the thermometer at centre of blankets 
registered 228° F. in twelve minutes, and that when steam at J lb. 
pressure was used the thermometer, under apparently identical 
conditions, indicated only 214° F. after seventeen minutes, and also in 
the latter case pillows were taken out steaming. Although the types 
of disinfecting apparatus described are not absolutely the only ones used 
in this country, probably more than three-fourths of those erected in 
the past ten years have been of these types. 


1. Austria — Thursfield's Apparatus. — On the Continent, several 
foreign designs have been extensively used, ^and some of these are 



occasionally to be met with in this country. Fig. 9 represents a 
portable form of apparatus used to some extent in Austria, and 

Fig. 9. — Thursfield's portable disinfector (large). 

designed by Mr. Thursfield, of Vienna. It is, in the modern patterns, 
usually circular in section and jacketted ; the jacket is partially filled 
with water, and acts as a boiler 
with the fire underneath. The 
boiler is open to the atmosphere, 
and, therefore, when steam is ad- 
mitted to the chamber it is only 
at 212° F. A continuous current 
of steam is kept passing through 
the chamber, and as the latter is 
jacketted by the boiler casing, con- 
densation is largely minimised, and 
the inventor states that clothing 
removed after treatment is only 
slightly damp. After each disin- 
fection the boiler is partially refilled 
with cold water, and, consequently, 
ebullition ceases for a time. It is 
stated that the boiler contains 20 
gallons of water, and can generate 
steam in twenty-five minutes from water at 50° F.; the total time 
required for one disinfection is said to be sixty-eight minutes. 

Fig. 10. — Thurslield's portable 
disinfector (small). 


Maximum thermometers placed inside diflferent articles registered 
218° F. The consumption of fuel during the above trial was said 
to have been only 7 lbs. wood arid 19 lbs. of coal. A smaller form 
of the Thursfield disinfector is shown in Fig. 10. 

2. France — The Equifex Stove. — A common type of apparatus in 
France is that made by Geneste, Herscher & Co., of Paris. This 
machine is externally not unlike those of Washington-Lyon, although 
its construction is materially different, inasmuch as there exists no 
steam jacket, and only comparatively low-pressure steam is employed. 
It is made in several sizes and types, which may be briefly described 
as follows : — 

(1) It is a fixed machine working with steam at from 7 lbs. to 
10 lbs. per square inch ; consequently the maximum temperature to 
which the infected articles are exposed is from 230° F. to 240° F. 
The large size is commonly 6 ft. diameter and 13 ft. 6 in. long, 
inside of which are two sets of steam-pipe coils. Each set consists 
of eleven pipes running the whole length of the machine, one being 
placed at the top, the other at the bottom of the chamber. These 
coils are so arranged for drying purposes, and to prevent condensa- 
tion. Arrangements are made to enable the air to escape through 
a pipe at the bottom of the disinfector pending the admission of steam, 
with which the disinfecting process is commenced. When the pressure 
has reached 7 lbs. to 10 lbs., the steam is exhausted and a fresh quan- 
tity admitted. In this way the inventors claim that sufficient pene- 
tration is secured without the aid of steam at a higher pressure, and 
also that it is only necessary that steam at 10 lbs. be actually in 
contact with the goods for not less than fifteen to seventeen minutes, 
in addition to the time taken in filling and exhausting the chamber, 
which should be done not less than three times during the operation. 
Before the goods are taken out it is recommended that they be left 
in the closed machine for some time to dry, although the precise time 
taken by this process is not clear. 

(2) Messrs. Geneste, Herscher & Co. also make a type to work at 
from 2 lbs. to o lbs. pressure with current steam. In this machine 
the temperature to which the goods are exposed does not exceed 
217° F. to 222° F. The inventors make a point of bringing the 
steam into the chamber at the top and extracting it at the bottom, 
and say that the air in the chamber is thereby effectively driven 
from the chamber. The steam pressure in the case of this machine 
is too low to make the relaxation and renewal of pressure of 
any benefit to penetration. The steam is only nominally "current" 
because the outlet is governed by a modified form of reducing valve. 
A feature of the apparatus is that the two doors are so interlocked 




that it is impossible to have the two doors open at the same time, but 
otherwise the arrangements of this type are similar to those in the 
other. In Fig. 11 we give an illustration of an Equifex horizontal 
stove working with confined steam. 

The disinfecting chamber, A, is a wrought-iron cylinder without jacket or other 
means of superheating the steam, but lagged with wood and coated with a non- 
conducting composition. The stove usually passes through a partition, B, to 
separate the infected objects from the disinfected. The doors, C, D, are fitted with 
an arrangement making it impossible for both to open at the same time, and are 
secured by nuts, E, locking into solid steel recesses, F, on the door. A row 
of steam tubes runs longitudinally inside the stove for warming the stove 
before and during disinfections, and for heating the air which is used in the 
subsequent drying of thick objects. The steam is led to the stove by a pipe, G, 
from the boiler, and, after traversing a separator, H, passes through the reducing 
valves, T, K, and safetj' valves, L, M, to the stove and tubes respectively. When the 
desired pressure is reached in the tubes, as shown by the gauge, N, steam begins 
to escape through the safety valve, M, and the attendant then regulates the pres- 
sure by the reducing valve, K. The stove, having thus been warmed, is charged 
with the objects, 0, to be disinfected, which are loaded in the ordinary way on to 
a wheeled carriage, P, running on rails within the stove, and on hinged rails, Q, 
outside. The door is then closed, and locked with the safety nuts, E, and the 
valve, I, is opened, allowing steam to pass through the safety valve, L, into the 
body of the stove. The steam enters the stove through an internal sparge-pipe 
fitted longitudinally inside it towards the top, and furnished throughout its length 
with a screen to assist in the thorough projection of the steam to all parts of the 
stove. The steam is at first allowed to escape through the air discharge pipe, R, 
and carries with it the air from the stove. The discharge pipe, R, is fitted with 
a thermometer, S. When the air is ejected, the mercury will rapidly rise to 195° 
to 205° F., at which point the valve, T, controlling the pipe, R, is closed. The 
steam continues to enter the stove through the valve, I, till it reaches a pressure 
of 10 lbs. per square inch, as marked on the gauge, U, when it escapes through 
the safety valve, L, until the attendant has regulated the pressure by the 
reducing valve, I. A film of water is formed throughout the pores of the 
object under a pressure just sufficient to keep it from evaporating. Advantage 
is taken of this fact to get rid of the air secreted originally in the pores of 
the object by shutting off' steam occasionally (say every five minutes) by 
means of the valve, I, and opening the sluice valve, V. The sudden reduction of 
pressure so eff'ected causes a sudden re-evaporation of the condensed steam in the 
objects ; so what was water in the pores expands into steam of some sixteen 
hundred times its volume, sweeping out before it the air from the pores. To 
assist this process the stove is fitted with a pneumatic exhaust, operated without 
any moving parts by the steam pressure. For this purpose a jet of steam is 
allowed, by means of the valve, W, to pass up an aspirator or ejector fitted in the 
steam discharge pipe, X, so automatically sucking out both the steam and the air 
ejected from the jwres, and producing a partial vacuum under which the vaporisa- 
tion of the steam and the ejection of the air is completed. With objects of 
ordinary thickness disinfection is complete in fifteen to seventeen minutes. 
Steam is then let off" as before ; and on the door being opened, all objects such 
as blankets, clothes, &c., are taken out and shaken, when they will be found to 
be perfectly dry. Mattresses and thicker objects are replaced in the stove for 
five minutes for the aspirator to withdraw the steam. 



3. Denmark — Reek's Apparatus. — In Denmark, Mr. A. B. Reck, of 
Copenhagen, has designed an apparatus which contains some features of 
novelty j but, like most of the foreign apparatus, it does not aim at so 
much as those of English design, and he is content to disinfect " in such 
a manner that things would be spoiled by steam as little as possible." 
The inventor attributes the presence of moisture in goods almost 
entirely to the inrush of cold in the presence of vapour, and his 
improvements are directed towards diminishing this evil. After the 
goods have been steamed (at about 1^ lbs. pressure), a spray of water 
is injected at the top of the chamber in such a way as not to impinge 
on the clothes, and, simultaneously, a large air valve is opened at the 

f° i« i» 

1 ^ 1* 

i— 1« P 1^ ^,„h 

Fig. 12. — Reek's steam disinfector (transverse section). 

bottom. It is claimed that the steam contained in the chamber rises 
to the top, is condensed by the cold water spray, and the momentary 
partial vacuum so produced is re-occupied by air rushing in at the 
bottom of the chamber. In this way the whole of the vapour is con- 
densed and carried away with the water, and when the chamber door 
is opened cold air only is present. The main difficulty of condensation 
on the clothes during disinfection due to radiation, and their own low 



temperature, is not dealt with in any way, either by steam jacketting 
or preliminary heating by hot air. 

In Figs. 12 and 13 we show two sectional views of Reek's apparatus. 
Dr. Reid has lately tested this form of disinfector, and has reported 
favourably upon it to the Stafford County Council. 

4. Germany — Schimmers and Budenberg's Apparatus. — A disinfecting 
apparatus largely used in Germany is that made by Oscar Schimmel, 


Fig. 13. — Reek's steam disinfector (longitudinal section). 

of Chemnitz. There is nothing very striking in its design, and pro- 
bably the explanation of its extensive use may be found in the fact 
that it was one of the first to be placed on the market. The claims 
made are, broadly speaking, three. First the clothes are warmed by 
hot air to a temperature of 60° C; secondly, they are steamed by 
current steam at atmospheric pressure ; and lastly, they are partially 
dried, and aired again by warm air. No pretence is made that the 
articles come out perfectly dry, or that the process is a rapid one, but 
it is justifiably claimed that articles which are not too bulky are 
disinfected, and also that the first cost of the apparatus is moderate. 



Fig. 14 shows a small vertical type with steam-generating apparatus 
and fire beneath. Steam rises round the chamber in which the clothes 
are situated, and enters at the top and leaves at the bottom, while 
condensed steam returns to the boiling apparatus. Great care would 
have to be exercised to see that water never ran short in the domed 
bottom, for it is very small in quantity, and would need frequent 

Fig. 14. — Schimmel's vertical steam dlsinfector. 

replenishing by hand through the funnel. When a charge has been 
disinfected, the fire has to be drawn in order that steam may be pre- 
vented from passing into the chamber. To obtain air circulation, a 
small door is removed in the crown, and, the exhaust pipe being also 
open, a certain air circulation is obtained owing to the heat retained in 
the clothing and walls of the chamber. 

In the larger size shown in Fig. 15, which is oval in section, more 
elaborate arrangements are provided for air heating, «kc., and steam 
has to be obtained from a separate boiler. The gilled pipes at the 
bottom are filled with steam at boiler pressure, and thus to some 
extent they check condensation in the chamber when steam at atmo- 
spheric pressure is admitted. Air circulation is again obtained entirely 
by the crude method of opening a small door at the bottom of the 




chamber close to the gill pipes, and allowing it to rise and escape at 
the top by the exhaust pipe. Machines of this type have been at 
work in Berlin for about ten years. In the larger apparatus it is 
usual to admit current steam to the chamber at about 1^ lbs. pressure. 
It is necessary when working the apparatus, first to warm it up by 
hot air for not less than thirty minutes, and then, after putting in the 
goods, to again warm them for thirty minutes or thereabouts. Steam- 
ing is said to take about thirty minutes (although this must surely 
depend largely on the articles being treated), and the final drying 
occupies another fifteen minutes. The whole process, including load- 
ing and unloading the truck, should, therefore, mean an expenditure 
of time amounting to nearly two hours ; and, even when taken out, 
the articles are supposed to undergo a further process in an ordinary 
drying closet. 

Fig. 16. — Budeuberg's steam disinfectiug apparatus. 

The general arrangements of Schimmel and Geneste Herscher's 
apparatus all bear a considerable resemblance the one to the other, 
and it is difficult to see how the actual work done by the various 
designs should be very different in result. It is, therefore, to the 
credit of Herr Oscar Schimmel that he should almost alone admit the 
weaknesses of his apparatus, and at the same time give financial 
reasons as a valid excuse. The apparatus of W. Budenberg, of 
Dortmund, works at about 3 lbs. pressure, and is very similar to that 


of Geneste Herscher's (Fig. 16). It has been carefully studied by 
Dr. Hahn.* 

United States. — In the United States the apparatus of Geo. V. 
M'Lautlin & Co., of Boston, is used to some extent, as is also that of 
Washington-Lyons. M'Lautlin's machine bears a very close resem- 
blance to Geneste Herscher's apparatus, the only appreciable difference 
being that it is built in an apparently more substantial manner to 
enable it to work with steam at a pressure exceeding 10 lbs. Generally 
speaking, disinfecting apparatus on the Continent is built with rather 
a different object in view to that which obtains in this country. It is 
not regarded as essential for the clothes to come out absolutely dry ; 
and if they have to be dried by some other means after treatment, 
that is not considered prejudicial to the machine. 

Time, also, is not valued to the same extent' as in this country, 
whereas first cost is a matter of the greatest importance. As a 
consequence, a cheaper machine is produced, which disinfects at the 
expense of wetting the goods after a more prolonged exposure. These 
conditions do not obtain generally in this country, for frequently, 
owing largely to recent regulations, the whole of the clothing and 
bedding of a family have to be disinfected and returned ready for use 
within one or two hours, whilst the family is housed at the public 
expense pending the chemical disinfection of their own room. The 
public sentiment is also in favour of purchasing things of the most 
durable nature, in spite of the fact that their first cost greater. 
Lastly, the use of low-pressure steam is not largely favoured, because 
very bulky articles, such as bales, cannot be disinfected in machines 
using it ; whereas, high-pressure machines can not only deal with the 
bulkiest articles, but can always, if desirable, be used with low-pressure 
steam with equal efficiency. 

It is probably for these reasons that low-pressure disinfectors have 
been tried, and very largely abandoned at home. 


Plan of a Disinfector House. — The main point which has not yet 
been dealt with in this chapter is the arrangement of building and 
appurtenances requisite for a public installation. Owing to the 
courtesy of Mr. Rowland Plumbe, F.R.I.B.A., of London, the 
drawings of the disinfector house and incinerator at present being 
erected for the Vestry of St. Mary's, Newington, are shown in the 
plate opposite. The particular arrangement is not one which must 
be followed in every instance, for each case has to be treated on its 

* DetUsch. Medic. Wochemch., 1890, No. 12. 




merits, and this building has had to be adapted to its environments. 
It is, however, a fairly representative installation, arranged with 
considerable care, and is complete, with the exception that the plan 
does not show the sheds for the infected and disinfected vans or 
hand carts, which have been subsequently erected. 

The main feature of a disinfector house is that there shall be two 
rooms ; one permanently kept for infected goods, and the other for 
disinfected goods. The machine is built in the wall dividing the two 
rooms, and is fitted with two doors, one door opening into each room. 
These doors should never be open at the same time, and there should 
be no direct inter-communication whatever. Two men should be 
provided to work the apparatus, one of whom should have his duties 
confined to the infected side, and the other to the disinfected side of 
the apparatus. Generally, one man only is told off to look after the 

Fig. 17. — Dr. Sergeant's incinerator. 

infected side, where the boiler and things that require attention are 
placed, and he signals or shouts to some man engaged on other work 
when goods have to be moved from the machine into the disinfected 
room. The incinerator is no essential part of the disinfection, but is, 
nevertheless, sometimes put on the same site for the purpose of 
destroying by fire bedding or clothing that is not worth disinfecting. 
For instance, it sometimes happens that the mattress of cholera 
patients are purposely of the commonest description, and only fit to 
burn. They can only be burned in very carefully constructed furnaces, 
fitted with a secondary fire to destroy the objectionable products of 
combustion ; otherwise, the process might become a nuisance and 
danger to the neighbours. They are also useful for getting rid of 
condemned meat, offal, excreta, &c. A figure of Dr. Sergeant's 
incinerator, which is the one adopted at Newington, is shown in Fig. 
17. At Newington, the same chimney is used for both the disinfector 






boiler and incinerator, but otherwise the two departments are kept 
distinct. The minor points to be attended to in the building for a 
disinfector require also some care. The floor should be of some smooth, 
hard material, such as cement, laid with a fall towards a drain ; and 
arrangements should be provided for swilling out the two rooms very 
thoroughly by fixing a small hose to taps in either room. All internal 
angles should be rounded, so as to permit of ready cleansing ; and 
slate and iron should be used where possible in preference to wood for 
the racks and fittings. Good washing accommodation and w.c. should 
also be provided for the attendant, and special overalls should be given 
him for wear whenever at work in the building. These overalls should 
be disinfected before allowing them to go to the laundry. Considerable 
attention should be paid to the ventilation of both rooms, as in summer 
the radiated heat from the boiler and machine is apt to be oppressive. 
The lighting should also be ample and well diffused, for this encourages 

United States. — For the Marine Hospital Service of the U.S. 
Government at the modern stations plant has been provided for 
disinfecting by heat, by fumes, and by chemicals. The arrangements 
have been described by W. H. Francis of Philadelphia,* and are 
shown in Figs. 18 and 19. The disinfectors are two rectangular 
steam -jacketted chambers 16 feet long, with steam-tight doors opening 
at each end. The chambers are constructed of an inner and outer 
steel shell, 2^ inches apart, cast-iron end frames, intermediate truss 
bands, and of screw stay-bolt construction. The doors have concave 
steel plates riveted to cast angle frames fitted with heavy rubber 
gaskets, they are handled by convenient cranes, and drawn tight by 
drop-gorged steel eye-bolts, swinging in and out of slots in the door 
frames. The chambers, therefore, act as drying ovens, the articles 
being heated before the admission of the steam, and thoroughly dried 
after the steam has been exhausted. A vacuum of 15-20 inches can 
be produced in the chamber before the admission of the steam, and 
any pressures up to 15 lbs. (250° F.) can be obtained. 

For fumigating at this station, 3 lbs. of sulphur per 1,000 cubic feet 
of air space are employed, and for disinfecting with liquids, mercuric 
chloride (1 : 1,000), carbolic acid, and chloride of lime, are at present 

* Proc. Am. Soc. Mech. Engineers, vol. xv. 




The halogens — Chlorine, chlorides, hypochlorites, chlorates — Bromine, bromides — 
Iodine, iodine trichloride, iodic and periodic acids and periodates — Fumigation 
— Fluorine, fluorides, silicofluorides — Chloroform, bromoform, iodoform — 
Organic haloid compounds. 


Chlorine. — About the year 1800, Guy ton de Morveau in France, and 
Cruikshank in England, proposed the use of chlorine as a disinfectant. 
Cruikshank suggested the following method of procedure : — *' 2 pts. 
common salt, and 1 pt. powdered manganese, with 1 pt. water and 
^ pt. sulphuric acid gradually added, is sufficient for five or six beds." 

A similar method of generating chlorine is to gently warm one part 
of manganese dioxide in a granular form with four parts of concentrated 
hydrochloric acid (5 grms. MnOg and 20 grras. HCl give 1 litre of 01; 
I oz. of MnO^ is abundance for a large room).* Letheby recommended 
one teaspoonful of powdered manganese and half a cupful of strong 
crude hydrochloric acid, mixed by degrees by stirring in a saucer set 
on a hot brick. 

It should be remembered that the crude acid contains arsenic, 
which would be evolved as the intensely poisonous arsenious chloride ; 
hence, at a little additional expense, pure acid only should be employed. 

Each of these methods requires heat, which presents great difficulties 
in application. Usually, therefore, the chlorine is evolved from chloride 
of lime by the action of moderately diluted sulphuric or hydrochloric 
acid. It has been stated t that 1 part bleaching powder with 2 parts 
of sulphuric acid of specific gravity 1*53, and enough water to cover 
the powder, evolved three times as much chlorine as when hydro- 
chloric is used. This may be due to the heat generated by the 
sulphuric acid, as the amounts yielded are theoretically the same, 
as the following equations show : — 

CaCljO + H2SO4 = CaS04 + HjO + Clj. 
CaCljO + 2HC1 = CaCl, + HjO + Clg. 

If the insoluble and, therefore, solid sulphate of lime keeps back less 
chlorine than does the deliquescent calcium chloride, the difference in 
the yield might be explained. 

* Reichardt, Deain/ectionsmiltel, p. 65. i Lancet, 1888, p. 110. 


Dr. Mehlhausen * of Berlin used 600 grammes of bichromate of 
potash and 3 kilos, of pure hydrocWoric acid, of specific gravity 1"16, 
for generating chlorine. These weights yield on warming 130 "6 litres 
(405 grms.) of chlorine. He traced a somewhat greater activity to the 
gas than when prepared by the ordinary processes ; this may, perhaps, 
be due to some chromyl chloride (CrOgOlg) evolved in addition. The 
cost of this method prevents it from being generally employed. 

Chlorine has three possible modes of action : — 

1. It may replace hydrogen in the organic substances, forming 
innocuous compounds and poisoning the bacteria. Such action would 
be slow, would scarcely occur at all except in sunlight, but yet would 
be the only possible action on dry matter. It may account for the 
antiseptic action of chlorine, as distinguished from its disinfecting 
power ; the latter has been questioned, but the experiments of Baxter 
and Sternberg on dried vaccine lymph seem to be conclusive. 

2. The offensive gases of putrefaction are decomposed by chlorine ; 
sulphuretted hydrogen, which is always present, being resolved into 
sulphur and hydrochloric acid — 

HgS + CI2 := 2HC1 + S. 
Phosphoretted hydrogen from animal matter would be also decom- 
posed. Ammonia (and compound ammonias) would give first of all 
ammonium chloride and nitrogen — 

8NH3 + 3CI2 = 6NH4CI + N2, 
hence the copious white fumes frequently noticed when a chlorine 
mixture is thrown into a dung pit. More chlorine decomposes the 
ammonium chloride first formed ; when this takes place there is 
always a formation of intensely acrid vapours which attack the eyes, 
owing, no doubt, to the production of chloride of nitrogen. Hydro- 
carbons would in most cases be little affected by chlorine, but they, as 
a rule, are not so offensive as the other gases mentioned. 

3. The common and most important action of chlorine is as an 

oxidising agent. In the presence of water, more especially in light, 

it combines with hydrogen to form hydrochloric acid, and liberates 

oxygen — 

HjO + CI2 = 2HC1 + O. 

The oxygen so formed is far more active than atmospheric oxygen, 
and is in a condition to burn up the putrescent matters and kill the 
organisms which accompany the putrefaction. But there are several 
conditions indispensable to thorough disinfection, and amongst these 
(a) tJie presence of moisture is absolutely essential when chlorine fumi- 
gation is resorted to. 

* Bericht der Cholera Commission, 1879, vol. vi., p. 335. 


(6) Qtuintity. — Baxter says that the disinfecting action of chlorine 
and of potassium permanganate depend much more upon the nature 
of the liquid than upon the specific organism present. Kuhn, 
Bucholtz, and Haberkorn have confirmed this view. For example, in 
a liquid like urine, which requires large quantities of chlorine, before 
the liquid be deodorised, the action on germs does not begin before 
the chlorine is in excess, and it must be maintained in excess until 
the last germ is destroyed, otherwise the fermentation will recom- 
mence. But if the action has been completed, germs that may 
afterwards enter from the atmosphere find it an unsuitable medium 
for growth. From this it follows that the smell of chlorine must be 
perceptible and persistent for some time, or no good result will have 
been obtained. Excess of chlorine may be chemically tested for by a 
paper dipped in a solution of iodide of potassium and starch paste, 
which is turned blue by free chlorine, or the bleaching of litmus paper 
may be used as an indication. 

Baxter in his experiments mixed chlorine with vaccine lymph, and 
found that its activity was not destroyed till the liquid had become 
acid from the presence of free hydrochloric acid. Most putrefactive 
organisms thrive best in alkaline solution ; hence the antiseptic power 
of all free acids in varying degrees. 

To kill pure vaccine, Baxter found the minimum proportion of 
chlorine to be 0*2 per cent, {i.e., soda chlorinata solution, B.P. 1 in 10 : 
chloride of lime, 1 in 100, both acidified). Hofmann * gives 0'15 per 
cent, as sufficient for septic virus. 

(c) Time. — The vitality of the organisms considerably influence the 
length of time required for sterilisation. Sternberg f found that 
1 per cent, of chlorine in air in six hours made dry vaccine inert. 
This is a very large quantity, for a room of 50 cubic metres would 
require at this rate 5 kilos, of bleaching powder, even if all the 
chlorine were evolved, which is generally impossible. Baxter states J 
that air saturated with chlorine by standing over the aqueous solution 
took thirty minutes to sterilise needles charged with dry vaccine. 

These are impossible conditions in practice. Living organisms 
themselves contain 90 to 95 per cent, of water, hence the disinfectant 
entering them would be greatly diluted. Moreover, their envelopes 
are often tough and resisting, especially those of germs. Therefore, 
more time must be given. 

Fischer and Proskauer,§ from laboratory experiments on spores of 

* Viertdjakrsschrift fiir gerichtliche Medicin, April, 1878. 
f Bulletin of the U.S. Board of Health, Washington, 1881. 
t Report of Med. Off. of Privy Council on Dininfectanta, 1875. 
§ Mitt, aus d. Kaiserl. Oesundheitsamte, Berlin, 1884. 


anthrax and various bacteria, conclude that for air fumigation at 
least 0"54 per cent, of chlorine must be present, and consider it more 
efficacious than sulphurous acid. "The experiments of Jalan de la 
Croix,* on the putrefying bacteria of beef tea, give a surprisingly 
favourable account of the power of chlorine among the agents which 
are fatal to low organisms, and place it next to corrosive sublimate as 
an " anti virulent." 

The substances tried, arranged nearly in their order of efficiency as 
determined by him, were as follows : — Mercuric chloride, chlorine, 
chloride of lime, sulphurous acid, bromine, sulphuric acid, iodine, 
aluminium acetate, mustard oil, benzoic acid, sodium salicylate, 
potassium permanganate, phenol, chloroform, borax, alcohol, oil of 
eucalyptus, potassium chlorate. The methods used were first that of 
Bucholtz, then those of Salkowski, Wernicke, and Wernitz, and other 
specially devised " bacterioscopic " processes.! He concluded that 
" besides chlorine, bromine, and iodine, we have only sublimate and 
osmic acid that will kill the bacteria of splenic fever within twenty- 
four hours." 

Given the above time, he states as to quantity that " in beef tea 
all growth is stopped by ] in 30,208 — i.e., 1 gramme of chlorine in 
30 litres (chloride of lime, 1 in 11,135 has the same efiect) ; 1 in 
22,768 kills bacteria in full" growth, and prevents their spontaneous 
development in cooked beef tea exposed freely to air ; tliat of 1 in 
15,606 in raw beef tea. Chloride of lime is required in stronger doses, 
of 1 in 3,700 in cooked, and, contrary to what one would expect, 
1 in 286 in raw beef tea." 

To destroy the germs it requires yet larger amounts, varying 
between 1 in 431 and 1 in 4,911 for chlorine, and 1 in 100 to 1 in 
500 for chloride of lime. 

Vallin J throws some doubt on the above researches, and asserts 
that the antivirulent action of chlorine is relatively restricted, and is 
notably inferior to what would be presumed by the above figures. 

Dr. Mehlhausen§ made a number of experiments, of which the 
following is an abstract : — 

I. In a room of 37 cubic metres with door and window sealed, he 
placed a number of insects in gauze enclosures, and two vessels of 
water teeming with vibrios, rotifers, and infusoria. An earthen pot 
containing 740 grammes (20 grammes per cubic metre) of bleaching 

* Arch, far experiment. Pathologic, 1881. 

t Wernitz, Grundrias der Desinfectionslehre, pp. 166 to 178, and Virchow's 
Archiv., voL Ixxviii., pp. 53 to 60. 

t Traits des Disinfectants, 1882, p. 118. 

%Bericht der Cholera Commission, 1879, vi., p. 335. 


powder with a little water, to which he added 1,100 grammes of hydro- 
chloric acid, was also introduced and the door sealed. After nine 
hours the room was opened and ventilated. The animals were all 
living ; the flies only were insensible, but recovered on the next day. 
The water in the vessels, originally neutral, had become acid, and 
gave with nitrate of silver a copious precipitate of chloride. All the 
bacteria were dead. The 740 grammes of chloride of lime had given 
59*7 litres of chlorine — i.e., 1-613 litre per cubic metre, or 01613 per 
cent, in the air (about the amount mentioned by Hofmann, as above 
given), whilst some had been undoubtedly wasted by non-evolution 
and by leakage. 

II. With the same conditions as before, but with double the amount 
of chlorine. The vessel contained fermenting urine. In eight hours 
there was much residual chlorine. Most of the higher organisms were 
killed ; the urine had become acid, but the bacteria and spirilla were 
still moving. 

III. Equal parts of common salt and manganese dioxide, with 
2 parts of sulphuric acid and 1 part of water, were warmed together, 
whilst putrid urine and dysenteric stools in wide flat dishes were 
exposed for twenty hours to the gas. On opening, only a feeble odour 
of chlorine was noticed, as it was masked by the effluvia from the 
stools and urine. Some of the organisms were only benumbed, and 
recovered their activity in fresh air. The liquids were very acid, and 
had not entirely lost their fetid odour. 

IV. In another room of 48 cubic metres a glass balloon was placed 
containing 600 grammes of bichromate of potash and 3 kilos, of hydro- 
chloric acid of specific gravity 1-16 ; by warming, 405 grammes of 
chlorine were evolved, equal to 2*7 litres per cubic metre, or 0-27 per 
cent. Under these conditions all the organisms were killed, but the 
time required was not stated. The process is, however, long, expen- 
sive, and somewhat diflicult, costing about 4 centimes per cubic metre, 
or about Is. 6d. for disinfecting a room 11 feet square. 

Vallin points out that fumigations with chlorine are of little advan- 
tage, and are decidedly inferior to those with sulphurous acid. The 
disengagement of chlorine is incomplete, unless stirred and heated 
constantly, which is almost impossible in ordinary practice. The 
facility of '* sulphuring " is, on the other hand, of the greatest value, 
and the expense is about four or five times less.* 

Jeannel t noticed that chlorine seemed to have only a temporary 
action on certain vibrios, as he was able by means of ammonia to 
restore them to activity after they had been subjected to the influence 
of chlorine for a long period. 

* See Sulphurous acid, later. i Union Midicale, Sept. 28, 1871» 


The experiments of Sternberg* concerning the action of chlorine 
on infusoria and micro-organisms show that the resistance of the latter 
is considerable. In an experimental room of 10 litres capacity, he 
placed 28 grammes of chloride of lime. It was an hour and a half 
before the movements of the bacteria contained in a drop of putrid 
meat infusion ceased, although the watch glass holding the liquid was 
directly exposed to the gas. (If he did not acidify, the only chlorine 
evolved would be that liberated by the small quantity of carbonic acid 
in the air present — namely, about 0*071 per cent. — which is too small 
a proportion, if we take Hofmann's minimum of 0'16 per cent., or 
Baxter's 0*2 per cent, be admitted.! But the total amount would still 
be immense if it could be absorbed by the drop of fluid, as it would 
reach 7 grammes of chlorine in the 10 litres of air.) Sternberg did not 
consider the movements definitely destroyed until after an hour's 
exposure to fresh air, they had not reappeared. 

Dr. Cash | subsequently studied the action of chlorine, and en- 
deavoured to determine the comparative value of the halogens and of 
sulphurous acid in destroying the virus of anthrax and tubercle ; he 
concluded that the halogens do not present any great difierences when 
employed in solutions, the strengths of which are proportional to their 
atomic weights, though chlorine was the least active and iodine the 
most. This would oblige us to use 127 parts of iodine for 80 of 
bromine and 35*4 of chlorine. He found that when employed in 
dilute solutions they did not disinfect. (That is, below Baxter's limit 
of 0*2 per cent.) He prefers sulphurous acid if the disinfecting agent 
be employed as a gas, but considers it better to employ a solution of 
the gas if possible.§ 

(d) Contact. — Intimate contact between the gas and the centre of 
infection must be assured. If large masses of putrescible matter like 
faeces are present, chlorine gas fails in its action, and must be supple- 
mented by the addition of metallic salts, &c. For if all easily de- 
composable organic matter be not destroyed, a recommencement of 
putre&ction is not prevented. || 

Klein II used chlorine fumigations in stables for disinfection from 
swine plague with success. 

When in great mass — e.g., dung and straw in typhus — care must be 
taken not to give a false security by illusory means. Probably in many 
cases it is better to rely on purification being accomplished naturally 

• Bulletin of National Board of Health, Washington, July 23, 1881. 

t See later, under Chloride of lime. 

XPharm. Joum., 1S87, p. 485 ; L. O. B. Sixteenth Annual Report. 

% See later, Sulphurous Acid. || Reicbardt, Desin/ectionamittel, p. 57> 

IT L. O. B. Thirteenth Annual Report. 


by air and moisture than run the risk of natural decomposition being 
retarded by the employment of inefficient quantities of antiseptics. 
It must be remembered that manure that has been treated with 
chlorine or chloride of lime loses all its agricultural value on account 
of the destruction of its ammonium salts. On the other hand, if 
chloride of lime is sprinkled over faecal matter before removal, it 
destroys any offensive gases that may be evolved. 

It cannot be too strongly emphasised that air cannot be disinfected 
and still remain fit to breathe. Wernitz * condemns all fumigations 
as useless, classing all methods as "illusory specifics," since " we 
require a body which shall come in intimate contact with atmospheric 
dust, and act for a long time on it." Vallin says " disinfection of air 
is useless and gives a deceitful security. To make a strong odour of 
phenol, or put a basin of chlorine in a corner, is, with regard to de- 
struction of virus, an operation quite futile, as the virulent particles in 
air are probably protected by an envelope of dried albuminous matter." 

Chloride of Lime and Hypochlorites. — By treating the alkalies and 
alkaline earths in solution with chlorine in the cold, mixtures of 
chloride and hypochlorite are formed which have been long known as 
useful disinfectants. 

Liquor sodse chlorinatse, B.P., chlorinated soda, or " Eau de 
Labarraque " has a strength of 2^ per cent, of available chlorine. It 
is used in surgery diluted with 10 parts of water (equal to Baxter's 
effective strength of 0*2 per cent. CI) as an antiseptic lotion, and is 
refreshing and non-irritant. By its decomposition it produces a small 
quantity of common salt. It has also been employed as a mouth wash. 

"Eau de Javelle," introduced by Percy in 1793, is similarly made, 
but with potash instead of soda, and is said to keep longer than the 
soda compound. The orders of the French Prefecture recommended 
1 part of Eau de Javelle of 18° Baume to 100 parts of water for 
flushing closets and washing walls, &c. It has the advantage over 
" chloride of lime " that it does not leave behind a deliquescent body 
like calcium chloride. It acts similarly to chlorine. 

" Chloride of lime" or bleaching powder, obtained by passing chlorine 
over moist slaked lime, has the advantage of being a dry powder, which 
is more easy of transport and keeps better than the soda and potash 
preparations. It is a mixed chloride and hypochlorite of the formula 
CaCljO, and breaks up into chloride and hypochlorite on solution in 
water. The latter is strongly alkaline, and is acted on by the carbonic 
acid of the air giving carbonate of lime and hypochlorous acid. 

2CaCl,0 = CaClj + Ca(C10)j 
Ca{C10)j + COj + HjO = CaCOa + 2HC10 

♦ Desin/ectiontlehre, 1882. 


In contact with organic matter tlie hypochlorous acid splits up into 
hydrochloric acid and oxygen, and it is on this liberated oxygen that 
its value as a disinfectant depends^ The calcium chloride remains 
behind as a deliquescent salt, and this is an objection to bleaching 
powder being mixed with lime for white washing, as the surface 
remains damp. It is important to remember that chloride of lime 
must be acidified, either slowly and spontaneously by the carbonic 
acid, or by the addition of hydrochloric or sulphuric acid or even 
vinegar, for any chlorine to be liberated. Weak acids only decompose 
the hypochlorite, leaving the chloride untouched, and evolve hypo- 
chlorous acid. Strong mineral acids, on the other hand, evolve 

To prove the necessity of acidification, D'Arcet and Gaultier de 
Claubry showed that air deprived of carbonic acid by a potash wash- 
bottle, and then passed over chloride of lime, was not disinfected. 

Good bleaching powder contains 34 per cent, of available chlorine. 
It is best used in the proportion of 1 part to 10 or 12 parts of water. 
It should be freshly prepared, and kept from light and air. When old 
it becomes damp and is then of inferior value. 

Similar preparations of aluminium and magnesium hypochlorites have 
been made by precipitating a solution of chloride of lime by sulphates 
of aluminium or magnesium. The latter has no special advantage, 
but the former has in addition the mordanting and clarifying and 
antiseptic properties of other aluminium salts (see Chloralum, p. 131), 
and might deserve more extended use. It is commercially used 
for bleaching paper pulp, under the name of Anderson's solution. The 
American " standard solution of chloride of lime " is thus described : — 
" Dissolve chloride of lime containing not less than 25 per cent, of 
available chlorine, 6 ounces to 1 gallon of water (4^ per cent.). Use 
1 quart for each discharge in cholera, typhoid, &c. Mix well, and 
leave in the vessel at least one hour before being thrown away." * 

For disinfecting clothes, the diluted Eaux de Javelle or Labarraque 
are better than chloride of lime. The fabrics must be washed soon 
after, or the fibres will be rotted. Of course the colours will be more 
or less afiected. Jaeger used a paste of equal parts of water and 
bleaching powder for disinfecting tuberculous sputa, t 

It must be remembered that chlorine and the hypochlorites also act 
energetically on other substances, so that any mixture of them with 
other disinfectants can only be endorsed by an experienced chemist, 
for, as a rule, these are only to be used apart. 

* Report of Committee on. Disirfectantii of American Public Health AsaocicUionf 
p. 235. 

t Arb. a. t/, Kais. Gesundh., 1889. 


One part of chloride of lime to 100 of water forms a liquid for 
washing the person in infectious diseases. The odour is most per- 
sistent, and may even convey a false sense of safety when tlie effective 
limit has long been passed. Semmelweis, however, in 1846 succeeded 
in stamping out of Vienna endemic puerperal fever by its use, and Sir 
Spencer Wells has advocated its use in this country, * 

Liebig contended that the continued action of chlorine or hypo- 
chlorites, as in the wards of hospitals, leads to lung diseases in the 
patients and attendants. Pettenkofer and Lehmann t say that 0*001 
to 0*005 per cent, of chlorine affects the respiratory organs ; 0*04 to 0*06 
per cent, produces dangerous symptoms ; and over 0*06 per cent, soon 
proves fatal. Undoubtedly chlorine will cause chronic bronchitis if in 
quantity, and disinfection with chlorine involves such a percentage of 
the gas as absolutely necessitates the removal of animals and plants 
from its vicinity. 

The Berichte der Choleracommission des Deutschen Reiclies, 1879, con- 
demns the use of chlorine as being dangerous, and Koch obtained 
unsatisfactory results with chloride of lime. J 

The same, however, is the case with sulphurous acid, nitrous gases, 
and still more with bromine and iodine, which are all intensely 
I)oisonous. § This action, coupled with the fact that the gas corrodes 
metal fittings and rots fabrics, has led in great part to its disuse for 
this purpose, and to its utility being confined to the disinfection of 
sewers and closets. Angus Smith, || on the other hand, points to the 
healthy appearance of men employed in bleaching factories ; he attri- 
butes this to the purification of the air. Notwithstanding these 
objections to its use, chlorine must be regarded as the most powerful 
of the disinfectants, being the only convenient gaseous body that can 
quickly destroy organic matter and consequently ensure perfect disin- 

" Chlorozone," a mixture of hypochlorites and permanganates, was 
formerly advocated. It was probably made by passing a current of 
chlorine through milk of lime, or a solution of soda or potash, in 
which finely ground manganese dioxide was suspended, or to which 
the manganous residues from the manufacture of chlorine were added. 
The chlorine oxidised the manganese compounds to permanganate, and 
at the same time formed hypochlorite. Such a solution would be 
attractive from its crimson colour, and would at the same time combine 
the oxidising properties of both these agents. 

* B. M. J., 1892. + Munich Acad., 1887. 

J Milt. a. d. KaU. GeJttmdh., vol. i., 1881. 

§ Wirkung der verdunnten Lufl a. d. Organ. Friiukel Sc. Goppert, Berlin, 1883. 

II Disinfectants and Disinfection, 1869, p. 49. 



Chambei'land and Fernbach, in a paper on the " Disinfection of 
Public Places and Dwelling Rooms,"* state that eau de Javelle, 
bleaching powder of a concentration of 1 in 120, and commercial 
peroxide of hydrogen, are found to be strongei* disinfecting agents 
towards pathogenic microbes than a 1 per cent, solution of mercuric 
chloride. These antiseptics, however, at the ordinary temperature, do 
not act at all on moist germs, or only do so after several hours. 
When heated to 40° or 50° C, or higher, moist germs are destroyed in 
a few minutes. Therefore, for rooms they must be heated. Dry 
germs can resist their action for several hours at 40° or 50° C, but if 
then moistened with water they are destroyed. It is noteworthy that 
a 0"8 per cent, solution of bleaching powder is far more active than 
1 in 120, whether for moist or dry germs, or whether hot or cold. 
Thymol, lysol, oil of turpentine, are, in comparison, bad antiseptics. 
In their experiments 100 grammes of bleaching powder were triturated 
with 1,200 of water, allowed to stand one hour, filtered, and diluted 
with 10 litres of water. 

This paper requires a few observations. Warming very easily 
converts "chloride of lime" into chloride and chlorate, and renders it 
almost inert as a disinfectant; it decomposes peroxide of hydrogen into 
water and oxygen, so rendering it useless ; eau de Javelle (potassium 
hypochlorite) similarly suffers ; hence great judgment would be 
required in the operation. It must be remembered that the 
alkaline hypochlorites do not evolve chlorine until after they are 
acidified, so that a strong alkaline solution may be less efficient 
than a weaker one in water, since the carbonic acid of the large 
quantity of water liberates a greater amount of hypochlorous acid. 
With reference to the prescription for chloride solution for practical 
purposes, an hour is not necessary if well agitated, and filti*ation is 

Sheridan Delepine t uses chlorinated lime for disinfecting rooms 
which have been contaminated by tuberculous patients, as follows : — 

(1) A solution of chlorinated lime (1 in 100) should be prepared; 

(2) the walls, ceiling, and floor should be washed with this solution in 
the same way as lime or whitewash is usually applied ; (3) this process 
should, for safety, be repeated three or four times in succession ; 
(4) the room should then be closed, a small safe petroleum stove being 
first placed in the middle of the room, and precautions taken to prevent 
any chance of fire ; over this stove, a large tin basin fuU of water or 
bleaching powder solution should be placed. To secure acidity to the 
air, he further suggests suspending in the water bath a capsule 
containing hydrochloric or acetic acid. Three hours is suflicient time 

♦ Ann. de VInstitut Pasteur, 1893, vol. vii., p. 433. t MecU Chron., May, 1894. 


foi' an ordinary room, and 6 ozs. of bleaching powder, using 3 pints of 
water for each washing, is the quantity lie recommends. 

W. E. Crow and Frank Browne, at Hong Kong, during the plague 
in 1894, used free chlorine generated from ^ lb. chlorinated lime, 
mixed with 1 quart of water and 1 quart of dilute sulphuric acid (1 in 5). 
This quantity was used for each room. 

The ^^ Her mite" or Electrolytic Process. — About 1859, Charles "Watt 
discovered that when a solution of a chloride of the alkalies or alkaline 
earths was electrol^'sed, a solution similar to bleaching liquid was 
formed. It presumably contained chlorides and hypochlorites, but 
apparently was more active than a solution prepared in the ordinary 
way. Magnesium chloride was said to be preferable. Such a solution, 
originally intended for bleaching paper-pulp, has recently been 
advocated by M. Hermite for sanitation, and sea-water, containing as 
it does the chlorides of sodium, calcium, magnesium, and potassium, is 
proposed as a cheap and suitable mateiial. He uses a special form of 
"electrolyseur" for affecting the electrolysis, and proposes to pump the 
solution through a system of pipes to the place of use, and thus render 
it available for domestic use, and for local flushing of sewers, latrines, 
&c. Dr. Piton's report to the Mayor and Corporation of Brest, refer- 
ring to experiments on this system at Nice, states that the Hermite 
solution, diluted to a strength of about \ gramme of free chlorine per 
litre, does sterilise the fa?cal matter in the sewers, but that, in spite of 
the rapid absorption of chlorine, the disintegration of paper and fjecal 
matter is no more rapid than when ordinary water is employed. The 
system was tried at Worthing in the early part of 1894, and Dr. C. 
Kelly, the medical officer of health for Worthing, in a report incor- 
porating the chemical and bacteriological analyses by Dupre and 
Klein, " dismisses the experiences of the trials made by the Worthing 
Corporation as having failed to realise the claims of the inventor, 
besides involving serious considerations of expense, both in the 
production of the fluid and the method of applying it to houses." 
This report was questioned by the English agents, Messrs. Paterson. 
«fe Cooper, who have formally protested. Dr. Riifier and Sir H. Roscoe 
have reported more favourably on the process, and it has been further 
tried at Havre, I'Oriente, and Nice. 

In the patent of Hermite, Paterson k Cooper, No. 22,279, 1893, 
the apparatus is described, and the strength of the fluid obtained is 
stated to be 2 grammes of free chlorine per litre, and for use it is 
recommended to be diluted six or seven times. A current of 300 
amperes at a pressure of 6 volts is required to decompose the sea 
water in the electrolyseur. In patent No. 6,495, March 31, 1894, a 
method of protecting the iron pipes from corrosion by the chlorine is 


The Lancet Report on the Hermite process and the experiments at 
Worthing * comes to the following conclusions : — ■ 

By electrolysis of the magnesium chloride in the sea water, magnesia 
and chlorine jire liberated, which subsequently combine to form 
magnesium hypochlorite Mg (OCl)^ and magnesium chloride. This 
liquid may be regarded as the magnesian equivalent of bleaching 
powder solution. The magnesium hypochlorite dissociates into 
magnesia, which deposits on the walls and floor of the electrolyser, 
and free hypochlorous acid, which remains in solution. 

Mg(0Cl)2 + 2H2O = Mg(0H)2 + 2H0C1. 

The Hermite solution then practically resolves itself into a dilute 
solution of hypochlorous acid, and may be cheaply imitated by passing 
carbonic acid through a solution of ordinary bleaching powder. It is 
admitted, however, that this "artificial Hermite" gave in bacterio- 
logical examination " varying results, and could not be depended on 
to exert constantly an equivalent action to the Hermite solution." 
Chemically, however, the two solutions exhibited very close resem- 

The strength of the electrolysed sea water in chlorine, or its equi- 
valent, as determined by the arsenious acid process t is 0-5 gramme 
•CI per litre. Urine at once acts on it, depriving it of about half its 
chlorine strength. 

In comparative experiments on the action on ordinary stools of 
Hermite fluid, bleaching powder solution, and milk of lime 2i and 
I per cent., it was observed that, as expected, the bleaching powder 
was not so immediate in its effect, but in a longer period the final 
result was similar. " Although in consequence of this the bleaching 
powder does not exert so rapid and immediate effect as the more un- 
stable Hermite solution, yet the weaker solutions of the former, owing 
to their stability, in the end produce a much more complete process of 
sterilisation than in the case of Hermite solutions of similar dilution." 
The action of the full-strength Hermite fluid on the pathogenic organ- 
isms of diphtheria and of cholera, and the Staphylococcus pyogenes 
aureus were very satisfactory ; but in the case of anthrax it was less 
conclusive, as the cultures used were proved to be somewhat feeble. 
Both gelatine plate and broth cultivation were tried. It was far more 
efficacious than even strong solutions of phenol. As compared with 
mercuric chloride, the rei)ort gives the preference to the Hermite fluid 
as a practical disinfectant. It sees, however, no advantage in the 
Hermite solution over the product obtained by treating chloride of 
lime in solution with carbonic acid. 

* Lancet, May 26, 1894. t Methods rf Anali/sis, Chap. xv. 


Sir Henry Roscoe and Lunt have also criticised the Hermite process 

Chlorates. — Being more stalile than the hypochlorites, the chlorates, 
although they contain more oxygen, give off neither oxygen nor 
chlorine unless a strong acid be added. Such a mixture is a very 
strong oxidant, but it evolves besides chlorine, more or less of the 
explosive and poisonous chlorine oxides known as " euchlorine." 

Wiederhokl recommends cholera excreta to be treated with potas- 
sium chlorate and hydrochloric acid. The odour of the gases evolved 
is very unpleasant, and powerfully attacks the eyes. The action is 
very rapid, but is soon exiiausted ; an objection which, independent 
of cost and unpleasantness, renders other preventives preferable, t 

By themselves, chlorates are mildly antiseptic. Dr. O'Neill found ^ 
that the chlorates of potassium and sodium had no preservative action 
ou beef tea. Perchlorates are similar. § 

Hydrochloric Acid. — Since almost all bacteria grow best in neutral 
or alkaline solutions, and many are killed by even weak acidity, the 
mineral acids are valuable disinfectants. Davaine|| states that the 
virus of anthrax or septic fever is definitely destroyed by the following 
proportions of acids : — 


^ Septicajmia. 




1 in 3000 
1 „ 5000 
1 „ 6000 

1 in 1500 
1 „ 3000 

Vallin, from his own experiments, thinks that a larger amount is 

Acid fumigations for disinfection, especially with hydrochloric acid, 
•were introduced by Guy ton de Morveau in 1805. Previously, in 1773, 
the stench from the catacombs under the church of St. Etienne at 
Dijon (which, of course, would be very ammoniacal) was entirely 
removed in twenty-four hours by pouring 2 lbs. of sulphuric acid on 
6 lbs. of salt in a vessel heated by a brazier of hot cinders. 

NaCl + H2SO4 = NaHSO* + HCl. 
The next year the hospital at Dijon, where typhus was raging, was 
successfully disinfected by the same means. After several other trials, 
this process was strongly approved by the Academy of Sciences. For 
350 cubic metres of space, 200 grms. of salt and 240 grms. of sulphuric 
acid of 60° B. were recommended. 

* Journ. Soc. Chem. Ind., 1895. f Reichardt, Deslnfectionsmitlel, p. 95. 

*Army Medical Report, 1872, p. 202. § Compare Periodates, p. 76. 

II "Virus de Septicemic," Gaz. Med., Jau. 10th, 1874. 


Its penetrating power and solubility, combined with cheapness and 
facility of employment, are its chief merits. The gas is less irritant 
than chlorine, but has a powerful pungent odour. Although it is now 
seldom used, it is well worth further experiment. Guyton de Morveau* 
states that " Dr. Cabanellas, in the terrible epidemic in Andalusia in 
1780, having exposed to the simple vapour of hydrochloric acid for 16 
days, pieces of very fetid flesh, there remained not the slightest odour 
of putrefaction." 

Against its employment are the experiments of Pettenkofer and 
Lehmann, t in which animals exposed to 3*4: per cent, of the acid 
in air for one and a-half hours were seriously affected, and many died. 
Strong men can only stand 0*5 per cent, for a short time, and the 
limit for workmen used to it is O'l per cent. Recent experiments 
have shown that less than this is destructive of a large number of 
pathogenic bacteria. 

Chlorides. — Many of the chlorides have marked antiseptic properties. 
Those of the heavy metals, such as iron, aluminium, and zinc, will be 
noticed under the respective metals. 

Sodium chloride, common salt, is generally employed for the preser- 
vation of meats, butter, &c. This it does less by its own antiseptic 
power than by removing in the brine the soluble and more puti'cscible 
organic constituents, and by hardening the remaining insoluble fibres. 
The brine becomes sometimes contaminated with ptomaines, and para- 
sitic low organisms are produced. M. Goubaux has shown that it can 
sometimes acquire a high degree of toxicity. However, it is genei'ally 
thrown away and the meat washed before use. 

Sodium chloride is not a disinfectant. Pringle, who was one of the 
first to introduce direct experimental methods in the study of disin- 
fectants, in his Memoire sur les Substances septiques et antiseptiques, X 
which is of classical interest, and contains details of a series of most 
carefully devised experiments, found sodium chloride so weak an anti- 
septic that he placed it the lowest in his scale of bodies investigated. 
In further experiments he proves that sodium chloride more frequently 
hastens putrefaction, for, in the proportion of 10 to 20 grains to 2 grains 
of beef and 2 ounces of water, the salt softens and dissolves the meat, 
and "by a septic virtue favours its digestion." He cites other authors 
who have admitted the " putrefiant " nature of sodium chloride. 

Bouley,§ and Arloing, Coi'nevin & Thomas |] find that even a satur- 
ated solution of salt is without action on the virus of anthrax. 

Bromine. — Bromine, formerly employed by Ozanam to combat the 
development of false membrane in diphthei'ia, is likely to be more 

* Traits, 1805. t Munich Acad., 18S7, 179. X Acad, des Sciences, 1750. 
% MMiclne VHerina'ire, p. 467. \\Lyon Hedical, June, 1882. 


generally used as a substitute for chlorine in the event of an increase 
in tlie demand for a volatile liquid which easily gives off, when 
exposed, large quantities of potent gas. It is now made in large 
quantities and comparatively cheap. Its odour and action on the 
mucous membranes are worse than those of chlorine. According to 
Pettenkofer and Lehmann, men cannot stand more than '002 to "004 
per cent, unless habituated to it ; if so, not more than 0*01 per cent. 
This shows that fumigation with chlorine or bromine in presence of 
men or animals is of no value, since bacteria require 3 per cent. CI for 
three hours, or 0*4 per cent, for twenty-four hours ; hence it can only 
be used under the direction of experts. It is also intensely corrosive. 
The chemical action is similar to that of chlorine, but slower. It is 
much more soluble, bromine water containing 3 per cent, of the ele- 
ment, and possessing greater stability than chlorine water. Bromine 
stands intermediate in power between chlorine and iodine, as its 
atomic weight would indicate. Wernitz * finds its efficiency against 
diflferent known organisms varies between 1 in 1,000, and 1 in 2,840, 
and 1 in 31,100, iodine lying between 1 in 1,000 and 1 in 24,000. 
Jalan de la Croix,f to kill bacteria in beef tea, required of bromine, 
1 in 2,550, of iodine 1 in 2,000 ; to sterilise the germs required, 
bromine 1 in 336, iodine 1 in 410. To prevent growth in raw beef 
tea exposed to air, 1 in 5,600 of bromine, 1 in 2,010 of iodine. 
"Wilson X states that bromine water of 2 per cent, strength destroyed 
Bacillus anthracis in one day. 

Bucholtz § finds the growth suppressed by chlorine, 1 in 25,000 ; 
iodine, 1 in 5,000 ; bromine, 1 in 3,333, as compared with sulphur 
dioxide, 1 in 666. Arloing, || confirmed by Koch, finds that bromine 
is the most powerful of all destructives to the virus of anthrax and 
tubercle ; even killing the dried virus, upon which chlorine does not 
act. To summarise, 4 parts of bromine appear to be about equal to 
5 parts of iodine, and a safe minimum is about 1 in 2,000, or com- 
paratively — 

CI 0-02 per cent. Br 0*05 per cent. I 0-062 per cent. 

The Prussian Government ordered (March 13, 1879) that when 
strong disinfection of stables was necessary, after removal of the 
animals, for every 18 cubic metres of space a flask of 250 grammes 
of bromine should be planted in shell-sand, iron articles being as far 
as possible removed, and doors and windows closed. The flask is 
upset, and the operative quickly retires. 

After twenty-four hours the place is opened, and ventilated for 

* Wirhtng der Antiseptica, Inaug. Dissert., Dorpat, 1880. 

t Verhallen den Bakterien, Archiv.f. exp. Pathol., 1881. :J: Hygiene, 1892, p. 525. 
• § Archiv.f. exp. Pathol., vol. iv., pp. 1 to SO. I! Lyon Medical, 1882. 


twelve hours before the stable is again used. Its cost was then about 
2^d. per cubic metre, but since that date the price of bromine has 
been much reduced.* All the bromine would be used without 
attention, and the method seems to have the merit of neatness and 

Dr. Franck, to whom many of the improvements in the manufacture 
of bromine are due, has introduced under the name of bromuni 
solidijicatum, a very convenient form.f This is made by first forming 
porous rods of kieselguhr (infusorial sand), and molasses baked until 
hard, and then saturating them with liquid bromine. Each stick 
contains about 75 per cent. Br by weight, so that a given weight of 
disinfectant can be obtained by using the necessary number of sticks. 
At present, however, they cost much more than ordinary liquid 

Fischer and Proskauerj have made a number of experiments with 
the halogens. For bromine, a stoppered bottle was filled with 
siliceous earth saturated with bromine ; when required the stopper 
was removed, the bottle placed near the ceiling of the room, and the 
vapour allowed to diffuse. They prefer chlorine, on the ground that 
bromine is dearer and more destructive to cotton and wool. 

They also draw attention to the importance of the presence of 
moisture when the halogens are used as disinfectants. 

A mixture is made by Messrs. May tk Baker, of Battersea, London, 
consisting of a soluble bromide and bromate (preferably of sodium or 
potassium) mixed with an alkaline bisulphate, such as NaHSO,j. The 
addition of a small quantity of a terpene, essential oil, camphor, or 
hydrocarbon increases the keeping power of the disinfectant. This 
mixture, when moisture from the air is absorbed, liberates the halogen 
thus : — 

5NaBr + NaBrOg + eNaHSO* = 6Na2S04 + SHjO + SBrg. 
It is known under the name of " Bromidine."§ 

The bromonaphthalene night-lights, which owe their efficiency to 
the liberation of this element, give off the bromine only when 
burning. II Dr. C. R. A. Wright has patented the use of monochlor- or 
bromnaphthalene dissolved or suspended in solution of resin soap\. 
He also proposed using these compounds in powders by mixing them 
with sawdust or plaster of Paris, «fec.^ 

* Compare Mehlhausen's experiments with chlorine, ante, p. 61. 
t Patent No. 254, 1883. 

t Mitlheilungen aus clem Kaiserlichen Gesundheitsamte, Berlin, 188i. 
§ Journ. Soe. Chem. Industry, 1887, p. 378 ; W. D. Borland, patent No. 6191, 
\\ Journ. Soc. Chem. Industry, 1890, vol. ix., p. 407. H Patent No. 4,950, 1893. 


Iodine is a less powerful disinfectant, according to Koch, than 
chlorine or bromine. His experiments have the objection of having 
been performed with an alcoholic solution of iodine, while both bromine 
and chlorine were used in aqueous solutions. Cash's more recent 
work shows that when used in rates proportional to the atomic 
weights, iodine is more energetic than chlorine, bromine being inter- 
mediate in its character. 

Iodine water is practically stable, but is much weaker than bromin^e 
water. Its vapour is eight and a-half times heavier than air, and, 
therefore, difficult to diffuse. 

Iodine does not act by oxidation like chlorine and bromine, but 
directly combines with the protoplasmic matters of organisms, thereby 
poisoning them. It is not a good deodorant, and has the disadvantage 
of producing brown or blue stains when organic materials come into- 
contact with it. Its high atomic weight (127) adds to its cost, but, 
being a solid, it is convenient, safe, and portable. Lamps of various 
kinds have been devised for vapoi'ising and diffusing it in a finely 
divided state. 

Messrs. Casson and Brown proposed using candles containing iodine 
and salicylic acid incorporated with the wax. These, when burnt, give 
off vapours of iodine and phenol. If the combustion is too free, iodine 
alone is volatilised, the phenol being decomposed. These candles are- 
said to remove all odour of sulphuretted hydrogen and tobacco smoke, 
and are recommended for asthma, hay fever, <kc. 

Better than these are the "Sussex patent night-lights," in which 
iodoform is mixed with the wax. In burning, hydriodic acid is- 
probably lil>erated first, and then decomposed by the heat into- 
hydrogen and iodine. 

Watson &, Fulton* have proposed candles containing iodine and 
sulphur, which profess to give off the vapour of iodine and sulphur 
dioxide gas, with no hydriodic acid. 

A. J. Shilton f has taken out a patent ;J: for a solution of iodine 
dissolved in an alkaline iodide in the proportion of 1 oz. of iodine and 
2 ozs. of potassium iodide to 1 gallon of water ; also § a mixture of 
2 ozs. potassium iodide, 1 oz. iodine, and 16 ozs. ammonium chloride > 
these in strong solution are diluted with 15 to 20 parts of water, and 
diffused into the room by a spray producer. Davaine and Marchal 
de Calvi were the first to propose iodine as an antiseptic. The former 
found that 7 milligrammes of iodine sufficed to kill anthrax bacilli in. 
1,000 of liquid.lj Griffiths H states that 1 milligramme of iodine ia 

* Patent No. 10,876, 1S85. f Joum. Soc. Chem. Industry, 1890. 

X Patent No. 2,537, 1889. § Ihid., 1885, p. 239. 

II Bui. de I' Acad, de MMecine, July 27, 1880. 
^ Proc. Roy. Soc. o/Edin., vol. xv., p. 37. 


100 c.c. of nutrient broth (1 part in 100,000) destroyed the vitality of 
Sarchia lutea, a chromogenous coccus, in half an hour. 

Dr. Williams asserts that iodine greatly reduces the number of 
tubercle bacilli and prevents spore-formation. " We can inject with 
im2)unity into the blood of a dog, for each kilogramme of body weight 
-02 or "03 gramme of free iodine dissolved in 2 parts of .sodium iodide. 
This for an ordinary man would be 1*4 to 2*1 grammes. Beyond this 
it is poisonous, and death occurs in tw^enty-four hours. Potassium 
iodide has an injurious action on the heart." * The importance of these 
results is shown by the consideration that disinfectants externally 
applied cannot arrest the progress of disease germs already established 
in the body, since, as Koch says, " before they destroy the parasite, 
they kill the host." The choice lies between real though dangerous 
disinfectants like chlorine, and antiseptics like carbolic acid which 
require to be of such strength as to be expensive and almost inapplic- 
able. Prophylactic treatment, like injection, or Pasteur's and Koch's 
inoculation, would have to supplement effective disinfection externally. 
Koch states that to check Bacillus anthracis in man, by internal treat- 
ment, 1 2 grammes of iodine must be constantly in circulation. 

Iodine inhalation has proved valuable in phthisis and other lung 
•diseases. Of course, it is very irritant if too strong, but a diluted 
vapour is tolerated. f 

Iodine Trichloride, ICI3, was proposed as a disinfectant by von 
Langenbach. It occurs in orange-yellow needles, easily soluble in a 
moderate quantity of water to a colourless acid solution of extremely 
irritant odour, affecting the eyes. It is best kept as a 5 per cent, 
solution. A solution of 1 in 1,000 keeps for several days; after a 
time it decomposes in the presence of water into hydrochloric and 
iodic acids, and loses much of its power. It is easily made by passing 
a current of chlorine through water in which iodine is suspended with 
constant agitation. It is well known in oi'ganic chemistry that the 
presence of a trace of iodine favours greatly the action of chlorine on 
organic bodies, hence it is not improbable that a small quantity of 
iodine, or of its chloride, might be a valuable adjunct to chlorine dis- 
infection. Von Langenbach pronounced iodine trichloride to be one 
of the most powerful disinfectants known, an aqueous solution con- 
taining from 0-67 to 1 gramme per litre, being as powerful as a 4 per 
cent, solution of phenol. It can be used for cleaning the hands and 
instruments, and ranks next to mercuric chloride as a germicide. 

Traugott + finds by experiments on hospital patients that it is not 
poisonous, that its effect on germs is very marked, the bacteria of 

* Proc. Roy. Soc, 1884. t Proc Boy. Soc. Edin., vol. xv., p. 54. 

:;: ZeitF.fur Eyj., 1893, p. 427. 


typhoid, cholera, and diphtheria being destroyed by 1 per cent, in one 
minute, the two latter by 1 per 1000 in the same time, while typhoid 
with 1 per mille required five minutes. It was very successful when 
tried on the dejecta of cholera. The price of a 1 per 1000 solution is 
about one-quarter that of 3 per cent, carbolic acid, which it excels in 
efl&ciency. Dr. Otto Riedel * had previously in a number of experi- 
ments established its value, pronouncing it not very })oisonous, and as 
having about three times the power of phenol. Webb states that 
chloride of iodine, mixed with talc and stearin or petroleum and burnt, 
gives an active vapour. + 

lodates are disinfectant, easily giving off oxygen and even iodine. 
Iodine dissolves at once in an alkali, producing a mixture of iodide 
and iodate, which, on the addition of an acid, liberates hydriodic and 
iodic acids. These acids interact on one another, setting free iodine 
as a precipitate if strong, or in solution if weak. 

HIO3 + 5HI = 3I2 + 3H2O. 

Sonstadt has proposed J a mixture of calcium iodate and an alkaline 
salicylate for destroying the disease-bacteria of pleuro-pneumonia, &.C., 
by spray or vapour. Stronger solutions are made by adding sodium 
or potassium citrate, which increases the solubility of the iodate. "It 
may be used as a lotion for sores, bites, or wounds, by injections for 
cholera or typhoid, or internally." Griffiths states § that a solution 
containing 0*5 per cent, of potassium iodate destroys several microbes. 

Periodates. — Salts of periodic acid, HIO^, have been recently much 
extolled as disinfectants. Weaver asserts that "all putrefactive 
microbes and the poisonous ptomaines they create are destroyed by 
1 in 250,000 of ' periodate,' although singularly the aerial moulds are 
not much affected by it." || One of the salts has been investigated by 
Klein, who states that "it is a very powerful disinfectant, instantly 
killing cholera comma bacilli, and typhus bacillus when used 1 in 5,000 
of water." 

Periodic acid is made by treating perchloric acid with iodine. 

2HCIO4 -f I3 = 2HIO4 + CI2. 
The periodates are formed by treating an iodate and an alkali with 
chloribe, or treating a mixture of iodine and an alkali with excess of 
chlorine : 

NalOs + 2NaOH + Clj = 2NaCl + HjO + NalO^. 

A great number of periodate preparations have been introduced. 
" Creo " is a disinfecting powder containing tar, alkali, and periodate, 

* Arb. a. d. Kais. GesundheUaamte, 1887. 
t Beichardt, DesinfeclionamUlel, 1881, p. 68. t Patent No. 4,920, Oct., 18S3. 
§ Proc. Boy. Soc. Editi., March, 1889. 11 Builder, Sept. 11, 1SS9. 


for drains, ifec. Klein states that a 1 per cent, solution kills cholera 
and typhoid bacilli in five minutes. Another disinfecting powder 
contains periodate with eucalyptol. lodate soaps are made. 

Griffiths has given a very favourable report on ferric periodate, 
1 in 250, as destroying Bacillus anlhracis and its spores. 

The constitution of these various mixtures seems not to be clearly 
defined, and further experience is necessary before their very wide 
claims can be admitted. Their expense and possible instability have 
been adduced as an objection for public and extended use. It i.s 
notable that the higher oxygen compounds of iodine in the chemically 
pure state are known to be very stable and do not easily give up their 
oxygen. The activity of these " periodate " preparations cannot there- 
fore be attributed to liberation of oxygen. They present some 
analogies with the " Hermite " fluid. 


Nearly all halogenated organic compounds have antiseptic and 
anaesthetic properties. The aromatic compounds are more antiseptic 
and less anjesthetic than derivatives of the hydrocarbons which have 
not a closed chain. They are, therefore, to be preferred, although 
chloroform and especially iodoform are still largely used. 

Chloroform, CHCI3, is a strong antiseptic, and prevents putrefaction 
so long as it is present. It is very volatile, boiling at 61° C, has a 
high specific gravity ( 1*497), and is almost insoluble in water. These 
I)roperties, its cost, and its poisonous action on animals, render it of 
very limited application, almost confined, indeed, to preserving medi- 
cinal infusions. 

A solution of 5 per cent, chloroform in spirit is sold in small bottles 
as a preservative, but is not patented. Its peculiar sweet taste and 
odour are instantly recognised, even in presence of sugar. 

Vallin states * that to kill already-grown bacteria requires the rela- 
tively large dose of 1 per cent, of chloroform, and that it does not 
fcterilise except when equal parts of chloroform and water are used. 

F. Bouillat t has also obtained unsatisfactory results with the 
chlorides of carbon, CCI4, C2CI4, and C2Clg. 

Bromoform, CHBr.,, is similar, but more expensive, less volatile, 
equally insoluble, and less stable. 

Iodoform, CHIy, a yellow crystalline powder of persistent and dis- 
agreeable odour, volatile, soluble in alcohol, but almost insoluble in 
water, is a powerful antiseptic (proposed by Von Moorhof, of Vienna, 

* TraM des Diainfectants, p. 206. 

t Ze'dHch.f. prakliich. Chem., vol. xxv., p. 300. 


in 1881), and is much used in hospitals for dressings, &c., in tlie form 
of iodoform gauze. A liquid containing iodoform in solution or sus- 
pension is readily made by adding to tincture of iodine strong liquor 
potassa? or liquor sodse until the colour is destroyed, and pouring this 
solution into a large bulk of water. 

Iodoform night-lights have been already mentioned (p. 73). 

To prevent the putrefaction of bronchial mucus in pulmonary dis- 
eases, Chiaramelli recommends the internal administration of iodoform. 
The medicine is eliminated by the lungs, hence its action would be 
less irritant than in direct inhalation.* 

The United States Pharmacopoeia gives the following formula for 
iodoform gauze : — 

Iodoform, 10 parts. 

Ether, sp. gr. '725, 40 ,, 

Alcohol, „ •820 40 ,, 

Tincture of benzoin (1 in 5), . . . . 5 ,, 

Glycerine, ....... 5 ,, 

Gauze muslin, A sufficient quantity. 

"Dissolve the iodoform in the ether, then add the alcohol, benzoin, 
and glycerine ; immerse in a weighed quantity of this solution the 
exact amount of muslin required to absorb it all, so as to make a 
product of the required strength in iodoform (generally 30 to 50 per 
cent.), dry it horizontally in a dark place. Preserve it in air-tight 

Bisulphide of carbon has been suggested as a solvent, but its odour 
and inflammability render it objectionable. 

Iodoform is also used in fine powder for dusting wounds, in bougies 
with cacao butter, in emulsion of 10 to 50 per cent, with glycerine, 
water, and tragacanth, and in solution of 1 part iodoform with 11 
of vaseline to 9 of benzene with 2 drops of oil of wintergreen for 

The antiseptic power of iodoform has recently been much disputed. 
While the Lancet asserts f that it is a much better antiseptic than 
most other substances which are used for the same purpose, and is of 
much more value than carbolic solution, and while Sir Joseph Lister 
found it of the highest value for wounds, Messrs. Hehn and Rosvinj 
maintain % that in a long series of experiments they have proved that 
it is not antiseptic at all, but only a desiccant. " Sterilised iodoform 
jelly, when inoculated with micro-organisms, was found to be full of 
them, all growing freely, on the third day." Riedlin asserts § .that 
" as a parasiticide it is feeble and inert, but it dries the surface of 

* Lyon Midical, 1882, p. 362. + Lancet, 1887, p. 595. 

J Chem. NticH, voL Iv., 1887. § Arnould's Hygiene, p. 498, 1889. 


wounds." Miguel in hisjtable ma^ks it as very strongly antiseptic ; '^ 
but Bouillat f found that 10 per cent, of iodoform did not arrest putre- 
faction change in extract of panci'eas. The truth is, as pointed out by 
Behring, that it produces its undoubtedly beneficial effects, not by 
acting directly on bacteria, but by inducing chemical changes in their 
toxic products. He has ascertained that some of these toxines are 
altered chemically by iodoform and rendered harmless. 

Drs. Forster and Marchand % are in favour of iodoform. Dr. W. 
D. Miller does not recommend it for dental purposes. 

Its utility must be limited to surgery, and perhaps also to fumiga- 
tion in the candles already described (p. 73). 

Ethyl iodide is unstable and easily gives off iodine, of which it con- 
tains 81 per cent. It has proved useful in phthisis and asthma, in 
doses of 10 to 15 drops inhaled several times a day. Iodine may be 
detected in the urine and saliva soon after inhalation. It possesses 
germicidal powers, and readily destroys Bacillus tuberculosis.^ Ethyl 
bromide has also been suggested. || Their cost and low volatility would 
negative them as disinfectants. 

Organic Compounds containing Iodine. — The halogens can only exert 
their disinfectant action in the free state ; in combination they may 
modify the properties of the compound, and make it possibly more 
antiseptic, but they cannot be disinfectant in the sense of burning up 
the organisms as chlorine, bromine, and iodine in the free state do. 
It is true that some of these bodies are decomposed more or less slowly 
by light setting free some of the halogen, but this would be a pro- 
tracted, expensive, and wasteful process. 

Europhen (isobutyl-cresol hydriodide) ; iodol (tetra-iodo-pyrroline) ^ 
aristol (di-iodo-di-thymol) ; and sozo-iodol (sodium-di-iodo-paraphenol 
sulphonate) have been proposed as iodoform substitutes, and will be- 
further described among the aromatic antiseptics. 

The periodides of the phenols have been patented for antiseptic 
use. IT 

Fluorine itself is more energetic than chlorine, but on account of 
the intensity of its action and the diflficulty of its preparation, is not- 
likely to be made available. 

Many years ago William Thomi)Son found that hydrofluoric acid,, 
fluorides (acid or neutral), and silicofluorides (fluosilicates) were anti- 
septic. He patented their use under the name of "Salufer." Sodium 

* LcK Organixmes Vivants de VAtmonpliKre, 1883, p. 289^ 

t Zeitdch.f. praklisdi. Chem., vol. xxv., p. 300. 

J.4rcAir. Path. Anat., vol. xciii., 1883. § Griffith's ifiero-organismSyrp. 208. 

II Sormani, Atti deWInst. Lombardo, 1887. 

IT Bayer of Elberfield, and Willcox, Patent No. 7,782, 1892.. 


silicofluoride is a powder possessing no smell and only a slight saline 
taste, and is sparingly soluble in water. A saturated solution 
contains 0*61 per cent, of the salt, and is not irritating to wounds. 
Thompson states that it is stronger than a 1 per 1000 solution of 
mercuric chloride, and not poisonous. It is commonly sold in cubes 
of a definite weight, being thus more easily carried. One cube 
dissolved in a quart of water is suitable for washing the hands. It 
is highly spoken of as a non-toxic antiseptic and deodorant. 

A "Salufer" wool is also made.* 

The recent work of Dr. Effront on the use of mineral acids for 
the suppression of undesirable fermentations in breweries and dis- 
tilleries, has demonstrated that hydrofluoric acid has a powerful 
antiseptic action, and protects the wort from lactic and butyric 
fermentations. The ammonium and potassium salts have also been 
\i8ed successfully in this way. All the fluorides appear to possess 
the further remarkable property of increasing the diastatic power of 

Dr. Griffiths in several experiments has found that a 0-4 per cent, 
solution of sodium silicofluoride was fatal to the bacteria tried — 
viz.. Micrococcus prodigiosus and Bacillus cedematis maligni. % 




Oxygen and Ozone : Ozonizers — Peroxide of Hydrogen — Carbon Dioxide — Nitri© 
Acids and Oxides of Nitrogen : Nitrous Ether — Sulphur and its Com- 
pounds : Sulphuretted Hydrogen — Sulphurous Acid — Sulphites and Bisul- 
l^hites — Thiocamf — Sulphites in Food — Sulphuric Acid — Sulphates — 
Bisulphide of Carbon — Boric Acid: Borax and other Borates — Boroglyceride 
— Boric Acid in Food — Physiological Efifects — Influence of Gases on 

Oxygen is the chief and natural disinfectant, burning up gradually all 
organic substances into carbonic acid and water. This process, called 
decay, affects the various bodies very differently; the more putrescent 
compounds are generally the most rapidly destroyed, so that fresh air 
■would be all that is needed to keep our surroundings healthy, if it 

* Chem. News, vol. Ivi,, p. 132. t Monit. Sdeiit., vol. vi., 1892, p. 81. 

X Proc. Roy. Soc. Edin., vol. xv., p. 37. 


were possible to ensure that all matter likely to be a source of con- 
tagion were liberally supplied with the oxygen of the air. The 
oxidation of the products of those niicro-organisms which are poisonous 
to man, such as the " ptomaines " and " toxines," which Selmi was the 
first to investigate, is no easy task. The bacteria which produce these 
toxic compounds have a higher vitality than man, and most strong 
chemical agents which can kill bacteria have also a toxic effect upon 
more complex organisms. No man can endure an atmosphere that 
will kill these bacteria. Only the halogens, chlorine, bromine, and 
iodine can penetrate their envelopes, and these cannot be given in 
sufficient quantity when man is present. It is, therefore, absolutely 
iiecessary to remove patients and seal rooms in order that disinfection 
may be successfully accomplished. 

The importance of the distinction between an antiseptic, which 
simply stupefies the germs of disease for a time, and a disinfectant, 
-which kills them and leaves the room sterile, cannot be too strongly 
insisted upon. The use of antiseptics merely puts off the era of putre- 
faction, and while arresting temporarily the evil, does not eradicate it. 

The " molecular" or ordinary oxygen of the air acts slowly. When 
liberated from various chemical compounds like permanganate and 
peroxide of hydrogen it is said to be in a " nascent '"' or atomic con- 
<iition, and is then far more active. 

A number of inventions attempt to increase the power of atmo- 
spheric oxygen by mechanical means. Thus it has been proposed to 
compress the oxygen into water, increasing the solubility, and there- 
foi'e presumably the activity.* Similarly J. Konig, with a view to 
increase the rate of atmospheric oxidation of the waste water of 
tanneries and slaughter-houses, produces a flow over a tinned iron net 
4'5 metres high, with a breadth of 1 metre for every 12 litres per 
minute, giving as the result of an experiment : — 

Per Litre. 


Sulphuretted Hydrogen, 
Sulphuric Acid, .... 


3 c.c. 
20*4 milligrms. 


9 c.c. 

0'9 milligrms. 

proving that strong oxidation had taken place, f On the same prin- 
ciple polluted water flowing over weirs and waterfalls is oxidised and 
becomes clear and brilliant. Pathogenic organisms may not, however, 
be entirely removed by such aeration, and may set up changes again 
lower down. 
* E. Scruby, Patent No. 5330, 1891. t Chem. Zeilttng, vol. viii., pp. 56, 1003. 


The self-purification of rivers in this way is now accepted by most 
chemists, the natural aeration being aided by infusoria and vegetation 
in removing most of the dead organic matter and in reducing the 
number of micro-organisms present. * 

Ozone, O3, is present in country air, but absent in towns, being 
quickly consumed by the organic matter present in the air. It is an 
allotropic modification of oxygen produced by atmospheric electrical 
disturbances, but owing to its energetic oxidising, it is soon destroyed. 
It closely resembles chlorine in its chemical activity. Its energy has led 
several inventors to propose electrical means for disinfection, as ordinary 
oxygen becomes ozonised when subjected to an electric current. 

Hagenf proposes to ozonise oxygen by the usual silent discharge 
method, then to pass it over the articles to be disinfected, or introduce 
it into sewage, when the ozone, O3, decomposes into Og (ordinary or 
'* molecular" oxygen), and the atom of "nascent" oxygen, which acts 
upon the organic matter more rapidly than when in the ordinary 
molecular condition. The remaining ordinary oxygen, mixed with a 
little carbonic acid, derived from the oxidation of organic matters, is 
carried back and ozonised again. The process can, therefore, be made 
a continuous one, the carbonic acid being absorbed by lime. It must 
however, be borne in mind that : — 

1. No ozoniser yet invented raises the ozo7ie to more than 10 per cent., 
and generally not over 1 or 2 per cent., and this strength is hardly 
sufiicient for sewage. It is well known that, owing to diflfusion laws, 
a gas acts far less actively when mixed with a large quantity of 
another inert gas. 

2. A large volume of gas would he required. If the sewage contained 
1 per cent, of organic matter, 1 gallon would contain about 50 grammes, 
which would require about 10 grms. of "nascent" oxygen, or 30 grms. 
of ozone. Assuming the ozonised oxygen to contain 5 per cent, of 
ozone, 300 litres of ozonised oxygen would be required to disinfect 
1 gallon of sewage if the ozone all acted. But as, owing to difiusion, 
it is reasonable to assume that only part of the ozone would act, a very 
much larger amount of gas would be required to effect the purpose. 

3. It comes in competition %mth chlorine, which is more soluble, and 
therefore, more rapidly absorbed, and as it can be easily produced in a 
pure state (100 per cent, as against 5 per cent.), a quicker and more 
certain action from its use can l)e relied on. 

4. Tlie question of cost. "With equal efficiency, this would of course 

* Jowm. Sot. Chem. Industry, 1891, p. 720 ; Report of State B. of Health, 
Mass., U.a.A., p. 783 ; Proc. Inst, Civ. Engineers, 105, vol. Hi., p. 9. 
t Brin, October, 1881, patent void. 



J. T. Wood* converts sewage or other polluted liquid into spray by 
the action of a blast of *' air, oxygen, ozone, or other suitable gas " 
under pressure, by which it take^ up more than it would under 
ordinary circumstances. "Auy chemical precipitant" is projected 
into the spray, the sewage allowed to settle in tanks, and the clear 
liquid further purified by passing it over "oxidising stairs," the 
" risers " being provided with openings which communicate with tubes 
containing the ozonised air under pressure. Modifications of the 
air-blast are described applicable to filter-beds and the weirs of rivers. 
It is to be feared that the expense would be prohibitive. It does not 
seem to have been tried on the large scale. 

In the dry state, ozone has very little action on micro-organisms, 
but when moist is a very powerful bactericide. Ohlmuller f found 
that when bubbled through water in which bacteria were suspended, 
the strength being 15 milligrammes of ozone in 1 litre of air, anthrax 
spores (the most difiScult of all to destroy) were killed in ten minutes 
by not less than 90 milligrammes of ozone to the litre of water, anthrax 
bacilli by 58 mgms., typhoid by 19*5 mgms., and cholera by about 
18 mgms. A most important factor to be taken into account is that, 
when the water contains organic matter the action is much diminished, 
since the ozone attacks the unorganised matters first, and in so doing 
is destroyed. It must not be forgotten that the oxidation of organic 
matter purifies the water, and would apparently render it less liable ta 
subsequent infection, as the pabulum for the bacteria is diminished. 
Recent researches seem to show, however, that the pathogenic 
organisms actually multiply with much greater rapidity in pure waters 
than in ordinary river waters, although they subsequently decline 
equally rapidly. No process, therefore, that is simply founded on 
diminishing the organic matter in water, can be regarded as trust- 

It will be noticed from the above experiments that a very large 
volume of air must be driven through the liquid, amounting for 
anthrax spores to six times the volume of the water treated before 
sterilisation can be assured. Since no materials, except glass or stone- 
ware, resist the action of ozone, metals, wood, grease, indiarubber, &c., 
must be avoided in the construction of any apparatus employed. 

In generating ozone, the temperature is of importance. At 6° C. 
no ozone appears to be formed ; from this point the yield increases up 
to 24° C, then declines. 

When permanganates are treated with strong sulphuric acid, ozone 
is evolved. Meyer J makes an intimate mixture of barium perman- 

* Patent No. 22,747, 1891. t Arheitena. d. Kais. Gemnd.y 1892, vol, viii., p. 229. 
t Patent No. 16,463, 1888. 


ganate and sodium bisulphate in the proportion of 25 per cent, of the 
foi-raer and 10 per cent, of the latter. " If sufficient water be added 
to sucli a mixture so as to form a thick syrup, ozonised oxygen will he 

The cheapest way of obtaining ozonised air is by means of the 
silent electric discharge. A convenient method, however, for gene- 
rating it in small quantities is by means of moist phosphorus, keeping 
it constantly cool to avoid inflammation. 

A. Riche first proposed moistening the phosphorus with a solution 
of potassium bichromate and sulphuric acid, instead of water, and 
aspirating or, better, driving a slow current of air over it. He 
mentions a form of " kerite " as the best material for the tubes. 

Kattenhoy* places the sticks of phosphorus in glass-capped holders, 
just projecting from a solution of potassium permanganate in 10 per 
cent. suli>huric acid. The whole is enclosed under a bell-jar pierced 
with holes for the outlet of ozonised air, with a locked cover to prevent 
tampering. There is a funnel to add more liquid when required, and 
a sliding glass-rod support to adjust the level of the phosphorus. Such 
an apparatus might be of service for inlet ventilators, but its use 
would not be advisable in a room, since even a trace of ozone in §xcess 
would be irritating to the lungs. 

At Berlin the electrical manufacture of ozone on a large scale has 
been attempted for sanitary purposes. 

Andreoli's apparatus, at present in operation at Allen ik Hanbury's 
works at Bethnal Green, is based upon the silent discharge of electri- 
city from points in the well-known " brush " or glow, as distinguished 
from the spark. The former generates ozone, whereas the latter, by 
its high temperature, destroys it. A large number of serrated strips of 
tinned iron are arranged parallel to one another so as to form gratings 
on opposite sides of plates of glass. The gratings are connected with 
the poles of a dynamo-transformer, giving a high-tension current of 
10,000 volts. The apparatus gives a larger surface and a more 
uniform distribution of the current than other ozonisers of the 
Siemens' type. Air is driven by a fan through a cotton wool tilter at 
a rate of 160 cubic feet per minute, then, after cooling, and drying by 
sulphuric acid on pumice, it passes over the gratings by which about 
6 per cent, is calculated to be ozonised. 

The same inventor has smaller open ozonisers intended for domestic 
use, which can be worked by an electric supply current.f 

Dr. Forster, of Berlin, proposes the supply of a small quantity of 
ozone to the air of towns, stating that many epidemics, such as 
influenza, arise at times when the atmospheric ozone is at its 
• Patent No. 24,709, 1S93. f Industries and Iron, Aug. 18, 1893. 


lowest, and that an artificial supply might prevent or modify the 

Many years ago an attempt was made to supplement the advantages 
to be derived from a winter's sojourn in the High Alps by supplying 
the air of the hotel at Maloja with ozone from powerful induction 
coils, but it seems that no special benefit from its use was felt by the 
patients. Dr. Hassall's experience at his sanatorium at San Kemo 
was also disappointing. There are, however, many cases in which it 
is stated to have proved V^eneficial in phthisis, and late experiments in 
the Berlin hospitals have shown results in its favour. 

Peroxide of Hydrogen, H.^O^, is prepared by acting on a peroxide of 
an alkaline earth by an acid, e.g. : — 

BaOa + CO2 + H2O = BaCOg + HoOj 
BaOj + H2SO4 (dilute) = BaS04 + H2O2 

It is a syrupy, inodorous, and neutral liquid, which easily decom- 
poses into water and nascent oxygen, hence bleaches and acts as a 
powerful oxidising agent. In the dilute state it is neither irritant 
nor poisonous. Its instability is lessened by the addition of a small 
quantity of acid. Two forms occur in commerce — " ten volumes" and 
" twenty volumes" — indicating nominally the number of times its 
volume of oxygen it gives off when treated with peroxide of manganese, 
according to the following equation — 

H2O2 = H2O + 

The commercial peroxide should always be tested as its quality is 
often very inferior.* 

When an electric current is passed through water, whether the 
gases oxygen and hydrogen be evolved, or whether the current be so 
weak that the oxygen remains dissolved, the latter is ozonised, and 
the water acquires oxidising properties, and behaves as if it contained 
peroxide of hydrogen. Such a solution has been patented, but the 
product is too weak to be of use. " Ozonised water " has been intro- 
duced under the name of " antibacterikon." 

Peroxide of hydrogen is probably present in the "Hermite" 
solution already described (p. 67). 

As a disinfectant hydrogen peroxide would be excellent if it were 
quicker in its action. Angus Smith in 1869 called it " the disin- 
fectant of the future." It oxidises such bodies as sulphuretted 
hydrogen readily, it has no smell of its own, and is not poisonous. 
Metals and fabrics are not attacked ; it has not, like permanganate, 
the tendency to act on inert matter, though it possesses the true 
characters of a disinfectant. Its action has been recently studied 

* For a simple method of measuring the gas evolved, see Methods of Analysis, 
Chap. XV. 


in some detail by MM. Paul Bert and Reynard.* They found that 
all fermentations caused by bacteria are at once stopped by peroxide 
of hydrogen, and the ferment killed; while no effect is produced on 
enzymes, such as diastase and those of saliva, gastric juice, and the 
pancreas. When fibrin has been dissolved in dilute hydrochloric acid, 
or changed into fibrin-peptone by artificial digestion, hydrogen per- 
oxide is without action on it. It has no eflfect on foods, like albumen, 
casein, milk, eggs, fats, sugar, starch, and juice of fruits. So that 
it is practically one of the few disinfectants which have no effect on 
digestion, and yet prevent the interfering action of organisms. 

Van Ti'ompt asserted that 1 part of peroxide of hydrogen in 
10,000 of polluted water, when shaken up and allowed to stand for 
twenty -four hours, was usually sufl&cient to sterilise a water. 
Altehoefer, however, found, + that to ensure sterility, it was advisable 
to use larger quantities, namely 1 part in 1,000 parts of water. 
" Experiments made with waters purposely infected with cholera and 
typhoid bacilli, showed that both these were destroyed in twenty- 
four hours by 1 per niille of hydrogen peroxide." Altehoefer, 
beyond a slight taste, which disappeared after twenty-four hours, 
found no detriment to the water for drinking or domestic purposes, 
and recommends its application for household use as a protective 
measure during any epidemics of typhoid fever or cholera. He 
suggests that 10 c.c. of a 10 per cent, solution should be added to a 
litre of water, or 70 grms. to the gallon. Traugott also testifies to 
its innocuous character, even when swallowed in large doses. § 

Guttmann injected peroxide of hydrogen hypodermically, but the 
oxygen was liberated as gas in the circulation, and the animals died 
of asphyxia. 

Miquel places it at the head of his list of antiseptics, making 
0-05 grm. sufficient to sterilise 1 litre of beef tea, as against 007 grm. 
of mercuric chloride. Later observers give it much lower potency, 
averaging about O'l per cent. 

The class of oxides known as peroxides, which contain more oxygen 
than the ordinary bases, resemble hydrogen peroxide, and are capable 
of the following reactions : — 

1. "When heated they give off oxygen — 

H2O2 = H2O + O. 
BaOj = BaO + O. 

2. With hydrochloric acid they generate chlorine — 

MnOj + 4HCI = MnClj + 2H,0 H- CI,. 

* Berlin Ber., vol. xv., p. 1,585. t Apoth. Ze'Uung, 1890, p. 485. 

tCentr.f. Bakteriol, 1890, vol. viii, p. 129. §See under Light, p. 10. 


3. With sulphuric acid they give (ozonised) oxygen or hydrogen 
peroxide — 

(i.) Strong acid: BaOa + H2SO4 = BaSOi + HgO + O. 
(ii.) Dilute acid : BaOo -f H2SO4 = BaSO^ + HoOa- 

Many of the peroxides have consequently received attention in the 
search for disinfectants. 

Sodium Peroxide, Na^Og, manufactured by the Aluminium Company 
at Oldbury, near Manchester, is a white powder which on exposure to 
air becomes damp and spoils, therefore must be kept in tightly closed 
tins. It is easily soluble in water, and acts like a solution of hydro- 
gen peroxide plus caustic soda. 

NaoOa + 2H2O = 2NaOH + HjOa. 

If acid be added to the powder, hydrogen dioxide or ozonised oxy- 
gen is produced, according as the acid is weak or strong. 

Jacobsen* mixes "dioxide of barium, strontium, or calcium with 
any desired metallic salt." Peroxide of barium is cheaply obtained in 
Erin's oxygen process. Carbonic acid of the air, in the presence of 
. water, causes it to yield peroxide of hydrogen. 

Schone is of opinion that peroxide of hydrogen exists naturally in 
the atmosphere and in waters. The point is not yet proved, f 

Dr. Richardson proposes to saturate peroxide of hydrogen with 
iodine (very little dissolves), then to add 2i per cent, of sea salt, and 
to use the mixture as an antiseptic spray in an "atomiser." 

Peroxide of hydrogen and ozone with other products are formed by 
the slow oxidation of essential oils in presence of air and water, 
especially if warmed. Such a product, consisting of turpentine oil, 
water, and air, was patented:}: under the name of "Sanitas;" more 
, recently § resin, resin oil, camphor, and thymol have been added. 
These antiseptics would supplement the action of the peroxide of 
hydrogen or ozone that might be present (see p. 215). 

J. Y. Johnson || causes air or oxygen to pass through a mixture of 
9 parts of water and 1 part of spirit of turpentine, maintained at the 
ordinary temperature. "When sufficiently saturated with ozone, it is 
used as a disinfectant for washing wounds. 

A convenient test for the presence of peroxide of hydrogen is to add 
a drop of potassium bichromate solution and a little dilute sulphuric 
acid to the disinfectant. A blue colour is produced on shaking 
with ether. " Sanitas " answers to this test when freshly prepared. 

* Patent No. 1,711, 1882. t Chem. News, April 27, 1894. 

t Patent No. 274, 1878. § Patent No. 1,172, 1882. 

II Patent No. 14,864, 1884. 



Nitric Acid, HNO3, when pure is colourless, and has a not very- 
powerful nitrous odour, as compared with the lower oxides which give 
the colour and suffocating sraell to the impure acid. Its specific 
gravity is 1-52, and boiling point 113° C. As one of the strongest of 
oxidising agents, it is actively disinfectant, but also very corrosive and 
poisonous. It oxidises organic matters to such compounds as oxalic 
acid, and then finally to carbonic acid and water, being itself reduced 
successively to the lower oxides of nitrogen, which in turn combine 
with the organic substances to form nitro-derivatives like pyroxylin, 
nitroglycerin, and picric acid. The latter class of bodies, when soluble 
or volatile, are themselves poisonous and disinfectant. 

Nearly all metals are attacked by nitric acid, giving nitrates and 
oxides of nitrogen, for instance — 

3Cu + 8HNO3 = 3Cu(N03)2 + 2N0 + 4H2O. 

If sulphuric acid be added at the same time, the whole of the nitric 
a,cid is driven off as nitric oxide. 

Nitric acid vapours are white, and are much less injurious than the 
red vapours of the oxides. Nitric oxide, NO, is colourless, but turns 
red in air, forming higher oxides according to the quantity of oxygen ; 
all these are exceedingly poisonous, since they form compounds with 
the colouring matter of the blood. They may be described as irritant, 
depressant, and narcotic. 

Dr. Calvert (1872) ranks the antiseptic power of nitric acid in dilute 
solution as about equal to that of hydrochloric. 

Nitric acid fumigation was introduced in 1780 by Dr. J. C. Smith 
for a violent outbreak of typhoid in the British Fleet. For his success 
he was voted £5,000. On a large iron sand-bath over a brazier were 
placed a number of stoneware capsules, each containing 12 grammes of 
oil of vitriol ; when hot enough, powdered nitre was added little by 
little. On stirring with a glass rod, the nitric vapours were evolved 
in abundance as a thick white mist. The apparatus was carried about 
among the patients, who unfortunately were affected with violent 
coughing. Severe bronchial irritation followed, and some destructive 
action of the surroundings. 350 grammes of nitre in 27 capsules were 
used for the one hospital ship. The fumigation was daily repeated 
for a week. The heat should not be too great, and the disengagement 
should be gradual. 

The horrible stench at once disappeared, and the epidemic was con- 
quered in three weeks, the deaths falling on the first day from 31 
to 9, and then steadily to the end.* 

* Vallin, IMiiin/eclanlti, 1882, p 263. 


Nitrogen Trioxide, NjOg, is a red gas of suffocating odour, combining 
with water to form nitrous acid, HNOq. Girard and Pabst * describe 
NoOg as a very strong disinfectant in doses so weak as to be not 
dangerous, the odour being rather a^romatic and etherial. Unfortun- 
ately, nitrogen trioxide is a very unstable substance, and is almost 
always accompanied by the other oxides of nitrogen. The above- 
named authors patented the use of "chamber-crystals," or nitro- 
sulphuric acid, in a tower filled with coke. The putrid emanations 
from closets or sewers are caused to pass up this tower, and, being 
moist, they dilute and decompose the chamber-crystals, which evolve 

this gas — 

2S02(X02)OH + H2O = 2H2SO4 + N2O3. 

The gases on passing out are quite innocuous, f 

HaddanJ mixes an aqueous solution of sodium or other soluble 
nitrite with sulphuric acid (5 parts of acid in 1,000 parts of water), 
and adds the resulting dilute nitrous acid to sewage. The nitrogen 
trioxide transfers oxygen to the organic matter, and is re-oxidised by 
the air, so acting in the well-known way as a carrier from the atmo- 
sphere to the sewage, so that " all organisms are destroyed." Although 
theoretically this action enables a small quantity of oxide of nitrogen 
to do an tinlimited amount of work, yet in practice the disinfection by 
nitrous compounds has proved expensive, and has no advantages over 
other methods. 

Nitrites are somewhat antiseptic ; internally they are dangerous 
(Lauder Brunton). 

Nitric Peroxide, NO^, is a red irritant gas, easily condensed to a 
brown liquid. If it were desirable, the latter would be the most con- 
venient form for use, and could be. obtained in sealed tubes or syphons 
like sulphurous acid. It is made by heating nitrate of lead. 
Pb(N03)2 = PbO + 2NO2 + O. 

Guyton de Morveau, in his classical work, found that this gas 
was a feeble disinfectant, but irrespirable and dangerous. Payen § 
places NO2 in the front rank among disinfectants. He uses for a space 
of 40 cubic metres, 1,500 grammes of nitric acid, 2,000 of water, and 300 
of copper turnings tied up in a thick paper bag to moderate the action. 
Even thus it is liable to become too violent, and much of the nitric 
acid is wasted as nitrous oxide or even nitrogen. Three-fourths of the 
nitric acid remain behind as cupric nitrate, and this, of course, would 
act slowly as a liquid absorbent. Payen's process was carried out in 
sealed rooms during the siege of Paris. He allowed forty-eight hours 
for complete disinfection. The cost is obviously very high. 

♦ Disinf. de« Latrines, 1881. t No. 18,486, 1881. 

t Patent No. 4,714, 1885. § Complex licndus, March 6, 1871. 


Notter* says that an attnospliere containing 035 per cent, of nitro- 
gen peroxide killed all bacteria in putrid beef tea in forty-eight hours. 

Sternberg t states that 1 per cent, of nitrogen peroxide in air will 
sterilise vaccine in six hours, while J per cent, was not disinfectant. 
He makes this power to be identical with those of sulphurous acid and 
chlorine. There is, therefore, no apparent benefit resulting from its 
\ise. Severe bronchitis and sevei'al deaths from poisoning have been 
recorded as resulting from breathing this gas {Angus Smith). 

Nitrous Ether (ethyl nitrite), C.^HjNOg, was tried both as an anti- 
septic and disinfectant by Peyrusson and by Guillaumet in 1881. The 
former considered that it disengaged ozone. + Vallin's experiments' 
prove it useless. § Miquel states that in fifteen to twenty days at 
20° C. it was absolutely incapable of destroying the vitality of bacteria,|| 

Nitrobenzene will be alluded to among organic compounds. 

In conclusion, the opinion is irresistible that nitric disinfection i& 
the worst of all methods, and under no circumstances should be 
allowed. Fortunately the patents are few. 


The abundance of this element in volcanic districts, and the charac- 
teristic odour of its compounds, sulphurous acid and sulphuretted 
hydrogen, seem to account for the fact that sulphur and its compounds 
have had the earliest reputation as antiseptics and disinfectants. 

In Fawkes' translation of Theocritus we read — 

'* Next with pure sulphur purge the house and bring 
The purest water from the freshest spring, 
This mixed with salt and with green olive crown'd 
Will cleanse the late contaminated ground." 

Sulphurous acid is still the official disinfectant ; its ease of applica- 
tion and cheapness being its principal merits. The element itself, in 
the form of '• flowers," is dusted on plants to kill aphides, and is 
extensively used for vines against Oidium, as well as for hops and 
seeds. Here it, undoubtedly, by slow oxidation, gives off sulphurous 
acid. Mixed with soap it generates an alkaline sulphide, and this in 
turn, by the action of the carbonic acid of the atmosphere, liberates 
sulphuretted hydrogen. Given internally, as " flowers " or " milk " 
of sulphur, it also creates sulphuretted hydrogen in the body, evolved 
subsequently by the skin, and killing or enfeebling such parasites and 
micro-organisms as cause many of the skin diseases. So " brimstone 
and treacle," and the modern " sulphur lozenges," reach their reputa- 

* Journ. Med. Science, Dublin, 1881, p. 508. 
t Nat. Board of II., Washington, 1881. ::: Comptes Rendus, 1881, p. 492. 

§ Desin/ectaiits, p. 214. li Org. de I'AtmospIt., p. 291. 


liion. In ointments also it is absorbed. The xitility is undoubted, 
though the action is slow. To quicken it, it must be combined with 
oxygen or hydrogen, so as to be soluble in water, and diffusible in 

Sulphuretted Hydrogen, HgS. — This gas is slightly heavier than air, 
soluble in water (3 volumes dissolve in 1 of water at 15'5° C), slightly 
-acid, and blackens silver and some other metals. Its odour is well 
known, and it acts as a depressant poison, reducing the blood colouring 
matter of animals to methsemoglobin, which is incapable of carrying 
out respiration. It is, therefore, not suitable for an aerial disinfectant. 
Since it destroys most bacteria, especially that of tubercle, Dr. 
Bergeon* has employed it with marked success, by anal injections of 
the saturated aqueous solution, for pulmonary phthisis, itc. Niepce 
inhales the gas, but the former plan seems better, as not so toxic, 
since Claude Bernard has established the fact that some gases, which 
^re poisonous when passed into the arterial system, become innocuous 
in the venous-per-intestinal absorption. Breathing continually small 
■quantities of sulphuretted hydrogen is without doubt injurious to 
health, producing anaemia and low vitality. 

The soluble sulphides of the alkalies and alkaline earths have similar 
properties, giving off the gas on exposure to air. Hence probably the 
use of sulphur springs for cutaneous affections. 

Dr. Percy F. Frankland found that sulphuretted hydrogen was 
■detrimental to the vitality of Bacillus pyocyaneus, Koch's bacillus, and 
Spirillum Finkleri, the ones specially selected as typical ; also to the 
majority of microbes, a few, however, thriving on it.f It must be 
remembered that sulphuretted hydrogen is itself one of the products 
of putrefaction, one class of organisms, represented by Beggiatoa (the 
" sewage fungus "), not only reducing the sulphates to sulphides, but 
also converting the latter into solid, and often crystalline, sulphur 
within their protoplasm. To such, which are not the more dangerous 
ones, sulphuretted hydrogen would do no harm. 

This gas is a reducing agent by means of its hydrogen, sulphur 
being liberated. It is destroyed by all oxidising agents, eventually 
producing sulphuric acid. The action of chlorine, bromine, and iodine 
upon it has already been mentioned (p. 58). Lime and alkalies, and 
salts of the heavy metals, except those of aluminium, absorb it, forming 
sulphides. Ordinary acids do not remove it beyond the extent of its 
solubility in water. Sulphurous acid decomposes it. 
2H2S + SO2 = 2H2O + 3S. 

In sewer gas ammonium sulphide, as fetid and poisonous as sul- 
phuretted hydrogen itself, always exists, and seems to be one of the 

* BriU Med. Joum., Dec. 18, ISSG. t Proc. Roy. Soc, vol. xlv., p. 292. 


chief narcotic agents in causing suffocation in sewers. If paper moist- 
ened witli lead acetate be discoloured by any emanations, sewer gas is 
indicated, unless it be derived from a chemical or gas works. The 
absence of sulphuretted hydrogen or of smell is, however, no proof of 
efficient disinfection. Many so-called disinfectants, moreover, merely 
mask one smell by creating another. Even the presence of excess, as 
shown by the odour of the disinfectant, does not prove efficiency ; 
there must beyond this be a sufficient percentage present, ascertainable 
only by experiment and calculation. 

Sulphur Dioxide or sulphurous anhydride, SO2, is a colourless gas of 
specific gravity 32 (air = 14*45), with the well-known odour of burning 
sulphur. One litre weighs nearly 3 grammes. It is obtained by 
burning sulphur or a sulphide in air — 

S -)- O2 = SOj. 

One kilogramme of sulphur gives 700 litres of the gas. 

It is irrespirable, producing violent coughing and suffijcation. 
About 5 per cent, in air has produced fatal results, causing acute 
catarrh, acid eructations, anorexia, irregularity of the bowels, and 
permanently impaired digestion (Hirt, Eulenherg, »fec.), but i per cent, 
can be endured for a length of time. A wet towel moistened with 
washing soda enables a larger amount to be faced. 

One litre of water at ordinary temperatures dissolves 50 litres, or 

145 grammes, producing an acid liquid containing the unstable 


SOo + H2O = H2SO3. 

This liquid smells strongly of the gas, as, gradually at ordinary 
temperatures and rapidly on heating, it decomposes again into sulphur 
dioxide and water. Hence it rapidly loses its strength unless well 
stoppered. (It only slowly attacks corks, so that it can be kept in a 
corked bottle.) In the anhydrous state it is not disinfectant; on 
adding water it becomes active; hence the term "sulphurous acid" 
will be used throughout for this agent, as more familiar and accurate. 
It acts in four ways : — 

1. As an acid it absorbs ammonia, compound ammonias, and organic 
bases like "ptomaines" and the products of growth of pathogenic 
organisms. The salts so formed (sulphites) are much less injurious. 
It has this property in common with other acids. 

2. It decomposes sulphides and sulphuretted hydrogen, as above 

3. It reduces organic matters, or combines with them, to form com- 
pounds which are in most cases inert. This explains its bleaching 
action on vegetable colours, as the compounds] formed are nearly 


colourless. But the action is evanescent, as on exposure to air it is 
oxidised to sulphuric acid, and the colour often reappears. 

4. As a })oison it kills living organisms. 

The gas can be easily condensed to a colourless liquid by pressure, 
and preserved in strong metal vessels. About 3 atmospheres (45 lbs. 
on the square inch) is sufficient. Messrs. Boake «fe Co.* have intro- 
duced commercially this liquefied gas, and as it is attainable in any 
quantity at a cheap rate, it is much more convenient to employ than 
sulphur. The vessels are opened by a lever attached to a screw. The 
gas will flow steadily for forty hours, a single syphon evolving 500 
litres of gas, equal to the amount obtained from about 1^ lbs. of 
sulphur. They also make hermetically sealed tins which are sufficient 
for the disinfection of a small room. The gas is obtained by cutting 
with a knife the soft metal pipe attached to the tin. 

Whenever the anhydrous gas is used, the rooms must be sprayed or 
steamed to provide the necessary moisture to form the acid H2SO3. 

Sponges are frequently disinfected and bleached by first immersing 
them in a bath of hyposulphite of soda (| lb. to 1 gallon water), and 
then adding ^ lb. of oxalic acid in crystals ; sulphurous acid is liberated 
and sulphur deposited in the pores of the sponges. After washing 
with boiled water, they can be kept in a weak carbolic acid solution. 

The Governments of England, United States, Belgium, France, 
Austria, Sweden, and some others prescribe fumigation by burning 
sulphur for infected rooms. Hence, as Arnould says, it is the " official 
disinfectant par excellence." Germany, amongst European nations, 
however, does not recommend it officially. It is difficult to keep it 
alight, and various devices have been introduced to remedy this defect. 
"When sulphur is used, instead of the compressed oxide, Corfield and 
Louis Parkes burn it in an iron vessel with a little spirit. Nicholls 
and Billyen, and also Vallin use 8 parts of flowers of sulphur, 
2 or 3 of nitre, and 2 or 3 of bran or liquorice powder. This would 
give a deflagration, would retain much of the sulphur in the residue as 
sulphate, and would result in rather too rapid an evolution, so that 
the inevitable leakage would be greater. Another plan is to place it 
on an iron tray and throw a shovelful of red-hot coals on it. When 
this plan is adopted, there is usually a residue of unburnt sulphur left. 
A chafing-dish of coals, properly protected, with an iron tray over it, 
and lumps of sulphur distributed gives better results. Even with 
these devices, it is almost impossible to keep up a combustion suffi- 
ciently long, hence the liquefied gas, excluding, as it does, the risk of 
fire, is much to be preferred. 

J. Robertson! has devised a portable iron stove provided with an 
• Patent No. 12,238, 1885. t Patent No. 10,129, 1891. 


evaporating or burning pan in which is placed the chemical to be 
evaporated or burnt, and connected with a fan, by means of which air 
is drawn through a hose or flue to the place where they are to be 

J. H. Johnson * lias a chamber for sulphuring clothes, rags, &c. 

Kingzett's sulphur candles are made in the form of a night-light, 
and are placed in a water-jacket as a precaution against fire. They 
are made of sulphur with a "powerful oxidising agent," and a wick. 
These are arranged to burn two hours. They ai"e very convenient if 
they yield sufficient of the gas. The cost is moderate. 

Seabury's sulphur candles t also burn two hours, and differ from the 
above in having a large compound wick. Morse and Bourne's patent]; 
principally affects the shape of these candles. § 

Neutral sulphites, such as sodium sulphite, Ka^SOg, are not decom- 
posed like hypochlorites by the carbonic acid of the air, hence they 
neither smell of nor give off sulphur dioxide. Both the acid and its 
salts absorb oxygen from the air, changing to sulphates, and therefore 
they act as i*educing agents. The acid or bisulphites of sodium, 
calcium, and magnesium are much used for preserving provisions ; 
they slowly evolve sulphurous acid gas. The sulphites, as distinguished 
from the free acid, are poor disinfectants, but a large number of patents 
have been taken out for their use either alone or in mixtures. Most 
of these patents are of doubtful utility. 

A bisulphate mixed with a bisulphite would be a convenient form, 
which would evolve sulphurous acid ou being moistened, thus — 
NaHSOi + NaHSOs ^ Na2S04 + HjO + SOg. 

R. Y. Tuson|| suggested the use of various metallic sulphites, andU 
proposed to employ a saturated solution of sulphurous acid in liquid 
phenol. G. Purvis ** charges sewage with sulphurous acid, then neu- 
tralises with lime and adds other substances in the proportion per 
gallon of 7*5 grains sulphurous acid, 7*5 grains lime, 4 grains aluminium 
sulphate, and 1 to 5 grains charcoal, ft 

M'Dougal and Meldrum H state that "the prejudicial and offensive 
products of the .decomposition of sewage matter are mainly compounds 
of sulphur and phosphorus with hydrogen or alkalies. Sulphurous 
acid decomposes these, forming thiosulphates, hypophosphites, «fec. 
This is the base of the process. The gas is generated by burning 
sulphur, pyrites or the spent oxide of gas works, and passed in until 
the liquid is acid." 

* Patent No. 2,567, 1883. t Patent No. 6,407. 1893. :;: No. 18,434," 1891. 
§ Journ. Soc. CJiem. Industry, Feb. 29, 1892. I! Patent No. 8,645, 1879. 

IT Patent No. 1,081, 1879. ** Patent No. 18,286, 1891. 

.tt See also Van Alsing, Patent No. 2,644, 1878. tt Patent No. 2,846, 1891. 


Fryer and Alliott* place sewage pails in an air-tight vessel, exhaust 
the air, then let in steam, hot air, sulphurous acid, chlorine, phenol 
vapour, or other volatile disinfectant. The action is thus more con- 
centrated. The process is also staled to be suitable for the disinfection 
of wearing apparel, bedding, «fec. There are a number of other patents 
of less importance. 

Thiocamf (Prof. E. Reynolds) is a liquid formed by leading sulphur- 
ous acid into a bottle containing camphor. The resulting product 
contains 30 to 35 per cent, of sulphur dioxide. Various other disinfect- 
ants (not oxidisers) can be mixed with it. On exposure to air it gives 
off its sulphurous acid and leaves a white antiseptic residue of, pre- 
sumably, camphor. A 6-ounce bottle evolves about 20 litres ot gas. 
It was recommended by the Disinfecting Committee of the House of 

The official directions for sulj)hur fumigation are as follow ; — British 
Local Government Board : 1| lbs. of sulphur burnt over a small fire, 
in a carefully sealed room, for six hours or more. (This would give 
1*76 per cent, of sulphurous acid in the air.) The wall paper is then 
to be stripped off and burnt, and the ceiling and floors thoroughly 
washed, &c. Recent suggestions of the Society of Medical Officers of 
Health add that bedding and clothes should be spread out on lines, 
that the sulphur should be burnt over a pail of water to supply 
moisture, and that the time should be twenty-four hours. In Belgium 
the disinfection is purely domestic, except in the case of persons. The 
quantity is 20 to 30 grammes of sulphur per cubic metre, or 2 to 3 per 
cent. In Paris 20 grammes is used per cubic metre for forty-eight 
hours. In Berlin sulphur disinfeclion is not much employed. In 
Austria and Sweden the official regulations advise the use of sulphurous 
acid. The American Committee on Disinfection enjoin "exposure for 
twelve hours to an atmosphere containing at least 4 per cent, of sul- 
phurous acid in presence of moisture = 1^ to 2 kilos, of sulphur for 
every 28 cubic metres " — an ordinarily sized room. 

For ships arriving in the Mississippi from infected ports, the cargo 
is sprayed with corrosive sublimate solution, but sulphur fumigation 
is used for the hold. A battery of eighteen furnaces contained in a 
specially constructed tug is used for heatiilg the sulphur, and the gas 
mixed with air is forced into the hold at the rate of 180,000 cubic feet 
per hour by means of a fan. 100 lbs. to lj700 lbs. sulphur is used for 
each vessel. 

There has been a great conflict of opinion on the value of sul- 
phurous acid disinfection. Vallin f pronounced it perfect, Arnould J 
says that " sulphuric acid, even in the almost inapplicable dose of 

• Patent No. 1,565> 1877. t Traiti des Disinfectants. X Hygiene, 1889, p. 501. 


10 per cent., is an uncertain means of destroying spores ; even mois- 
ture does not ensure success." Dr. Cassedebat, after a research at the 
Marseilles School of Medicine,* remarks " even in the highest doses 
it is too inconstant to be recognised in the disinfection of virus." 
Savarellif condemns it. Miquel could not kill germs in twenty 
days.:^ Sternberg's experiments § were unfavourable — "it requires 
special conditions rather than abundance." Dr. A. J. Martin II says 
" its efficacy is contestible, without counting its public nuisance." 

Dujardin-Beaumetz,1I who studied the behaviour of this gas with 
Pasteur and Roux, found that 20 grammes of sulphur, as used in the 
official French fumigation, did not kill JBacillus anthracis, though it 
sterilised tubes of vaccine.** Since Wolffhiigel's experimentsff in 1881, 
sulphurous acid has quite lost its reputation in Germany. Kochijt 
obtained similar results ; he spread the spores about in a room where 
sulphur was burnt, or laid them on boards which were then washed or 
sprayed with a solution of sulphurous acid and tested by transference 
to culture solutions or by inoculation. §§ 

Dubief and Bruhl |j|l state that " sulphurous acid has the most de- 
structive effect on aerial microbes, especially moist, acting mainly on 
the spores of bacteria, and when pure and acting for a long period, it. 
may prove fatal to dry germs." 

M. d'Abaddee states that of the Sicilian labourers engaged in 
sulphur works only 8 or 9 per cent, suffer from intermittent fever as- 
against 90 per cent, of those not so occupied. The sulphur works in 
the marshy plain of Catania protect the people in the vicinity from an 
evil that causes other villages to be deserted.llli This tends to prove- 
that sulphurous acid is strongly antagonistic to malaria; 

Dr. P. Frankland *** found that it killed several pathogenic 
organisms. Baumann destroyed B. tuberculosis with it, and has cured 
several cases of early phthisis by burning sulphur. 

Klein has furnished the key to these discrepancies by showing 
that although " most pathogenic microbes do not thrive in an acid 
medium, some putrefactive and zymogenic organisms can thrive well 
in acid — e.g., Bacillus subiilis, Micrococcus urece in acid urine, Jcc." ttt 

• Bevue de Hygiene, 1891. t Giom. Soc. Ital. d'llyg., 1890. 

X Les Org. vivanta de VAtmc^ph., 1883, p. 289, et seq. 

%^fed. News of Philadelphia, March 28, 18S5. 

II Soc. de Med. Publique, 1892, 1 Bull, de VAcad. de 3fed.y Sept. 9, 1884. 
*• See Rochard's Encydopicdie d' Hygiene, vol. v., 1893. 
HMittheil. a. d. Kais. Gesundh., vol. i., p. 188. :::::: Ibid., p. 234. 

§§ Wolflfhiigel and Proskauer, Chem. Centralblalt, vol. xiii., p. 334. 

nil Comptes Rendus, 1889. HIT Journ. Soc. Chem. Ind., voL L, p. 51a» 

••• Proc. Boy. Soc, vol. xlv., p. 292. 
t++ Micro-organisms and Diseases, 1886, p. 258. 


Therefore, sulphur disinfection, though generally successful, may 
sometimes fail. Wynter Blyth is also of the same opinion. 

M. Thoinot sums up thus in hiH^Beport to tlie Committee of Public 
Hygiene o/tJie Seine, 1891 — "The disinfection by sulphurous acid is 
only a practice of waiting, but it is a good practice, and ought not to 
be despised." * 

It was objected to the halogens that they were apt to corrode the 
fabrics submitted to them. The same thing is liable to happen with 
sulphurous acid, as its oxidation in air leaves behind sulphuric acid, 
which is not volatile. 

Sulphurous acid and the bisulphites are widely used for preserving 
food. They act (1) by absorbing oxygen, (2) by suspending the growth 
■of moulds and ferments, like those of the vinous, acetous, lactic, and 
butyric fermentations. Tn canned goods they are objectionable, as 
they dissolve tin and lead from the metallic envelope. Dr. Pfeiffer, of 
Munich, asserts that large quantities of sulphurous acid and bisul- 
phites in beer, itc, are undoubtedly injurious to health. The 
maximum allowed for wine and beer in Austria is 8 milligrammes per 
litre, on the basis of the opinion of the Medical Faculty, March 19, 
1887. But at least 40 milligrammes per litre might be allow'ed 
without injury.! Nessler says that 2*7 to 5*4 milligrammes per litre 
is sufficient to prevent secondary clianges in wine, whilst 22 milli- 
grammes suppresses fermentation for fully twenty -eight days. 

Calcium bisulphite and sulphurous acid in more than a minute 
trace spoil the flavour of most foods, giving a flatness and metallic 
taste which is distinctly perceptible. These salts are extensively used 
in beer (in finings), in wines and fruit syrups to absorb oxygen, and to 
hinder secondary fermentations. They are the least noxious of pre- 
parations of this kind. L. Pfeiffer, in a paper on the poisonous action 
■of sulphurous acid and its salts, J states that sulphites are sometimes 
added to wine in such quantities as to produce injurious results. Out 
of eighty specimens of wines examined by Kammerer, sixteen contained 
sulphites in quantities ranging from -017 to '093 gramme per litre. 
List detected sulphites in a large number of French wines, the amount 
varying from '009 to '135 gramme per litre. Their presence in wines 
is likely to cause irritation, if the quantity of acid exceeds 0*08 gramme 
per litre. 

Johnson and Saladin § propose an apparatus for cleansing grain, 

* See also Klein, Lawes and Lingard in Report of M. Off. of Local Gov. Board, 
1884, on " Chlorine and sulphurous acid on Swine fever virus ; and Crookshank's 
Bacteriology, 1887, p. 150. 

t Lehmann's Hygiene, tr, by Crookes, 1893. 

XMed. Chranide, Oct., 1890. § Patent No. 689, 1893. 


freeing it from dust, germs, &c., by blowing and washing, or sterilising 
with sulphurous acid, vapour of bisulphide of carbon, or other gas or 
vapour, by a tower arrangement down which the grain falls and is 
distributed and mixed in its course by baffling or deflecting pins. 
Thiosulphates (the " hyposulphites " of commerce) are antiseptic, but 
not strongly. 

Sulphuric Acid, H0SO4, stands next to hydrochloric as an antiseptic ; 
it is only partially a disinfectant. Koch first announced that the 
cholera bacillus was afiected by acids. Kitasato subsequently showed 
that this acid and hydrochloric destroyed cholera germs in a few hours. 

A. Stutzer* states that a solution of 0-05 per cent, of sulphuric acid 
is fatal to cholera bacilli in fifteen minutes (see Klein's remark, ante, 
p. 95). He tried 0-02 per cent., which took twenty-four hours; 0*03 per 
cent, even for five hours did not kill all. He also examined whether iron 
pipes could be disinfected by sulphuric acid without the metal being 
corroded, with the result that it cleaned out rust and sediment without 
sensibly attacking the metal. He estimates that 100 kilos, of 60° B. 
sulphuric acid (1 lb. of acid to 40 gallons of water) would disinfect 
40,000 litres of water at an expense for acid of about 0'9d. per 100 
gallons of water treated. Dr. Ivanoff t has also demonstrated that 
004 per cent, of this acid destroys cholera bacilli in Berlin sewage, 
and 0'08 per cent, in that from Potsdam. 

According to Miquel, 2 or 3 grammes of sulphuric acid produces an 
equal effect to 7 milligrammes of mercuric chloride. Endemann + 
found it very difficult to develop bacteria in fluids containing acid 
I)hosphates. Whitthread's patent, 1872, for precipitating sewage by 
acid phosphate of lime and then milk of lime, was tried at Luton in 
1874, and very favourably reported on by Corfield. He used a solution 
of 1 in 1000. The use of acid phosphates was proposed previously 
by David Forbes, and several patents claim them as disinfectants. § 
Endemann has also shown that many acids are powerfully disinfectant, 
destroying the life of bacteria completely, even if present in small 
quantities (but not of spores?). One part of hydrochloric acid in 64 
parts of Cohn's fluid well stocked with bacteria, destroyed these com- 

The toxine Caclaverine, C^Hj^No {Brieger), occurs in the products of 
cultivation of the cholera bacillus. Kobert |] says that it is less dan- 
gerous when converted into a neutral salt. To this he attributes 
partly the benefit derived in cholera from acid drinks (see p. 261, 

• Zeitsch. fur Hyg., 1893, p. 116. + Ihid., 1893, p. 80. 

X Chem. News, vol. xU., j). 152. 

§ Corfield and Parkes, on Treatment and Ut'diaation of Setcaije, 1887, p. 30G. 

II Pharm. Centralhalle, 1891, p. 162. 



Chap, xiii.), and from washing the intestines with acid liquids, of which 
weak sulphuric is the best, especially as it has been shown that the 
cholera bacillus itself is affected by traces of acid. 

Rohe* is of the opinion that whilst sulphuric acid, 1 in 800, is 
antiseptic in some cases, it cannot be depended on as a general 

The Sulphates are not perceptibly antiseptic. Miquel concludes 
that sodium and potassium sulphates, even dissolved to saturation in 
beef tea, are incapable of preventing the germination of bacteria. 
Sulphates of lime and magnesia actually encourage the growth of 
many organisms, being reduced to sulphides. Those of iron, mercury, 
and some other metals depend for their power on the base present, 
and not on the acid. 

Bisulphide of Carbon, CS,, is a colourless liquid, very volatile (boiling 
point 48° C), and exceedingly inflammable ; the vapour has caused 
dangerous explosions. It is heavier than water (sp. gr. 1*272), and 
insoluble in it. It has ordinarily a most offensive odour and is ex- 
tremely poisonous, its vapour forming in the blood methsemoglobin, 
with destruction of the corpuscles, f In Patent No. 3,208, 1878, M. 
Simon exposes meat to the vapour of this compound for preservation. 

Dujardin-Beaumitz used carbon bisulphide internally for typhus and 
diarrhoea, and found that " all offensive odours were removed from the 
breath and the stools were disinfected." J 

By burning it generates large quantities of sulphurous acid mixed 
with carbon dioxide. The yield cannot well be increased by dissolving 
sulphur in it, as the latter mostly remains unburnt in the dish. 

Messrs. Price & Co. have devised a lamp for burning this liquid, so 
as to generate these gases,§ but it must be used with caution on 
account of its volatility and inflammability. 

Carbon bisulphide is decidedly antiseptic, but its characteristics 
prevent its use. In combination with sulphides of alkalies it yields 
the sulphocarbonates, such as the potassium salt KgCSg, which crystal- 
lises in yellow needles, soluble in water and unstable. With an 
alcoholic solution of potash it forms an ethyl-sulphocarbonate or xan- 
thate, CS(OC2H5)SH. 

According to P. Zoller,|| small quantities of xanthates mixed with 
the soil prevent the formation of fungi. Zoller and Gretell recommend 
potassium xanthate as a remedy against Phylloxera. 

* Hygiene, 1890, p. 357. 

t See Westberg, Zeitsch. fur Anal. Chem., vol. xxxi. [4], p. 484. 

i Complea Rendus, vol. xcix., p. 509. § Parkes, Hygiene, p. 517. 

II DingLpol. J., vol. ccxxi., p. 191; vol. ccxxiL, p. 190. 

IF Ber., vol. viii., pp. 802, 955. 


Dr. Ross considers that the poisonous action of carbon bisulphide 
practically excludes it from use as a disinfectant. 

Aqueous solutions containing 1 or 2 grammes of carbon bisulphide 
per litre have also been found very satisfactory against Phylloxera. * 


Boric or Boracic Acid, H3BO3 (or HBOo . H^O) occurs in inodorous, 
pearly crystalline scales, sparingly soluble in water (about 4 per cent.), 
and more soluble in alcohol. The crude Tuscan volcanic borax has to 
be refined for preservative uses. It has been proposed, in an Italian 
patent, to import it in the native solution, but the cost of transport 
would thereby be increased. 

It is a weak acid, almost tasteless in dilute solution, and has no 
corrosive action either on tissues or metals ; this and its absence of 
odour, with a certain amount of preservative power, and little effect 
on animals, have led to a large number of patents for the use of boric 
acid and borates for preventing the putrefaction of animal and vege- 
table substances. It is in no sense a disinfectant, and its antiseptic 
powers are low, although for many years it has held a place as a 
preservative for meat and vegetables. The original discoverer, Gahn, 
sold in Europe two mixtures — (1) boric acid with 1 part alum, called 
"aseptine;" and (2) boric acid with 2 parts alum, called "double 
aseptine." It seems probable that he recognised in the alum a greater 
activity than in the boric acid. Provisions in part preserved by boric 
acid are generally within one or two months covered with a black 
crust, but the presence of alum prevents this action taking place. 
Lehmann found that fresh beef with 1 per cent, of boric acid and 
50 per cent, salt pickle kept for several months at 80 °F. Endemann 
proved f that boric acid acted as a preservative to fresh meat only, 
and that previously salted meat could not be preserved by it. 
Lehmann infers in these cases it is not the boric acid that acts as a 
preservative but the substances produced by it, i.e., the acid phos- 
phates (see under sulphuric acid, p. 97). He states that "other 
mineral acids give exactly the same results without boric, especially 
phosphoric and hydrochloric." % 

Miquel classes it as "moderately antiseptic." It required 7'5 
grammes to " neutralise " a litre of beef tea. 

According to Lazarus § milk can only be preserved by boric acid 
if the quantity added exceeds that which can be used without altering 

* Compt'es Rendus, 1S91, pp. 1113, 1283, and 1330. 
t Chem. News, April 2, 1880. 

X Lehmann, Practical Hygiene, 1893, vol. ii., p. 247. 
§ Zdt8, f. Hygiene, vol. viii. 


the taste. The microbicidal action of boric acid is very feeble. He 
is of the opinion that from 1 to 2 grammes i)er litre is without action 
(compare Miquel) ; yet Stokes * states that 1 in 1000, or roughly 
7 grains per pint, of boric acid will keep milk ''sweet" for forty 
hours. The difference is a question of time. 

Mattern finds 1 per 1000 retards the coagulation of milk from 
twenty-four to thirty-six hours. 

This acid has no action on vinous fermentation ; it retards the 
formation of acetic acid from alcohol by mycoderma aceti only when 
acetic acid is not already present.^ Lehmann sums up thus — "preser- 
vation by boric acid cannot be considered as involving a new 
principle ; it is merely a variation of, but by no means an improve- 
ment on, vinegar pickling. The insipidity prevents its easy detection, 
and brings customers to the belief that the meat is fresh. This 
peculiarity is the only one recommending the use of boric acid." 
Dr. C. T. Williams, of Brompton Hospital, proved that the acid 
excercised no destructive influence on the bacilli of phthisis. In 
fact they increased abundantly in boric solutions and develop spores. 
A warm saturated solution of boric acid was recommended by Pasteur 
as an antiseptic in cases of puerperal fever, but has been superseded 
"by mercuric chloride in the lying-in hospitals of Paris. The 
application of it to wounds and ulcers has decreased, J and in the 
French Army Medical Service four times as much sublimate wool 
is used as that impregnated with carbolic or boric acids. The latter 
wool contains from 14 to 36 per cent, of boric acid, which is in great 
jiart crystallised, and therefore irritating to the skin. This crystal- 
lisation may be prevented by keeping the wool moist by glycerine.§ 
There is no doubt that boric acid does preserve food when used in 
sufficient quantity. The earlier investigators employed such strengths 
iis 1 in 12 {Jalan de la Croix); ^ to 4 per cent. [Neumann); whilst 
Tallin, who used 2 to 4 per cent, of the acid, states that this strength 
kills germs when borax only stupefies them.|| 

Borates. — Those occurring naturally are Tincal or native Borax, 
Boracite or Magnesium borate, and Borocalcite or Calcium borate, and 
others of less importance. Those which are soluble are somewhat 
antiseptic ; they are decomposed by strong acids. The acid magnesium 
biborate is one of the most soluble, and may therefore be a useful salt 
for preservative purposes.H 

Borax, or Sodium diborate, Na^B^Oy, occurs in large transparent 
crystals, inodorous, having an alkaline taste and reaction, and soluble 

* Analyst, 1S91, p. 123. t Herzen, Biedermann's CentralblaU, 1S80, p. 487. 
X Lancet, vol. i, 1890, p. 1266. § Chemist and DruQgist, Feb. 18th, 1893. 

jl Vallin, p. 149. IT Brit. Med. Joum., 1888, p. 1184. 


in 12 parts of water. M. Dumas, in Aug., 1872, introduced boric 
acid and borax to the French Institute as preservatives for food. 
Borax may be used to neutralise the acid developed in milk by 
keeping. E. le Cyon * thinks that meat preserved by borax is not 
diminished in nourishment, and is more readily assimilated. Subse- 
quent investigators have, however, arrived at an opposite conclusion. 

Ammonium Borate is more soluble ; a strong solution has been 
injected into bodies for dissection. 

Among the numerous patents are — No. 2,375, 1877, Taylor, 
calcium borate; No. 3,001, 1880, Artimini, "boric tartrate" as an 
antiseptic; No. 4,910, ditto, ditto, boric acid and borax; No. 1,127, 
1882, J. Imray, preserving meat with boric and malic acids ; provi- 
sional i)rotection ; 1882, Haddan, borax, glucose, and boric acid 
evaporated till solid, for provisions; No. 5,153, 1882, Pielsticker, boric 
acid melted with sodium phosphate and formate, " very soluble and 
almost tasteless, for provisions ;" No. 6,134, 1882, J. Townsend, boric 
acid, «fcc. ; No. 274, 1883, Wilkins, ditto (these two are mainly 
mechanical); No. 1,429, 1883, Conron, boric acid, borax and potas- 
sium nitrate, "half a pint of concentrated solution to a barrel of 
3G gallons," for various infusions; No. 5,326, 1883, Lake, glycerine 
and boric acid (not heated, compare Barflf's patent). 

" Boroglyceride," No. 1,332, 1881, F. S. Barff, deserves further 
mention. " Heat glycerine to near its boiling point, and add 
boric acid as long as dissolved. Keep at 200° C. as long as water 
comes off. Animal or vegetable matter is preserved by immersion in 
a solution of the compound in water, alcohol, or other solvent." Boro- 
glyceride claims to be glyceryl triborate — 

C3H5(0H)3 + .3HB02 = C3H5(B02)3 + SHgO. 

How far, like other esters, dilution breaks it up again into glycerine 
and the acid, is not apparent. The solution has a different taste from 
the materials, but the general properties are intermediate in their 
character. It has hardly answered expectation. See under Glycerine 
(p. 226) for the therapeutic effect of that body. Calcium and sodium 
boro-glycerates, obtained by heating calcium borate or borax with 
glycerine till the whole forms an oily liquid which solidifies on cooling, 
are recoramendeil by Le Bon f for preserving food and for surgery. 

It will be noticed that most of the above devices are intended to 
increase the sparing solubility of boric acid. It is one of its charac- 
teristics that, though having so feeble an affinity for bases, it seems 
always ready to form more or less stable combinations with other acids 
and with neutral bodies. 
* Bied. Centr. Ayr. Chem., 1879, p. 869. + Comptea Rendtu, vol. xcv., p. 145. 


Potassic Borotartrate or "Soluble Tartar," K(B0)C4H^0g, obtained 
by heating together 1 part of boric acid, 2 of cream of tartar, 
KHC^H^O^, and 24 of water, evaporating to dryness, and treating 
■with alcohol to remove excess of acid, is a white non-crystalline 
powder, insoluble in alcohol but very soluble in water. It has been 
employed as a purgative, and also as an antiseptic, and is the " boric 
tartrate " of Artimini's patent mentioned above. 

Benzoboracic acid, with oils of thyme, Eucalyptus, Baptisia, Gaul- 
theria, and Mentlm arvensis, containing 1 part of the acid in 30 of the 
oils, is called " Listerine," and is used in surgery. There is also a 
benzo-boric mouth-wash. Salicylic acid is soluble in less than GOO 
parts of water ; stronger solutions may be made by using boric acid 
in the proportion of 12 parts boric acid to 1,000 of water, when a 
0*2 per cent, solution of salicylic acid can be obtained.* Strock's 
" Antiseptic paper " is made with two solutions — A, alcohol 500, 
boric acid 5, salicylic 7 ; B, water 1,588, sodium tliiosulphate 60.f 
E-adlauer's " Antisepsin " is a mixture of zinc sulphate 85, zinc 
iodide 25, thymol 2*5, with 10 parts of boric acid. 

L. Hausler I has recently made boroglyceride into a jelly by dissol- 
ving it in hot water with half or an equal weight of gelatine ; he dips 
the provisions while the jelly is still liquid, and so gives them a pro- 
tective coating. Before use the articles are washed in luke-warm 

Boric acid is also used for preserving butter and cream, for curing 
hams, sprinkling over fish, &c. "Sodium chloro-borosum " is borax 
and common salt. " Barmenite," according to C. Schwartz, contains 
80 per cent, borax, 15 boric acid, 3 salt, and 2 sodium chlorate, with 
traces of alumina. " Glacialin " is a fused mixture of borax and boric 
acid.§ These preparations are extensively used on the Continent for 
preserving meat, and the latter in this country for milk. How much 
boric acid enters into meat which is sprinkled with or soaked in it is 
not accurately known, but according to Roosen, who has patented the 
use of boric solution under pressure, 500 grammes of meat take up 
only ^ gramme of the acid. Covering meat with 1 per cent, boric 
solution keeps it from putrefaction from four to seven days. 

Hehner states,|| on the authority of Polenski, that in Germany boric 
acid preservatives have been advertised under the following names : — 
Berlinite, Chinese preservative powder, Brockman's salt, Australian 
salt, Magdeburg preservative salt, and Heydrich's salt. 

The physiological effects of borates in food seem to be more pro- 

• Bevue de Chimie Industrielle, April 15, 1893. t JbicL, Feb. 15, 1893. 

t Patent No. 9,145, 1893. § Journ. Soc. Chem. Ind., 1890, p. 993. 

II Andlyat, 1890, p. 295. 


nounced than was formerly supposed. Artimini and Polli asserted 
that doses of 3 or 4 grammes continued for months were well 
tolerated by men.* Large doses produce vomiting and diarrhoea, 
«fec.,t but dilute solutions seem to have no visible effect. Forster 
and Schlenker have shown, in very careful and repeated experi- 
ments, that daily doses of i to 3 grammes of boric acid added to 
human diet affect the absorption of nutritious substances ingested, 
irritate the intestines and cause them to cast more mucus and epi- 
thelium. Borax probably acts like boric acid. J Forster concludes 
that the use of boric acid in preserved food is of questionable value, 
as it increases the secretion of bile and the excretion of albuminous 
matters. Gruber likewise states that the decomposition of albumen 
in animals is increased by borax. The use is said to be greatly ex- 
tending, but preparations of borax for preserving meat are forbidden 
in the German navy. 

A French commission appointed to investigate the influence of boric 
acid on the human system reported that it could be taken for a con- 
siderable time without injurious effect. "Yet it is certainly neither a 
regular constituent of the body nor naturally contained in food (beyond 
exceedingly minute traces), and it is therefore probable that in time 
constitutional difficulties would supervene."§ Leffinan and Beam|| 
and H. A. "Weber H have shown that food preservatives interfere with 
pancreatic and salivary digestion, borax even keeping its retarding 
effect up to a dilution of 1 in 2,000. Both boric acid and borax delay, 
or even prevent, germination of seeds.** 

If, as stated by Stokes, it requires 1 in 1,000 of boric acid to keep 
milk. sweet for forty hours, 2 grains per diem are consumed per adult, 
and 15 to 30 grains daily by a bottle-fed baby. This amount may 
fairly be regarded as a medicinal quantity, and it is to be hoped that 
legislation will prevent its use in the future. 

Tests for Borates. — To a large quantity of the milk, or of the aqueous 
extract of the food, add milk of lime in excess. Evaporate to dryness, 
burn to ash, and dissolve in a little strong hydrochloric acid. Filter, 
nearly neutralise the acid with lime, dip into it a piece of freshly 
made turmeric paper. Dry this on a water bath; if boric acid be 
present, the portion which has been dipped will show a rose colour, 
turned dull blue by dilute soda. If there be much boric acid, the 

* Annali di Chem. Med., 1877. 
+ Neumann, Archiv.f. exp. Physiol., 1881, p. 148. 
X Ber. deutsch. Chem. Ges., voL xvi., p. 1754. 

§ Acad, des Sciences, Jan. 6, 1879. I| Joum. Soc. Chem. Itid., 1888, p. 582. 

■H Joum. Amer. Chem. Soc, 1892, p. 4. 
♦* Comple* liendus, 1892, voL «civ., p. 131. 


remainder of the ash solution, if moistened with spirit, ignited, and 
stirred, will show a green mantle to the flame against the red of the 
calcium chloride and yellow of the soda. The green lines of boric acid 
should be looked for in the spectroscope.* The quantity may be 
determined by repeated distillation with methyl alcohol into a crucible 
containing a known weight of ignited lime, t 

Kayser J says that traces of boric acid are very widely distributed 
in nature. Carrots, beet sugar, Californian wines, &c., contain it, and 
it is often introduced into the glaze of enamelled vessels. But these 
would only be minute traces, whereas as a preservative it would be 
present in comparatively large quantities. 


Bacteria have been divided into two classes — I., the aerobic, which 
live and work in presence of oxygen, and die when it is exhausted ; 
their gaseous products are chiefly carbonic acid and ammonia : their 
type is Bacterium termo, the principal agent of putrefaction ; they 
can be dealt with by exclusion of air, as in preserving in tins, especially 
if sterilised first, or by reducing agents such as sulphites ; — II. the 
anaerobic, which exist in absence of oxygen, and are killed hy its 
presence. Many of the pathogenic organisms belong to this latter 
class. Among the products are marsh gas, sulphuretted hydrogen, 
phosphoretted hydrogen, carbon monoxide, nitrogen and ptomaines. 
Oxidising agents like chlorine, hydrogen peroxide, and permanganate, 
are their most effective destroyers. These bacteria take up the pro- 
cess where the aerobic have ceased, hence the necessity of sterilising 
before excluding the air. 

On the principle that all living beings are first restrained, and 
finally killed by their own excreta, any of the above gases should be 
to a certain extent poisonous to the micro-organisms which produce 
them. But they will be far more fatal to higher animals, the effects 
being not only on the blood and the lungs, but also on the central 
nervous system ; the more highly developed the organism, the greater 
is the sensibility . § 

Carbon dioxide, or "carbonic acid" COg, seems to have a special 
antiseptic and even disinfectant action, inasmuch as aerated waters 
and beverages have been found to be in many cases sterilised. 
Slater il has found that this gas in mineral waters has a remarkable 
effect in killing pathogenic bacteria (typhoid, cholera. Staphylococcus 

* Kretzchmar, Chem. Zeit., vol. xi., p. 476. 

t Cassal, Analyst, 1890, p. 230. t Chem. Zeitung, 1890. 

§ Pettenkofer and Lehmann, MiincJien Acad. d. Wlasensch., 1887, p. 179. 
II Journ. of Pathol, and Bacteriology, 1893, vol. 1., p. 468. 


j)yogenes aureus, Finkler-Prior bacillus). Ilochstetter * found the 
same in the case of typhoid, cholera, rabbit septicaemia. Micrococcus 
tetragemis, Finkler-Prior bacillus, Aspergillus Jlavescens, and anthrax 
bacilli but not anthrax spores. 

It is well known that fermented liquors preserved in bottles remain 
stable for long periods, and this stability seems difficult to explain 
by the self-exhaustion or deposition of any bacteria present. Bethell 
in 1848 patented a process for preserving milk, which consisted ini 
first boiling the milk to expel all the air contained in it, and then 
saturating the liquid with carbon dioxide. The milk when so treated 
remains fresh for a long time after being opened. Liquefied carbonic 
acid has also been used for preserving food. Thus, butter when 
placed in an iron vessel provided with a tap, and subjected to carbonic 
acid under a pressure of 6 atmospheres until all the air has been 
driven out, remains fresh for four or five weeks, and is not spoiled 
in flavour or consistency. Carbonic acid may also be injected into 
whey, giving " a refreshing drink like champagne. The carbonated 
whey can be enclosed in syphons and will keep for 6 weeks."! This 
method is quite innocuous, and should be substituted for the use of 
salicylic or boric acid or glycerine. 

Cyanogen and hydrocyanic acid vapour do not seem to be so poison- 
ous to lower organisms as they are to the higher animals. 

Miquel gives 0-4 of hydrocyanic acid per 1000 as sterilising beef-tea. 

Ammonia, sulphuretted hydrogen, sulphurous acid, chlorine, oxygen^ 
ozone, and oxides of nitrogen are described under their respective 

* Arbeilen a. d. kais. Gesundheitsamte, 1887, vol. ii, p. 1. 
t C/iem. Traile Journ., July 15, 1893. 



Salts of the alkalies and alkaline earths : Caustic alkalies — Quicklime — 
Sulphate of lime (Gypsum) — Slaked lime ; its use as a precipitant — Sodium 
carbonate — Acid salts — Ammonia and ammonium carbonate. Zinc : Oxide 
— Chloride of Zinc— Burnett's fluid — Zinc sulphate, sulphite, and other salts 
— ^Various patents. Copper : Poisonous action — Cuprous chloride — Cupric 
chloride, nitrate, sulphate, and acetate. Iron : The use of metallic iron for 
purifying waters — Ferrous sulphate of copperas ; the objections to it — Patents 
and processes — Ferric sulphate and its applications — Ferric chloride — The 
value of iron salts as disinfectants. Manganese : The metal — Manganese 
peroxide — Manganous salts — Manganates— Condy's fluids — Potassium per- 
manganate — Other permanganates — Mechanical devices — Cost. 


The hydroxides of potassium and sodium exercise an inhibitory 
influence on bacterial growth if they are present in quantities of not 
less than 2 to 5 per cent. ; so do the carbonates in the proportion of 
5 to 10 per cent. ; the bicarbonates have hardly any action. Miquel 
classes caustic soda as "moderately antiseptic," stating that it 
requires 18 grammes per litre to preserve beef tea. He asserts, 
also, that many other potassium and sodium salts, and especially the 
sulphates and nitrates when dissolved to saturation in beef tea, are 
incapable, even in the proportion of 500 per mille, of preventing the 
germination of bacteria. 

In laboratories it is noticed that the development of green Proto- 
coccus occurs most rapidly in solutions of potassium, calcium, and 
magnesium sulphates, and sodium phosphate. Calcium chloride solu- 
tions also rapidly show growths if exposed to air. Strontium salts 
do not seem to display any difference. The alkaline acetates, and 
tartrates quickly become mouldy, even in very strong solutions. It 
will be remembered that all varieties of protoplasm contain salts of the 
Alkalies and alkaline earths ; these, therefore, are actually favourable 
to the life of organisms, and thus are always added to Pasteur's and 
other artificial culture solutions. 

Sodium chloride and the alkaline sulphates have already been 
discussed (pp. 70, 98). Forster * states that salt (NaCl) destroys the 
cholera bacillus, but not others. In curing hams the saltpetre is 
* R. Acad, of Science, Amsterdam, April, 18S0. 


added to affect the colour and taste; it has no proved antiseptic 
action. Since nitrates are produced by the nitrifying organisms by a 
process of oxidation, and reduced to ammonia by the growth of other 
bacteria, and as these latter are very numerous the nitrates may 
properly be regarded as salts favourable to the development of many 

The weak antiseptic action of potash and soda may account for 
the similar slight activity of soap, as the fatty acids do not seem to 
have any very pronounced antiseptic action. 

Sulphate of Lime, on account of its power of absorbing ammonia, is 
a deodorant, but cannot be regarded as an antiseptic. When used in 
agriculture it prevents the ammonia from escaping, but does not hinder 
the decay. It has been a frequent ingredient in mixtures for pre- 
cipitating sewage ; it only acts mechanically, and has the great dis- 
advantage that it adds to the permanent hardness of the effluent water 
(Corjield and Parkes). 

Carbonate of Lime, and in fact all other insoluble metallic salts, are 

Quicklime, CaO, acts only as an absorbent; it destroys organic 
matter by its dehydrating action, and to this cause may be attributed 
its use for accelerating the decomposition of corpses dead of infectious 
diseases. There are very few microbes that can remain active auy 
length of time in a dry state, but the bacilli of tubercle have been 
known to exist in dry dust for more than a year.* The spores of all 
known species resist drying for indefinite periods.! It is not safe, 
therefore, to trust entirely to the old method of burying in lime, as, 
on disinterring, the live spores may again be diffused, unless a very 
long period has elapsed. 

Slaked Lime or calcium hydrate, Ca(0H)2, absorbs acid vapours 
and sulphuretted hydrogen, and therefore acts to a certain extent 
as a deodorant. Vallin says J that limewash applied to walls is 
in a certain degree antiseptic, as it forms insoluble compounds with 
the organic matter present in condensed pulmonary exhalations. 
For instance, it coagulates albumen and casein. This would deprive 
bacteria of food, as shown by the experiments of Pettenkofer, 
made for the German Cholera Commission of 1879. He concludes 
that ''slaked lime destroys rapidly and completely the organisms 
of putrefaction ; the proportion of | per cent, is sufficient for slightly 
altered bilge-water, but when the putrefaction is strong, 1 per 
cent, is required. The action on wood and metal is very slight, 

* See on the "Vitality of Bacilli : Dr. Buchner, Ohio Sanitary Record, April, 1894. 
+ Klein, in Stevenson's Hygiene, 1893, p. 61. 
J Traite des Disinfectants, 1S82, p. 70. 


but the lirae removes the odour of the fatty acids of putrefaction, which 
is often more offensive than that of suli)hinetted hydrogen." He 
mentions as a difficulty the blocking up of pipes and pumps when it is 
used. The precipitation of sewage by milk of lime was the tirst 
process tried by the Rivers Pollution Commission of 18G8, and was 
pronounced to be a failure.* In the act of settling, the suspended 
lirae carries down the greater portion of the organisms with other 
impurities, and renders the water clear. It has been stated also that 
the lime coats the bacteria and their spores with an insoluble envelope 
of carbonate of lime. This is the fundamental idea of the use, general 
in Leipzic, of the "Suvern mixture" for sewage (see chapter on 
"Regulations," p. 292). This theory does not seem to have been 
verified by microscopic examination. But many investigators have 
proved that, although the changes are much delayed, the water is not 
sterilised. The liquid is rendered alkaline, ammonia is developed, 
and, in the case of sewiige, the effluent soon again becomes foul. 

The State Board of Health of Massachusetts! found that it required 
about 2,000 lbs. of lime to 1,000,000 gallons of sewage to reduce the 
bacteria to an average of ^^^j of what they were before. In the same 
experiments it was found necessary to add alum or aluminium sulphate 
in addition, to prevent the subsequent distribution of the precipitated 
microbes in the upper layers. 

Numberless experiments on sewage have proved that, although a 
partial deodorant and a claritier, lime alone is not an antiseptic, and 
still less a disinfectant. 

The use of lime water for preserving eggs depends on the deposition 
of carbonate of lime in the pores of the shell, rendering it impervious, 
and also to the lirae coagulating tlie albuminous envelope of the egg. 

Sodium Carbonate, "Washing soda." — A strong solution is antag- 
onistic to bacteria, but, as used for clothes, &.C., is not effectual without 
boiling. Reinsch I says that 0*1 percent, of sodium carbonate (Na.,C03) 
caused the multiplication of bacteria, whereas 1 per cent, diminished 
the number, and 3 per cent, killed them in a sample of the Elbe water 
from between Hamburg and Altona. 

Surgical instruments, after being well washed with soap and water, 
are frequently sterilised by boiling in a solution of bicarbonate of soda, 
^ oz. to the pint. 

The acid salts of alkalies act by virtue of their acidity, as men- 
tioned under Sulphuric Acid (p. 97). Acid phosphates probably 
have the most power in this way, but none of them have much 

* First Report R. P. Comm., p. 52. -[Reports, 1888-90, vol. xi., p. 737. 

t CerUr. /. Bakt., 189), vol. x., p. 415. 


Kingzett lias made some experiments on the effects of chlorides, 
nitrates, and sulphates on the growth of mould on flour-paste, and on 
the putrefaction of extract of beef. His results generally corroborate 
the statements made above.* 

Ammonia is a product of the growth of many bacteria, and can there- 
foie only be a restraint on them when it is present in sufficient quan- 
tity to kill them by re- imbibition. Miquel classes it as " strongly 
antiseptic," saying that it requires 1 "4 grammes per litre to preserve 
beef tea. 

Ammonium Carbonate, or smelling salts, has a similar action. The 
same authority mentions ammonium chloride and sulphate as " very 
feebly antiseptic," the former requiring 115 grammes per litre, and the 
latter 250 grammes (or a quarter of the weight) to keep beef tea from 


Oxide of Zinc, ZnO, is a white basic powder, and, "being slightly anti- 
septic and emollient, has found favour in ointments. 

Chloride of Zinc, ZnCl.,, is an exceedingly deliquescent and caustic 
salt ; 10 parts dissolve in 4 of water, 1 in 1 of rectified spirit, 1 in 
4 (nearly) of glycerine. Its solution is acid, tastes strongly metallic 
and astringent, and is very poisonous. Miquel placed it in his class 3 
as "strongly disinfectant," stating that 1"9 parts in 1,000, sterilised 
beef tea. It is one of the most powerful of antiseptics, ranking next 
to copper sulphate and mercuric chloride. Grace Calvert found that 
a solution of albumen, to which 1 per mille of zinc chloride was added, 
required over forty days before germs developed. Koch says + that 
zinc chloride does not act as a germicide, and that even a 5 per cent, 
solution was utterly useless. This was based on anthrax spores, which 
are apparently the most difficult of all to kill. Dr. Hamilton believes 
that although it may not kill the germs it may make the surface a 
barren spot as far as germs are concerned — i.e., act as an antiseptic. 
Dr. Richardson made experiments with regard to this salt, confirming, 
on the whole, the views of Dr. Hamilton. In 1875 and 1S76 Petten- 
kofer and Mehlhausen directed a number of trials in the German 
Fleet on the disinfectant value of zinc chloride. Bilge-water of a 
specific gravity of 1017 to 1035, with a slightly alkaline reaction, at a 
temperature of 20° to 30° C, was treated with a solution of 50 to 
60 per cent, strength in the proportion of 1 part to 100 of bilge. 
A greyish flocculent precipitate rapidly settled, leaving a nearly clear 

• Brit. Med. Joum., vol. i., 1888, p. 150. 

t Miquel, Les Org. de I'Atmosphire, 1883, p. 289. 

tMUtheil. a. d. k. Gesund., 1881, p. 234. 


yellowish liquid. All odour ceased, the organisms seemed to be killed, 
and the reaction became remarkably acid. At the end of four 
weeks the mixture showed no signs of change. One part of the solu- 
tion to 1,000 of bilge caused a decrease of the odour; 2 in 1,000 com- 
pletely removed sulphuretted hydrogen, much reduced the rancid 
smell, and preserved the liquid for fourteen days. 

A 5 per cent, solution was found to possess no corrosive action on 
iron, brass, wood, or caoutchouc. It neither bleaches nor rots ordinary 
fabrics, but causes a reddening and slight smarting sensation on the 
skin. The deposit does not clog the pipes or valves of the pumps as 
that formed when lime is used. The German Cholera Commission of 
1879 prescribed zinc chloride for the disinfection of bilge-water. 

In surgery an 8 per cent, solution of zinc chloride has been employed 
by Sir J. Lister for antiseptic dressings. A solution of 1 to 5 per cent- 
is sufficiently strong for most purposes.* 

Sternberg f finds that a 2^ per cent, solution destroys bacteria, but 
a 1 per cent, solution does not prevent inoculation being followed by 
death. F. Boillat J points out that although a 5 per cent, solution 
does not kill the spores of splenic fever, it is nevertheless a good anti- 
septic. He has also shown that it and zinc sulphate both combine 
with albumen to form albuminates, and that, provided sufficient of the 
salt be added to unite with the whole of the albumen, no growth can 
take place. In Koch's experiments he believes that the quantity of 
zinc salt added only precipitated part of the albumen, leaving therefore 
sufficient pabulum for the spores on the threads to develop. 

Under the name of £ur7iett's Disinfecting Fluid this salt has had an 
extensive use in this country. This fluid is made by allowing the 
solid salt to deliquesce to a syrup, then adding water, if necessary, till 
the strength is 46 to 50 per cent, of zinc chloride. 

Parkes § strongly recommends it for excreta, especially for military 
use. The French Pharmacopoeia prescribes a solution of 1 in 6 with 
1 per cent, of hydrochloric acid to dissolve the basic chloride which, if 
present, would render the solution not only turbid but somewhat 

Burnett's fluid and the Dublin Pharmacopoeia solution have a 
specific gravity of 2*00, but commercially, as being formed by mere 
deliquescence, are of varying strength, generally about 82 per cent. 
The " Liquor Zinc Chloride" has a specific gravity of 1'46 (1*53, Squire's- 
Companion, 1890), contains 25 per cent, of zinc, or about 52 jier cent. 
of the chloride. De Ohaumont found in a sample of Burnett's fliiid 

*Vallin, Disinfectants, p. 128. 

iBvil N. Board of Health, U.S.A., 1881, vol. iii., p. 21. 

XJoum.f. praktisch Chem., vol. xxv., p. 300. % Hygiene, 1878, p. 400. 


69 per cent. Woodman and Tidy * give 47 to 53 per cent, as the 
strength. This variability is a great fault of the solution ; it would 
be better to state the percentage of zinc, as in the British Pharma- 
copceia (25 per cent. Zn). Burnett's original formula is unknown 
(de Chaumont). 

The medicinal preparations are : — Lotion, 1 grain of the liquor in 
1 oz. of water, or about 1 in 1,000 of zinc chloride (London Ophthal- 
mic Hospital) ; jmste, liq. zinc chlor. and flour, equal parts ; glycerine, 
enough to make a thick paste ; an excellent antiseptic for wounds 
(London Hospital) ; opium is often added. Compound powder, zinc 
oxide mixed with an equal weight of zinc chloride keeps the latter 
dry enough to blow into cavities. Points or darts of zinc chloride 
fused in moulds and kept in glass tubes have been used in the treat- 
ment of anthrax.t Compound ditto, equal weights of the oxide and 
chloride mixed with 2 parts of flour and water to make a stiff paste, 
are milder and less irritating. 

The official strength for rooms is 1 of the fluid to 100 of water 
(about 1 of zinc chloride in 200) ; for sewers and closets half this 
strength may be used.| For excreta a 10 per cent, solution should 
be stirred in, using 1 part to about 9 of the excreta, making about 
1 per cent, of zinc chloride present. 

" Eau de Saint-Luc," which is much sold in France, is a con- 
centrated impure solution of chloride and sulphate of zinc, with 
occasionally some acetic acid. Specific gravity, 1-613; strength, 77 
per cent, of zinc chloride. It must not be used without dilution. § 

Prof. Lamelongue || injects small quantities of zinc chloride in tuber- 
culosis to promote induration of the tissue, so as to " encapsule " the 

Dr. Vidal, as an injection for fetid discharges, employed a solution 
containing 15 grammes zinc chloride, 1 gramme boric acid, ammonia 
to just neutralise, and 1 litre of water. H 

Daudenant patented a process for sewage,* * using lime, then salts of 
aluminium and zinc chloride. 

This salt is also used for injecting corpses, using 8 litres of a solution 
of 40° Baurae. 

Zinc Nitrate, Zn(N'03)o, as a caustic eats deeper with less pain. 
As a disinfectant it is inferior to the chloride, and more expensive. 

Zinc Sulphate, ZnSO^, 7H2O, occurs in transparent crystals, of acid 
reaction and styptic taste ; it is emetic and less antiseptic than the 


* Forensic Medicine. i B. M. J., 1887, vol. ii. p. 644. 

::: B. Med. B. of Heallh. § Vallin, p. 126. 

II Lancef, July 11, 1891. IT /6id., p. 346. 

• • Patent No. 4203, 1886. 


Calvert states that 1 in 200 will keep beef juice for 30 day.s "free 
from animalcules and fungi." Recent investigations by Koch, Klein, 
and others prove that it is of no value as a germicide. Still it has 
been a favourite substance to mix with sulphates of copper and mer- 
cury, probably from an idea of cheapness, although it is likely that it 
may add to their action. Patent No. 19,766, 1881, treats sewage with 
zinc sulphate. 

Bierbach states that an article sold as "urinal cakes" consisted of 
a mixture of the sulphates of zinc, copper, iron, and soda, also some 
alum with resin, the salts probably being fused with the resin so as to 
make them dissolve more slowly. Holmes and Em mens* propose to 
utilise the spent liquor of batteries, containing zinc sulphate and 
sulphuric acid, as a disinfectant. 

An acid solution of sulphate of zinc coloured with indigo has recently 
been used in Paris by M. Meillere for deodorising typhoid stools in 
the sick room. 

The disinfectant employed on the Pennsylvania Railway consists of 
a solution of the chlorides of zinc, mercury, and coi)per, with a little 
turpentine to act as a tell-tale. W. T. Sedgwick has tested this mix- 
ture upon various typical bacteria, and concludes that its efficiency is 
due to the mercuric chloride. f 

"Tuson's Disinfectant" is sulphite of lime with sulphates of alum- 
inium and zinc. Every pound of this mixture is said to give off 
7 gallons of sulphurous acid gas.} In his patent R. V. Tuson 
saturates a solution of zinc chloride (3 lbs. to the gallon) with sul- 
phurous acid gas. Mercuric chloride may also be added. § 

"Radlauer's Antisepsin " contains 85 parts of zinc sulphate, 25 of zinc 
iodide (a good but caustic antiseptic), 2*5 of thymol, and 10 of boric 
acid. It is said to be very successful for wounds and ulcers. 

" Eau Larnaudes" is composed of ordinai-y water containing 23 per 
■cent, zinc sulphate and 20 per cent, copper sulphate.|| 

Raymond of Paris has patented " an improved antiseptic, disinfect- 
ing, and deodorising fluid " of the following complicated composition: — 
Parts by weight : water, 1000 ; zinc sulphate, 300-500 (i.e., a saturated 
solution) ; zinc acetate, 10-3 ; sodium hyposulphite, 30-5 ; aluminium 
sulphate, 30-45; boric acid, 4-7; mercuric iodide, 0*10 to 0*25 (only 
when required very powerful).^! The hyposulphite would be decom- 
posed by the acid, and in its turn would precipitate the mercury as 

♦ Patent No. 4,061, 1883. t Tech. Quart., 1893-6, vol. ii., p. 43. 

X Lancet, 1891, vol. ii., p. 19. § Patent No. 12,222, 1887. 

II Notice 8ur le nettoiement de la voie publique, Ville de Paris, 1876. 
1 Patent No. 11,275, 1892. 


Zinc Acetate is used as an antiseptic in ophthalmia and gonorrhoea. 

Zinc Sulphite is insoluble. Tichborne and Henston* make an anti- 
septic gauze by boiling the latter with zinc sulphate, then dipping in 
hot sodium sulphite solution, and washing. Zinc sulphite, ZnSOg, is 
precipitated in the tissue. 

Acid Sulphite of Zinc is a soluble salt, and its use as an antiseptic 
has been patented by Boake and Roberts, t 

Zinc Sulphocarbolate is strongly antiseptic, has no odour, and docs 
not cause irritation. To spray the throat in diphtheria, kc, 5 grammes 
pejr ounce is used ; for the eyes, 4 grammes per ounce ; and for injec- 
tions, 60 grammes to the pint. These strengths seem very insufficient, 
but perhaps there is some danger of poisoning. 

Rotterine X contains 45 grains each of zinc chloride and sulphocarbo- 
late, 27 of boric acid, 2^ of sodium chloride, 6 of salicylic acid, and 
1 grain each of citric acid and thymol, all dissolved in a pint of water. 
It is said to be more effective than 1 per mille of mercuric chloride. 

Zinc Salicylate is antiseptic and sparingly soluble. Bovet § proposes 
to antisepticise all houses in the course of building, by incorporating 
5 per cent, of zinc salicylate in the plastei-, soaking the woodwork with 
4 per cent., and the papers and hangings with 1 per cent. He says 
that the additional expense does not amount to more than 2 per cent, 
of the total cost of construction. 

All soluble zinc salts absorb ammonia and sulphuretted hydrogen. 


The soluble salts of copper have a distinctly poisonous action on 
bacteria. They coagulate albumen, and combine with most of the 
organic acids present, to form non-putrescible salts. They absorb sul- 
phuretted hydrogen, ammonia, and compound ammonias, and therefore 
combine with "ptomaines." In fact, copper salts rank next to 
mercury in power as antiseptics. They are used (Kyan's method) for 
injecting timber to kill the spores of the fungi (mainly Merutiua 
lachrymans) causing dry rot. It is difficult by law to keep them out 
of pickles and preserved vegetables, as they improve the colour and 
add to the keeping qualities. In several cases of prosecution under 
the Food and Drugs Act, for copper in food, it has been adduced by 
authorities that a small quantity of copper is not injurious.]! Copper 
salts are not volatile, their action is, therefore, strictly local. As anti- 
septics they give way to zinc salts, since any surface washed with 

* Patent No. 11,985, 1890. + Patent No. 8,509, 1886. 

t Dr. Kotter, Chtm. and Drug., 1889, p. 35. 
§ Bull. Soc. Ind. MtUhouse, 1890, p. 546. 
Jl Soc. Chem. Ind., 1895, pp. 539 and 705. 



copper salts (or mercury) is blackened by sulphuretted hydrogen, 
whereas zinc sulphide is white. Nevertheless, M. Bureg recom- 
mended that curtains, clothing, wood, <kc., should be impregnated 
with copper salts. 

Cuprous Chloride, OugClg, is white, almost insoluble in water, bufc 
somewliat soluble in dilute hydrochloric acid. On exposure to air it 
becomes oxidised to cupric chloride, and therefore acts as a reducing 

Kroncke * points out that for sewage treatment, compounds having 
a great affinity for sulphur should yield the best results. He has 
experimented with cuprous chloride as being a salt which fulfils this 
condition. It is readily prepared, very easily removed from solutions, 
and becomes much less poisonous when oxidised. It has the further 
advantage of not being acted on by carbonate of lime. (2) The follow- 
ing method was found suitable for the purification of water : — Cuprous 
chloride amounting to o-xj^^j^y of the water to be treated, and ferrous 
sulphate (as far as possible free from ferric), to the extent of -g-^^Q^, 
are added to the water. After six hours, 177^7^577 P^''^ ^^ ^^^® ^^ 
added, and agitated for one hour. After settling for one and a-half 
hours, the water is filtered through sand. The water, which originally 
contained 40,000 to 50,000 germs per cubic centimetre, was then 
found to be completely sterilised, clear, almost colourless, and free 
from iron and copper. The sand filter can be used a long time 
without cleansing. The cost of purifying is estimated at Is. per 
1,000 cubic metres. The sediment may be burnt and the copper 

Cupric Chloride, CuClg, occurs as green very soluble crystals. 
Dr. Green f has examined various copper salts as to their relative 
value as disinfectants. He tried 1, 2i, o, and 10 per cent, solutions. 
The test objects were — twenty-four hour old bouillon cultures of 
cholera, enteric fever, Staphylococcus pyogenes aureus, anthrax free from 
spores, and spores of same dried on silk threads, besides several mix- 
tures of excreta and urine infected with cholera, &c. The 5 per cent, 
solutions were in most cases fatal after two hours, but with anthrax 
only the specimens on the threads were killed, and then only when in 
contact with a 5 per cent, solution of copper chloride for twenty-seven 
days, and with the 10 per cent, solution for eighteen days. The other 
solutions only retarded the growth. The general result is that cupric 
chloride is the most active, and that their relative activity is in accord- 
ance with the proportion of copper in the compounds — viz., chloride 
1 in 2*7, acetate 1 in 3-1, nitrate 1 in 3*8, sulphate 1 in 3*9. He 

* Joum. fur Gasbeleucht, vol. xxxvi., p. 513. 

f Proc. Ins(. Civil Eng., vol. cxiii., p. 42. Zeif, fiir Hyg., 1893, p. 495. 


states that 5 per cent, solutions of copper salts cost approximately the 
same as 5 per cent, carbolic acid. It is also pointed out that although 
cupric sulphate is somewhat extensively used as a disinfectant, the 
chloride should take its place as being the better salt to use. 

If the above results with anthrax be confirmed, there seems to be 
considerable risk attending the use of copper salts altogether, as it is 
impossible to be certain that anthrax or other spores are absent in 
general disinfection. 

Leveson and Slater* proposed for purifying sewage the addition of 
crude aluminium chloride (made by treating shale with hydrochloric 
acid), then chloride of copper, carbon, clay, and, finally, lime to 
neutralise the acid and precipitate the metals. This patent is typical 
of a large number of complicated processes that have been introduced 
for the utilisation of this salt for sewage treatment. 

Cupric Sulphate, CuSO^, SHgO, the cheapest copper salt, is sol- 
uble in 4 parts of water. To kill bacteria of putrefaction, according 
to Miquel,t a solution of 1 in 111 is required ; according to Bucholtz| 
1 in 133. Calvert and M'Dougall found that a strength of 1 in 900 
prevented the growth of organisms iu beef tea for eighty-six days. It 
may be taken, then, that 1 per cent, is disinfectant, while 1 in 1,000 
is antiseptic for most bacteria. Kingzett also noticed that a solution, 
of 0'25 per cent, of cupric or mercuric sulphate prevented putrefaction 
in bi-oth for sixteen days ; the observation did not last longer. § 

The French authorities (1892) decided to adopt as their official 
disinfectant, in combating the cholera, sulphate of copper in a 5 per 
cent, solution, and, specially for the disinfection of rooms, a solution 
of corrosive sublimate and tartaric acid in the proportion of 1 of the 
former to 3 of the latter. 

EaiL Desinfectante Larnaudes, sold in France, is a mixture of the 
sulphates of copper and zinc. Vallin states || that this solution usually 
contains only a little copper, and that when used as spray on walls, 
and floors persons entering the room just after the operation notice 
a marked cupreous taste and the styptic flavour of the zinc salt. 
Vincent disinfects faeces and the contents of cesspools with acid copper 
sulphate, using 6 kilos, per cubic metre per twenty-four hours.H 

Cohn, in experiments on chicken cholera, considered sulphate of 
copper and chloride of zinc superior to borax and chloride of lime. 
But the German government have adopted neither of the former. 

Verdigris (cupric acetate) is used as a wash for destroying the 
parasites of plants, especially Feronospora in/esfans, the potato blight. 

* Patent No. 11,641, 18S4. t Les Organismes, p. 289. 

:J: Arch. exp. Pathol., voL iv., p. 1. § Lancet, 1889, vol. i., p. 144. 

II Disinfectants, p. .62. IT Compt. Bend., vol. cxix., p. 965. 


Still better is the copper-lime-sugai* wash of Michel Perrei.* These 
and the sulphate are also used for soaking seed, corn, &c. 

Fumigation with copper salts does not seem possible, but Clemens f 
proposed a lamp filled with a solution of cupric chloride in alcohol 
and chloroform, which when lighted is meant to give off vapours of 
copper chloride. Reichardt f pronounced its use to be offensive, 
poisonous, and variable. Clemens also sprinkled the straw, &c., in 
stables infected with rinderpest with the same solution. For this it 
would doubtless be efficient, but the expense would be very great, and 
the animals must be removed. 

Bona§ proposed a mixture of cupric sulphate and alum under the 
name of " Cupralum." 


Metallic Iron has long been used as a purifying agent for waters 
exposed to air. In water free from oxygen, carbonic acid, and chlor- 
ides, pure iron can only rust by decomposing the water itself, forming 
a crust of ferrous oxide which protects the surface, and liberating 
hydrogen. If oxygen be present, the ferrous oxide rapidly turns to 
red ferric hydrate, still giving a protective coating. But if carbonic 
acid be also present in excess, it dissolves the ferrous hydrate as ferrous 
bicarbonate, which in turn is oxidised to ferric hydrate, and the car- 
bonic acid is again free to act on the iron, until the whole of the iron 
is corroded and the ferric hydrate has deposited as an ochreous sedi- 
ment, leaving the water almost free from iron. The action is hastened 
if the iron contains other metals, through electrolytic action. Chlorides 
of sodium, calcium, and magnesium are also partially decomposed, 
nitrates reduced to ammonia, and sulphates changed to sulphide.^, 
which are finally precipitated by the iron. The water thus becomes 
alkaline, and if it contain organic matter, much of the iron remains 
in solution. Water is thus liable to acquire a peculiar unpleasant 
odour, due probably to hydrocarbons, and a styptic ferruginous 
taste. The iron salts not only exert an antiseptic action of 
moderate strength, but the ferric hydrate, like alumina, eifects the 
removal of bacteria, and also in the same way "mordants" and pre- 
cipitates the coleuiring and other organic matters present. If lime be 
subsequently added, or it be filtered through carbonate of lime and 
then aerated, it becomes colourless and very nearly pure. The treat- 
ment increases the amount of ammonia present, if nitrates are present 
in the original water. The hardness is not much affected. It is 

* A. Girard, Comptes Bendv-i, 1892, vol. cxiv., p. 23 i. 

t Deutsche IndiLHtriezeitung, 1 866, p. 268. 

t Disin/ectionsmittel, 1881, p. 65. § Brit. Med. Joum., 1875, p. 239. 


advantageous to filter also through peroxide of manganese to complete 
the oxidation. 

Bischof's Spongy Iron Filter and " Carferal " * are applications of 
this principle. Frankland proved that metallic iron exerts a special 
destructive action on bacteria, and pointed out that though bacteria 
prosper and multiply in sulphurous acid, cyanides, and other poisons, 
they are, on the contrary, rapidly destroyed by metallic iron.t 

Irving + causes the water to flow over metallic iron cascades, so as 
to be at once exposed to the action of the metal and of air ; he then 

Anderson has several patents for the agitation of water with scrap 
iron or filings, or with spongy iron reduced from native oxides by 
heating with carbon. In Patent No. 5,496, 1884, he suggests the use 
of revolving cylinders, so that the iron continually falls through the 
water, which passes in a slow current. § Nunn forces in air by per- 
forated pipes under pressure. |1 An elaborate apparatus, with grids 
and special means for cleaning the metallic surface, has also been 

Bischof ** agitates sewage with spongy iron, allows it to subside, and 
then assists the separation of the iron by aeration. 

The water of the River Severn at Worcester has been purified in 
this way by agitation with metallic iron. ft 

Several patents do not reduce the oxide to the metallic state, but to 
the lower oxide, re304. It must be remembered in the use of iron 
that the metal itself cannot be in contact with the water, or there 
would be the inevitable unpleasant taste and odour mentioned above. 
The purification is due to the oxides, which act as carriers of oxygen 
from the air to the organic matter present, and the core of metal is 
intended to act as a i-eservoir of fresh oxides. 

Magnetic CarbideW consists of iron ore, coke, and sawdust heated 
together at a red heat in a gas muffle so as to form the oxide Yq.^0^. 
The product is then extracted with dilute hydrochloric acid to remove 
lime, kc. 

Magnetic Spongy Iron as used for filters is made from carbonaceous 
iron-stone (black band) by heating it in closed vessels until all vapour 
ceases to be evolved.§§ It is also used for sterilising air|||| and for 

* Patent No. 12,392, 1892. Joum. Soc. Chem. Ind., 1893, p. 539. 

t Letter to the Engineers of the Municipal Council, Paris, 1881, p. 67 of their 

t Patent N'o. 8,056, 1884. § See also Patent No. 10,706, 1889. 

II Patent No. 4,619, 1891. H Patent No. 14,735, 1891. 

*• Patent No. 3,461, 1887. tt Trans. San. Institute, 1892, p. 309. 

tt Rimmer, Patent No. 8,357, 1887. §§ Candy, Patent No. 1,793, 18i6. 

nil Angell and Candy, Patent No. 14,999, 1887. 


precipitating sewage. In a later patent iron pyrites are roasted in air 
and steam, the evolved gases (containing sulphurous acid) passed over 
ferric hydrate, mixed with bauxite (jiative alumina) and the residue 
lixiviated with water. The insoluble portion is then roasted with 
coal tar, &c., short of the metallic state, crushed, and used with the 
solution for sewage precipitation.* 

Carferal (an abbreviation of carbon-ferrum-alumina), already men- 
tioned, is similar. 

Rusty scrap iron mixed with peat or wood-charcoal has been 
protected by Cox and Cox t for the treatment of sewage. 

Ferrous Sulphate, FeSO^, 7H2O, occurs in green crystals, soluble 
in 1*6 parts of water. 

All ferrous salts absorb oxygen from the air, becoming converted 
into basic ferric salts which deposit as a rusty precipitate, and acid 
ferric salts which remain in solution. Hence they act as reducing 
agents. Owing to the formation of iron moulds, the iron salts are 
inapplicable for the disinfection of clothing, &c. They deodorise fetid 
liquids by absorption of ammonia and sulphuretted hydrogen, but at 
the same time form a black coating of ferrous sulphide, which slowly 
passes to brown basic ferric sulphate by absorption of oxygen. This 
ferric coating can again absorb sulphuretted hydrogen, and again be 
oxidised, and thus acts as a kind of perpetual deodorant. J 

Virchow has pointed out one of the inconveniences of iron salts. 
The volatile fatty acids, butyric, valeric, &c, which cause a part of 
the offensive odour of putrefaction, are commonly combined with 
ammonia. When iron salts are added the fatty acids are set free or 
turned into unstable iron compounds, so that the immediate effect 
of the projection of sulphate of iron into latrines is often an augment- 
ation of the fetor; this soon decreases, but usually reappears after 
a time.§ The same result would accrue on adding almost any acid 
or acid salt, and thus, as well as for other reasons, it is necessary 
to supplement the use of an acid or treatment with an iron salt by 
lime. Lake,|| proposes "iron salt, then lime, then filter;" Lockwood,1I 
'* iron salt, then hot milk of lime ; " and Conder ** uses ferrous 
sulphate both for the treatment of water or sewage and for the pre- 
servation of meat. 

Deposits of sulphide of iron in sewers may be a source of danger, 
since they are liable to produce sulphuretted hydrogen on the influx 
of any acid liquid. An oxidising disinfectant like chlorine would, 

• Candy, Patent No. 18,598, 1892. + Patent No. 1,259, 1886. 

t Kuhlmann, quoted by Vallin, p. 62. § Ibid. , p. 63. 

II Patent No. 3,953, 1884. % Patent No. 2,560, 1892. 

•* Patent No. 6,459, 1885. 



however, convert it into a sulphate and allow of its removal. All 
reducing disinfectants are open to the following objections; (1) they 
permit the reduced organic matters to be oxidised again by the air; 
(2) they are themselves in great part at first wasted by the free 
oxygen of the air and the water; (3) unless kept out of contact with 
air they lose strength more or less rapidly by absorbing oxygen; 
(4) the anaerobic bacteria are mostly reducing in their action and 
flourish readily in surroundings deprived of oxygen, whereas free 
oxygen is capable itself of killing them and destroying their food. 
With many organic substances, e.g., tannin, iron salts produce a 
black colouration and hence the French administration have pro- 
hibited the use of iron salts where pavements or gullies can be dis- 
coloured. In December, 1879, a Paris manufacturer recovered heavy 
damages from a Disinfecting Company for stains on his materials 
caused by careless disinfection by ferrous sulphate. Tallin significantly 
adds (p. 755), "It seems that the disinfection was proved by the 
evidence to have been quite insufficient whatever may have been the 
quantity of sulphate of iron employed." Pettenkofer states that for 
the disinfection of discharges it requires 25 grammes of ferrous sul- 
phate per head per day, or about 1 in 400 on the quantity of excreta. 
The strength of solution recommended is 28° Baume or about 37 per 
cent, of crystallised ferrous sulphate. 

Miquel classed ferrous sulphate as "moderately antiseptic," 11 
grammes per litre being required to prevent putrefaction of beef 
juice. This amount agrees closely with that proposed by Grace 
Calvert, who advocated the use of a 1 per cent, solution. 

The memorandum of the British Local Government Board, 1892, 
says — "A substance generally available in the removal of filth from 
privies and ashpits, and for application to foul earth and the like, 
is sulphate of iron (green copperas), either in a strong solution made 
by stirring the crystals with 5 or 10 times their bulk of hot water, 
or in the form of powder, to which form the crystals may be readily 
brought after desiccation.* This agent should be used in quantity 
sufficient to destroy all odour f and in the removal of filth accumula- 
tions it should be well mixed with successive layers of the matter 
to be removed. It cannot confidently be stated that either the iron 
salt or any available substance will effect a true disinfection of such 
masses of filth as are here in question." 

*6y this they lose water of crystallisation, which is nearly half (44 per cent.) 
their weight, and become rather less easily soluble. If overheated a great loss 
woald occur from oxidation and production of a basic salt. So that desiccation 
is of very doubtful expediency. 

tSee Virchow's remark, ante, p. 118. 


The Society of l\redical Officers of Health have also recently 
approved of ferrous sulphate for excreta. 

The Belgian Government disinfect dejecta with ferrous sulphate 
(or 2 or 3 per cent, carbolic), obtaining a supply by suspending a 
bucket containing 50 kilogrammes in a cask full of water. 

Germany, Austria, Sweden, and the United States do not officially 
use it. In Jena a mixture of 1 part of the salt to 2 or 3 of ground 
gypsum (which absorbs ammonia) is sprinkled oft the drains,* and is 
called "Liider and Seidloif's Disinfecting powder." Candy f uses for 
sewage the waste iron filings from aniline works dissolved in hot 
sulphuric acid. This would give an acid mixture of ferrous and ferric 
sulphate. KiddJ mixes ferrous sulphate 20 parts, with lime 4 parts, 
and uses the wet precipitate with 1 pint of refuse soap for sewage 
treatment. Bog iron ore without lime has also been suggested as 
a mechanical precipitant, possibly acting as a feeble carrier of oxygen, 
and a partial deodorant. 

Harvey § proposes soda waste 1,000 lbs. to 1 million gallons of 
sewage, then adding 62'5 gallons of burnt pyrites dissolved in hydro- 
chloric acid, or practically a mixture of ferrous sulphate with some 
ferric chloride. He states that the specific gravity of the solution is 
1*275, and that the sewage is rapidly and effectively clarified. But 
the effluent would be acid. Both and Lex || show that a mass of faeces 
treated with a very strong solution of ferrous sulphate developed fungi 
in abundance. 

Ferric Sulphate, Fe.2(S04)3, in solution is brown and strongly acid. 
It is moderately antiseptic, an imperfect deodoriser, and is open to the 
same objections as ferrous sulphate, except that it is not a reducing 
agent. It has recently been proposed as a cheap non-poisonous disin- 
fectant. It gives precipitates with nitrogenous organic matters, and 
coagulates albumen. Fresh urine treated with ferric sulphate yields a 
precipitate containing 5-34 per cent, of nitrogen and 12*42 per cent, of 
phosphoric acid. It may be conveniently obtained by the action of 
sulphuric acid on burnt pyrites, but the solution would contain also 
some ferrous sulphate in most cases. It has been manufactured into 
briquettes, Fe.2(S04)3, OHoO, of a greyish pink colour, which are very 
dense, and as compact as cement if mixed with plaster of Paris. 
Phenolic briquettes are also made from 100 parts of ferric sulphate, 
GO per cent., 5 parts phenol, and 16 of water. 

Sacre and Grinishawll use the ferric hydrate obtained as a waste 
product in the purification of zinc chloride as a cheap source for the 

* Reichardt's Disinfection, 1881, p. 100. t Patent No. 19,587, 189*2. 

X Patent No. 16,060, 1885. § Patent No. 6,994, 1889. 

I! Handb. d. Militar., vol. i., p. 524. ^ Patent IS'o. 17,911, 1891. 


production of ferric chloride or sulphate, to be used to purify 

Wohanka and Kociau, of Prague, propose adding to ferric sulphate 
(brown iron ore and sulphuric acid) lime, and afterwards water-glass 
(silicate of soda). The patentees claim that such treatment destroys 
the organisms in sewage. A clear effluent is obtained after filtration.* 

Wolff grinds puddle slag containing 54 per cent, of iron with acids, 
then adds chalk, and mixes with sewage. The sludge gives a manure, 
and the effluent is stated to be clear and not to putrefy for months. 
One cubic metre of waste water {e.g., from paper works) requires only 
a few grammes.! 

It is to be regretted that ferric sulphate, which could be so cheaply 
made, is not of the value that the above statement would imply. It 
does not kill bacteria unless it be of impractical strength. 

Ferric Chloride, FcoCIq, is very soluble in water, giving a yellow or 
brown strongly acid solution. In properties it resembles ferric sul- 
phate, but is said to be slightly more powerful. It is a feeble oxidising 
agent, absorbing ammonias and sulphuretted hydrogen. It checks 
fermentation and the growth of bacteria without killing them, unless 
it is concentrated. | With excreta it is apt to cause a very nauseous 
odour. Wernicli gives a favourable account of its action as a precipi- 
tant : — " Putrid and offensive material containing ammonium carbonate 
cause a precipitate of iron oxide which carries down the suspended 
matters; the supernatant liquid is clear, and both it and the precipitate 
are inodorous, the sulphuretted hydrogen being removed as ferrous 
sulphide and free sulphur, and the ammonia turned into ammonium 
chloride." § 

Sternberg says that it quickly paralyses the power of infection, 
which, however, after a time revives.|| 

Drs. Hofmann and E. Frankland, in a report to the Metropolitan 
Boai'd of Works in 1859, recommended chloride of iron for the deo- 
dorisation of sewage, and found that to deodorise 7,500 gallons, l gallon 
of perchloride of iron was equivalent to 3 lbs. of chloride of lime or 
1 bushel of lime. The first of these kept the tank free from odour for 
upwards of nine days, whilst the lime treatment broke down on the 
third day, and that with bleaching powder after five days. 

Vallin condemns it as a disinfectant.H It has no official recognition. 
Nevertheless two English patents were taken out for its use iu 1892, 
Nos. 13,316 and 15,235. 

* Patent No. 278, 1887. t Wolff, Dingl. Pol. Joum., vol. cclxiii., p. 484. 

+ Frankland and Ward's Second Report, Joum. Sac. Chcm. Iml., 1893, p. 1,052. 
§ DiHin/ection'a Lehre, 1882, p. 180. 
II Nat. B. o/Beahh, U.S.A., 1881, vol. cxL, p. 4 H Loc. cit., p, 65. 



The metal is at present commercially unavailable for water purifi- 
cation; it would act like metallic iron, but with greater energy. 
" Ferro-manganese," an alloy containing up to 80 per cent, man- 
ganese, and "Spiegeleisen" might be useful substitutes for iron in 
water i)urification. 

Peroxide or Dioxide of Manganese, MnOg, found native as Pyrolusite, 
does not yield its oxygen to organic matters at the ordinary tempera- 
ture. The precipitated peroxide (hydrated) is also sluggish. Candy 
■asserts* that "sewage may be purified by agitation in a suitable 
vessel with granular manganese dioxide, the average time of contact 
being about five minutes." This statement seems to require confir- 
mation, as it is difficult to understand how any purification other 
than mechanical can take place under these conditions. If it be 
heated strongly in closed vessels with carbon, a mixture of the 
excess of carbon with lower oxides of manganese or perhaps the 
metal itself is obtained. By this treatment the carbon is at the 
same time purified and deprived of its hydrogen and any tarry 
products which may be present. Such a preparation is much more 
active as a carrier of oxygen than the similar one made with oxides 
of iron (see ante, p. 117). Moreover it does not yield metal to 
the water, as iron does. "Manganous cax'bon" was introduced by 

This oxide when heated with hydrochloric acid is the ordinary 
•source of chlorine — 

MnOz + 4HC1 = MnCIa + 2H2O + CU. 

As mentioned under the halogens, if it be heated with a chloride, 
bromide, or iodide and sulphuric acid, it gives off the whole of the 
<!hlorine, bromine or iodine. Such mixtures have been much used for 
disinfecting rooms {ante, p. 57). 

Manganous Salts. — Both the manganous chloride, MnClo, and the 
sulphate, MnSO^ are slightly antiseptic. Miquel calls the former a 
weak antiseptic since he required 25 grammes of it to prevent growths 
in a litre of beef tea. Page considers that these salts are good disin- 
fectants, but adduces no experiments in support of his conclusion. 

Slater, Page, and others t proposed manganese chloride, and sul- 
phate for sewage treatment, either alone or mixed with salts of 

Chloride or sulphate of iron mixed with vitriol or hydrochloric acid, 
manganese dioxide, or hydrated ferric oxide, and ground bauxite has 

* Patent No. 15,391, 1891. . + Patent No. 3,973, 1886. 


been recently advocated for sewage treatment.* It is a mixture of 
iron, manganese, and aluminium salts, possessing no apparent ad- 

Manganous salts as such may be excluded from the list of useful 
•disinfectants, antiseptics, or even deodorants. They do not oxidise 
on exposure to air, and, therefore, do not act as carriers of oxygen. 
Even if lime be added, so as to precipitate manganous hydrate which 
is re-oxidised by air, the action in presence of much water and organic 
matter is unsatisfactory, and the expense would be great. 

Manganates and Permanganates. — The manganates of the alkalies 
are dark-green, unstable salts ; they are produced by fusing potash or 
soda or their carbonates with manganese dioxide in the presence of 
air, or with an oxidising agent, such as potassium or sodium chlorate 
or nitrate. Impure sodium manganate, NaoMnO^, with much sodium 
chloride, is known as " Condy's Green Fluid ;" it also contains some 
permanganate (if barium chloride be added, the manganate is preci- 
pitated, and the crimson permanganate is left in solution), and is 
strongly alkaline fi*om excess of the base. It is a cheap oxidiser, but 
as being impure and of varying strength, is much less used than the 
permanganate. It spontaneously gives up 1 atom of oxygen with 
great readiness, turning brown and turbid from the precipitation of 
the hydrated peroxide thus — 

2Na2Mn04 + 6H2O = 4NaOH: + 2Mn(OH)4 + Og. 

If a dilute acid be added, even carbonic, it changes its colour to 
•crimson, forming the permanganate, while hydrated peroxide is again 
precipitated thus — 

SKjMnOi + 2II2SO4 = KaMnjOg + Mn(0H)4 + 2K2SO4. 

The decanted solution is nearly neutral, consists of permanganate 
and sulphate, and is known as "Condy's Red Fluid." If evaporated 
it yields crystals of permanganate, which are purified by recrystallisa- 
tion. An application of this reaction is made in J. C. Stevenson's 
patent f " acid sodium sulphate, ground with crude sodium manganese, 
gives permanganate when dissolved." 

Stevenson and Tatters I use dry sodium manganate 6 parts, bleach- 
ing powder 3 parts; this yields a mixture of manganate, hypochlorite, 
and chloride. Duprd and Hake § propose " a manganate with mag- 
nesium sulphate or kieserite, calcium sulphate, zinc sulphate, or boric 
acid. The manganate and one of these reagents are mixed in a dry 
fine state of division." 

Manganate of soda introduced into sewers in sufficient quantities 

* Chem. Trades Jmm., Feb. 25, 1893. t Patent No. 2,739, Feb., 18S5. 
t Patent No. 381, Jan., 1887. § Patent No. 4,283, 1887. 


at different points, not only destroys organic impurity, but prevents 
any noxious smells, and by further treatment at the outfall, the 
effluent matter may be rendered "perfectly odourless, so as to be 
discharged into streams with safety. Being strongly alkaline, it 
disengages ammonia, which should be removed at the outfall by acid 
treatment. Manganates have been employed by the Metropolitan 
Board of Works, and by the London County Council, with fair 
results. Vallin, on the contrary, asserts that sodium manganate is 
almost inert. The amounts of available oxygen in two commercial 
tiuids acidified by sulphuric acid, as determined by Allen in 1872, 
were — 

Green. Crimson. 

Available oxygen in grammes per litre, 3'883 3921 

Potassium Permanganate, KoMn.,Og, occurs in dark-red needles, 
which are permanent in the air, and easily soluble in 15 or 16 parts 
of cold water, giving an intensely crimson solution. In contact with 
organic matter, when acidified with sulphuric aciiJ, it can furnish 
5 atoms of oxygen — 

KaMnaOg + 3H2SO4 = K2SO4 + 2MnS04 + SHjO + 50. 

The solution should remain clear. If the acid be insufficient, a 
brown precipitate of hydrated peroxide falls, and then only 3 atoms of 
oxygen are liberated — 

KjMnoOg + HaS04 + SHjO = K2SO4 + 2Mn{OH)4 + .30. 

The progress of the reaction can thus be watched by the loss of 
colour of the permanganate, the final point, when excess is reached, 
being sharply indicated by the persistence of the pink colour of the 
permanganate. Its disadvantages are : — 

1. It leaves a brown stain on fabric?, and if concentrated it corrodes 

2. Like chromic acid, it must first expend itself in oxidising sul- 
phuretted hydrogen, nitrites, ferrous salts, and most organic matters, 
before attacking organisms, which are so resistant to it that Koch 
states * that it is applicable only in concentrated solutions (5 per cent.) 
Miquel puts it in the third class of disinfectants, requiring 3"5 grammes 
to sterilise 1 litre of beef tea. Calvert, on the other hand, found that 
1 in 125 "prevented animalcules in beef juice and albumen for six 
days." Hankin considers it a specific for cholera bacilli, f 

3. Not being volatile, it can only act locally. Condy in 1859 
proposed its employment for air-disinfection by hanging up sheets 
saturated with the solution, by sprinkling walls, and by exposing 
layers of it in dishes in infected rooms. By such procedure a large 
quantity of air must escape contact with the liquid. 

* MUlh. a. d. hats. Ges., Dec. 3, 1881. t Brit. Med. Jturn., Mar. 16, 189.5. 


The solid when treated with strong sulphuric acid gives off ozone, 
but the reaction is a violent one, and is dangerous in inexperienced 

Deniarquay spoke favourably of it for surgical use in a solution 
containing 1 in 1,000, as disinfecting very well, and as hardly irritant. 
But its action is ra[)idly exhausted, and it does not prevent the secre- 
tions from retaii;iing their virulence, and Vallin is of the opinion that 
it is of more value as an immediate deodorant than as a destroyer of 
virus.* This statement has since been corroborated by Blyth,f and 
by Klein.J 

4. Permanganates do not absorb ammonia, and do not attack urea 
nor fatty acids. 

Condy and Mitchell's original patent has long expired. In 1877 
the former invented a very ingenious contrivance with vertical threads 
hanging close together in a ring, down which a solution of perman- 
ganate trickled from a circular basin above to a similar one below. 
This, of course, could be applied to other disinfectants ; with volatile 
ones it would be more effective. 

Among the numerous patents covering the application of perman- 
ganates for disinfecting purposes are : — Reidemeister of Magdeburg,§ 
"Small quantities of potassium permanganate and peroxide of hydrogen 
are added to water when a bulky precipitate forms, carrying down 
all suspended matter and the smallest organisms, while oxygen is 

Tweedie and Hartin's " Crimson Salt " || is 1 part of potassium 
permanganate, 8 of potash alum, 1 of borax, 6 of sodium chloride. 
H. B. Condyll proposes the use of the aluminium salt " In 1,000 parts 
by weight of a 33 ]>er cent, solution of aluminium sulphate, dissolve 
53 of potassium permanganate by heat. On cooling, i)Otash sulphate 
alone crystallises out, leaving permanganate of alumina and excess of 
aluminium sulphate in solution." 

Lumps for closets containing the following mixture have been 
proposed : — Boric acid 10, salicylic acid 10, potassium pennanganate 
40, potassium or sodium silicate 40, made into a hard mass.** Meyer 
uses " Dry powdered barium permanganate 25 parts, to sodium bi- 
sulphate 16 parts, mixed in the dry state; an inert body like bariiim 
sulphate may be added to give bulk. If sufficient water be added to 
form a thick syrup, ozonised oxygen will be evolved." ft 

* Vallin, TraiU, pp. 325-328. 

t " Studies of Disinfectants by New Methods," Proc R. Soc., 1886, 
t Stevenson and Murphy's Ilyffiene, 1893, p. 01. § D. Patent, July, 1882. 
II Patent No. 9,538, June, 1884. H Patent No. 10,015, 1S84. 

*• J. Soc. Chem. /ud.,.1890, p. 98, tt Patent No. 16,463, 1S3S. 


Hamilton* fuses potassium chlorate, manganese dioxide, and 
potash, saturates the solution with carbonic acid, and crystallises. 
This is simply an old method of 'making permanganate. He then 
mixes it with borax. 

"Taylor's Roylat Disinfector" is an ingenious contrivance for 
liberating the liquid in cisterns automatically. Stoneware bottles 
are filled with permanganate and hermetically closed, with the ex- 
ception of a small glass tube which reaches to the bottom. The bottle 
is inverted and placed at the bottom of the cistern. When the latter 
empties some strong solution flows out.f 

" Condy's powder " contains a small proportion of alkaline perman- 
ganate and has no smell. | 

Disinfecting tablets or blocks have been proposed by Thornton.§ 
They are "prepared by mixing potassium permanganate or other 
disinfectant, paraffin wax, sulphate of calcium, or any other suitable 
cement, with some absorbent material, such as asbestos, cotton yarn, 
pumicestone, cinders, &c. 

" Permanganate of potash is mixed with plaster of Paris or other 
cement or plaster, and cast into bricks or balls or into perforated tin 
cases, the object being to economise the permanganate."! 

One or two patents propose to recover the manganese or iron oxides 
precipitated in the sludge in sewage treatment, by pressing the latter,, 
adding more ferric or manganese oxide, if necessary, heating in a 
closed retort, utilising the ammonia and evolved gases, cooling out of 
contact with air, and using the mixture of carbon with metallic oxides 
as a filtering medium. U The process, however, is not economical, as 
there is so much water to remove, and the product is of very inferior 

M'Dougall calculated that "at the commercial price of Condy's fluid 
in his time, it would cost £10,400 per annum to disinfect with per- 
manganate the typhoid stools of a hospital having an average of 30 
cases." Crystallised permanganate has since been much cheapened, 
but the cost yet remains sufficiently formidable to prevent its ex- 
tended use, and, as already pointed out, its applications are somewhat 

•Patent No. 6,571, 1887. 

t Cy., "A similar Method for Cisterns," by B. S. Proctor, Chemist and Druggist, 
April 28, 1894. 
X Lancet, 1887, p. 683. § Patent No. 17,421, 1891. 

II M. Syer, Patent No. 11,049, 1892, 
IT Wilson, Patent No. 17,275, 1891, and others. 


METALLIC SALTS {continued). 

Aluminium Salts : Use in Sewage Precipitation — Alums — Aluminium Chloride 
— "Chloralum" — Acetate — Sulphites — General Character of the Salts. 
Chromium : Chromic Acid — Potassium Bichromate. Arsenic : Arsenious 
Acid — Arsenites — " Paris Green " — Arsenic Acid — Prohibition in France. 
Lead and its Salts : Nitrate and Acetate. Mercury : Oxide and Nitrate 
— Corrosive Sublimate; its power as a Disinfectant— Applications — Iodide 
— Mercuric Iodide Soaps — Cyanide — "Zinc Mercuric Cyanide" — Objections 
to Mercury Compounds — Organic Mercurials. Tin: Stannous Chloride. 
Bismuth: Subnitrate — "Dermatol." Silver: Nitrate of Silver — Osmic 
Acid. General Remarks on Disinfectants. 


The soluble salts of aluminium generally are powerfully astringent, 
acid, styptic to taste, and in solutions of moderate strength are not 
poisonous. They also produce no stain on fabrics, do not act upon 
metals, and are iriexpensive. On addition of lime or ammonia they 
give a bulky flocculent precipitate of hydrated alumina, carrying down 
mechanically with it not only the solid matter in suspension and any 
germs that may be present, but also much of the dissolved organic 
matter, forming more or less definite combinations analogous to the 
"lakes." They have therefore been most extensively tried for sewage,, 
both alone and with iron salts, lime in most cases being added. The 
effluent by this treatment is in most cases found to be clear, nearly 
colourless, apparently sterile, and deprived of most of its odour^ 
Unless an equivalent of lime or ammonia is present, the effluent is 
acid and has an injurious influence on fish. The precipitate or "sludge"" 
should include all the phosphates, most of the nitrogenous matter, and, 
since it contains no poisonous disinfectant, be available commercially 
as manure. 

The antiseptic power of the alums and of aluminium sulphate, the 
forms most commonly used, is only slightly greater than that of the 
sulphuric acid they contain, and most authorities are of the opinion 
that when these salts are used in sewage treatment the germs are not 
entirely removed; a few escape precipitation and soon commence to 
multiply afresh ; consequently the effluent again becomes foul, and 
on being diluted by passing into rivers, is capable of contaminating 
immense volumes of water. That the whole of the river is not polluted 


is due to the fact that " purified " sewage does not readily mix with 
ordinary water, but flows on for long distances in a separate stream. 

The "sludge" also becomes quickly offensive in warm weather. 
Eepeated attempts to utilise it as manure, by straining, pressing, 
drying, and even fortifying with phosphates, &c., have hitherto met 
with only partial success. 

Attempts to burn it for cement, utilising the ammonia and other 
^ases evolved, have also been made. The great difficulty is the 
removal of the water, which gives in drying, and still more in burning, 
offensive vapours. 

The following is a brief summary of the processes that have been 
tried for sewage precipitation, of which many involve the use of 
aluminium salts : — 

1. Lime Process. — The First Report of the Elvers Pollution Commis- 
sion, vol. i., p. 52, pronounced it a failure. 

2. Lime and afterwards Ferric Chloride. 

3. Ferric Chloride alone. — Too expensive.* 

4. Zinc and Manganese Salts. — Unsatisfactory. 

5. M. and C. Process, 1875. 

6. General Scott's Sewage Cement process, 1872. Lime and Clay. — 

7. mile's Method. — 100 lime, 6 tar, 12 calcined magnesium chloride 
(mother liquor of sea water). Expensive. Sludge useless. Water 
deodorised, but bad. 

8. Black Ash ^Vaste.J — This material must be free from calcium 
sulphide — i.e., must be old and oxidised to thiosulphate. Its use has 
not met with any degree of success. 

9. Jili/th's. — Superphosphate of magnesium, to add to the value of 
the sludge as manure. 

10. llolden's. — Ferrous sulphate, lime, and coal-dust or clay. 1868. 

1 1. David Forbes' PJiosphate Method. — Described under "Acids" (p.97). 

12. Whitthread's Patent, 1872. 

13. Bird's Process. — Crude aluminium sulphate, obtained from 
pulverised clay and strong sulphuric acid, which are heated together^ 
and the mass allowed to settle, and then filter through coke. The 
•effluent is acid. 

14. Stothert's. — Aluminium and zinc sulphates and charcoal, then lime. 

15. The well-known A. B.C. Process. — " Alum, blood (freshly drawn), 
clay, charcoal, some compound of manganese, and various other ingre- 
dients in smaller proportions." Tried on the large scale at Leamington 
in 18G7. Unfavourably criticised by the Eoyal Commission of 1870. 

* Second Report of Setoage of Tovms Commission, pp. 17 and 72. 
t Hanson, Roy. Comm. of Metr. Sew. Discharge, vol. xi., p. 97. 


IG. Anderson's. — "The sewage, after subsidence, is agitated with a 
saturated boiling solution of crude aluminium sulphate, then milk of 
lime, then filtered through soil into the river." The effluent is not 
pure, the cost is great, and the manure of little value (Corjield). 

17. Lower Thames Valley, 1884. Aluminium and Ferrous Sul- 
2}}uites, and Lime. — Rejected by a Committee of the House of 

18, Wimbledon Process. — Spence's " aluraino-ferric " (composition, 
Al.jOy, soluble 14 per cent.; FeoO.,, 0*75; SO.j, 33-81; free acid, none; 
water, 51 "44) is used with lime. In very hot weather, sodium man- 
^anate is used in addition, to prevent the setting up of secondary 
fermentations, and the production of offensive odours when the sewage 
is applied to the land. The manganate is dissolved in warm water, 
and is added to the clarified sewage in the settling tanks in the pro- 
portion of about 2 grains per gallon. Nearly every known reagent 
has been tried at Wimbledon, but up to the present the above has 
been found the best. 

During the Royal Commission to investigate the conditions of the 
Metropolitan Dis(;harge,t Mr. Dibdin pointed out that it is possible 
to thoroughly deodorise the sewage by means of potassium perman- 
ganate and sulphuric acid (giving ozonised oxygen) either before or 
after the removal of the suspended matters by precipitation. Large 
quantities of sodium manganate are now used for this purpose, which 
salt seems at present to be the only one of value, but the cost is 
considerable. Ferrous sulphate also remains in favour. Obviously 
the two cannot be used together, as one being an oxidising and 
the other a reducing agent, they would destroy one another. 

Parkes and Corfield summarise as follows: — " All to a certain extent 
purify the sewage and prevent the pollution of rivers, chiefly by 
removing the suspended matter, but they all leave a large amount of 
putrescible matter in the effluent, and at least all the ammonia." IMost 
of the phosphoric acid is also precipitated, and in many of the processes 
the hardness of the water is increased. 

A multitude of patents exist which have been taken out for slight 
variations in the use of blast-furnace slag, clay, or shale alone, either 
raw or burnt, or the products of their treatment with acids, yielding 
crude salts of aluminium and iron, with lime, peat, charcoal, coke, «kc. 
One or two examples may be noticed : — In Patent No. 2,068, 1882 : 
" Cannel coal broken small with 10 per cent, of alumina, preferably as 
aluminous clay or brick earth, coked in a kiln," is used as a deodorant. 
In Patent No. 13,7G1, 1885 : "Native aluminium phosphate dissolved 

• See a paper on Sewage disposal, Soc. Med. Off. of Health, 1884-5, by Dr. 
Stevenson. t Vol. xi., p. 142. 



in acid, and the same substance dissolved in soda are added succes- 
sively to the sewage. The acid and alkali neutralise one another, and 
the whole of the phosphate is precipitated." Unfortunately, phosphate 
of alumina is so soluble that it is the least useful phosphoric salt for 
manure. Similarly it is proposed to add sodium aluminate to acid 
aluminium sulphate.* 

Kruger,t after stating that Bolton, Hueppe, and Frankland's experi- 
ments are not entirely exclusive, details his examination of the action, 
of clay, carbonate of lime, kieselguhr, alumina, brick-dust, charcoal^ 
coke, and sand, on sewage. He points out that finely-divided, chemi- 
cally inert substances, when introduced into water, take down with 
them the greater part of the bacteria present. The action is more 
intense the slower, within certain limits, that the deposition takes- 
place, and the greater the quantity of precipitant supplied. 

He gives another series of experiments with chemical agents, in- 
cluding aluminium sulphate. The sterilisation is far greater when, in 
addition to the merely physical deposition, a chemical precipitation 
supervenes. In the purification of sewage water, therefore, preference 
should be given to chemical treatment, and inert substances should 
merely be regarded as mechanical aids. 

Leeds 1 states that half a grain of alum per gallon reduced the 
micro-organisms from 8,100 in 1 c.c. to 80. 

Y. and A. Babes found that 02 gramme per litre after twelve hours- 
carried down all the microbes from a water containing 1,200 per c.c.^ 
and the supernatant liquid was sterile. The sediment also contained 
from 20 to 100 living bacteria, whereas the untreated water had 1,500 
to 6,000.§ 

A report by Lepoins, published by the Frankfort Commission on 
Sewage, 1891, states as follows : — "The eflfect of chemical precipitation; 
is not so greatly superior to the purification obtained by simple de- 
position in tanks, as to warrant the adoption of any of the above 
processes in preference to simple mechanical treatment." 

The result of trials at the St. Lawrence Experimental Station In 
Massachusetts has shown that "a mixture of lime and aluminium 
sulphate has little to recommend it." 

Sir R. Rawlinson || remarks, " To disinfect the sewage of the 
Metropolis would cost millions per annum, and, according to Dr.. 
Parkes, the most powerful disinfectants would not give safe results. 
* Clarification ' may be accomplished temporarily by chemicals, but 

* Maxwell Lyte, Patent Nos. 900 and 6,054, 1885. 

+ Zeit. f. Hyg., 1889, p. 86. X Potable Water, Boston, 1891, p. 86. 

§ Centr.f. Bakleriol., 1892, vol. xii., p. 132, 

II Joum. Soc. Arts, vol. xxxviii., p. 65. 


will not then produce permanent purity. It will cost £1,500 to 
£3,000 for each million gallons per diem, and even the less amount 
will reach £225,000 per annum for the Metropolis, while expenses 
will raise this half a million." Notwithstanding, patent 24,080, 1892, 
proposes " to sterilise water without filtration by adding alum, 1 to 2 
per 1,000, and leaving to settle for twelve hours." 

At Glasgow aluminium sulphate and lime, with filtration through 
coke, gravel, and sand, and subsequent aeration is employed before 
the water effluent passes into the Clyde. 

Aluminium Chloride, AlgClg, occurs in white crystals, very sol- 
uble in water, strongly acid, non-poisonous, but powerfully astringent 
when diluted ; it absorbs ammonia and compound ammonias, but not 
sulphuretted hydrogen, therefore it is only a partial deodorant. It 
is more antiseptic than the sulphate, and still more than alum. 
Miquel gives the minimum for sterilising a litre of beef tea as Al^Clg 
1'4, potash alum, 4-5 grammes, as compared with mercuric chloride 
0-07, copper sulphate 0-9, and zinc chloride 1"9, so that its behaviour 
is intermediate between copper sulphate and zinc chloride. It is a 
good local disinfectant when strong. 

Slater and Stevens* dissolve "Gibbsite" or any aluminium com- 
pound containing, a considerable proportion of hydrate of alumina in 
hydrochloric acid. The acid solution is used for sewage, preceded by 
lime, with the addition of clay and charcoal ground up together.! 
Again, J Slater and the "Native Guano Company" add " clay, crude 
aluminium chloride, and other substances to sewage." The use of slag 
and hydrochloric acid have also been patented by Slater.§ In another 
patent crude aluminium and iron sulphates from shale are mixed with 
calcium chloride, yielding aluminium chloride and calcium sulphate, 
the latter being used for manure. 

Chloralum was the title given to a disinfectant much advertised in 
England for some years, but now f^lmost disused. Fleek, of Dresden, 
states that it contains chlorides of aluminium, lead, copper, iron, and 
calcium of various amounts. 

Wanklyn || pronounced it to be a deo<lorant superior to chloride of 
lime. M'Dougall by experiments maintained that it arrested putre- 
faction and prevented the growth of organisms more than other 
antiseptics. He recommended it for washing infected matters, for 
disinfecting sewers and the soiled linen of hospitals. But O'Neill's 
experimentsIT tended to show that neither chloralum nor chloride of 

* Patent No. 15,810, 1884. t See also Patent No. 16,592, 1894. 

t Patent No. 17,453, Oct., 1S90. § Patent No. 12,830, 1884. 

\\ Brit. Med. Journ., "Action and Relative Value of Disinfectants," 1873, 

p. 275. IT Army Med. Report, 1871. 


aluminium itself arrested putrefaction. " Even on adding 1 part of 
chloralum to 2 parts of organic matter, animalcules were abundant on 
the fifth day, and a putrid odour Vas distinct on the seventh day. 
Aluminium chloride was slightly better, as the odour was delayed 
to the tenth day, with 1 part in 6 or 8. Vallin states that 
" Cupralum," a mixture of alum with copper salts, has aimed at re- 
placing "chloralum," but with no greater success. 

Aluminium Acetate has been much praised by Barow, Kuhn, 
Wernitz, and Jalan de la Croix. It would doubtless be useful for 
surgical dressings, but is unnecessary and unsafe as a disinfectant. 
Maas recommends a 2-5 per cent, solution for surgical work. 

Aluminium Sulphites have been recommended by Wade as non- 
poisonous and non-irritating antiseptics.* 


Chromic Acid, CrO.j, is a powerful oxidiser, and instantly coagulates 
albumen. It combines with a great many organic compounds, pro- 
ducing brown or yellow substances. This staining or mordanting 
action causes it to kill bacteria by an action on their envelopes. 
It i-anks with the halogens, nitrate of silver, and permanganate, in 
its special action both as an antiseptic and disinfectant. Its cost 
and poisonous and corrosive nature have excluded it from the list 
of useful disinfectants. 

Potassium Bichromate, K^Cr^O-, is similar, but less vigorous, in 
its properties. 

The earlier investigators made many experiments with these two 
agents. M'Dougall t in experiments on vaccine and other virus, 
found that 1 in 2,200 of chromic acid " prevented animalcules " 
in infusions for six days, 1 in 500 for seventy-eight days. O'Neil | 
using beef juice, states that with 1 in 120 of bichromate of potash 
*• there were no signs of decomposition in twenty-four days, with 
1 in 150 a great number of animalcules appeared on the eleventh 
day ; on the twenty-fourth day there was still no really disagreeable 
odoui'." Davaine§ found that the virus of anthrax and septicaemia 
was definitely destroyed by 1 in 6,000 (anthrax) or 1 in 3,000 (septic- 
aemia) of chromic acid. These experiments are of no real value (Klein), 
since the conditions are inexact and are not those of actual practice. 

Lanjorrois |1 to 500 cubic centimetres of urine and blood added 
5 grammes of bichromate, and found that in eight months there was 

* Pharm. Kecord, Nov. 1, 1888. t Med. Times and Oaz., 1872, p. 485. 

X Army Med. Ueport, 1872, p. 202. § Qaz. Med., 1874, p. 44. 
II Chem. Centr., CI., 1884, p. 676. 


no putrescence. He does not say whether any coagulation of the latter 
occurred. Milk with 1 per cent, of bichromate remained unaltered 
for three months. But owing to its poisonous action a bichromate 
cannot be used as a preservative. 

Kidd has patented a mixture of potassium or sodium bichromate, 
or chromic acid, with a little sulphuric acid, for disinfecting sewage. 
Even if efficient, the expense would Le prohibitive. 


Arsenious Acid, As.,0.,, is a white powder, slightly soluble in 
water (about 1 in 1,000), giving a feebly acid and almost tasteless 
solution which is yet strongly poisonous. It dissolves, however, very 
easily in alkalies forming arsenites. It is also soluble in hydrochloric 
acid as arsenious chloride, or " liquor arsenici hydrochloricus.'"' The 
latter is to be preferred as it has the additional antiseptic properties 
of a solution of hydrochloric acid. 

These compounds are deodorants, as they absorb sulphuretted hydro- 
gen and compound ammonias. 

Although arsenic is so powerful a poison to higher animals and 
insects, it has little effect on lower forms of life.* Miquel ranks 
AsoOj as '•' moderately antiseptic," requiring G grammes per litre to 
prevent growth in beef tea. 

" Gannal's solution," formerly used in France for injecting corpses, 
contained 21 grammes of As^O., and 1,000 grammes of aluminium 
sulphate per litre. Seed-corn was often sprinkled with As^O^ before 
sowing, to kill fungi and insects. Copper sulphate is much better and 
safer for this purpose. 

Potassium Arsenite, " Fowler's solution,' and Sodium Arsenite, have 
long been employed as " Sheep-dips," for killing insect parasites. 
Robertson patents the following preparation t : — " 3 of rosin, 1 of 
grease melted with 6^ tar oil (containing 25 per cent, tar acids), and 
2 of 95 per cent, phenol. Add 2 of arsenious acid dissolved in 
1^ per cent, soda-lye, or an equivalent quantity of arsenic sulphide 
may be used. The product is soluble in cold water, and has the 
properties of a simple carbolic dip and an arsenic dip, the tar acids 
coagulating the parasites, and the arsenic having a continuous 
poisonous effect on their progeny." 

Acetoarsenite of Copper, " Paris Green," contains 28-5 per cent, of 
arsenic and 32 per cent, of copper. It is insoluble, but is one of the 
best agents for killing insects on trees, sprayed over them in the pro- 
portion of 1 ounce to 10 gallons of water. 

• Frankland and Ward, Journ. Soc. Chem. Jnd., 1893, p. 1,053. 
t Patent No. 2,990, 1893. 


Arsenious Sulphide, AsgSg, dissolved in alkaline sulphides, is used 
in tanning to prevent fermentation and putrefaction. But S. Sadlou 
says * that common salt, together with an alkaline sulphide, will 
produce the same result. 

Arsenic Acid, HgAsO^, is much more soluble, and reputed to be 
more poisonous, than arsenious acid. But neither it nor the arsenates 
are of any value as germicides. Miquel states that the potassium salt 
is "very feebly antiseptic," requiring 125 grammes per litre to prevent 
growth in beef tea, while sodium arsenate is " moderately antiseptic," 
requiring 9 grammes per litre. f Loew J remarks that "the acids of 
arsenic are poisonous towards algae only in the same degree and for 
the same reason as are acetic and citric. Larvjse and infusoria live in 
a 1 per mille solution of potassium arsenate, though higher animals 

In France the use of arsenical compounds as antiseptics has been 
totally prohibited since 1876. 

Considering the ease and rapidity with which arsenic is diffused, 
and the insidious action, even of traces, in water, food, or air, even if 
it were a good antiseptic, its use should be penal in all countries. 


Lead salts absorb sulphuretted hydrogen, ammonia, and their 
derivatives, and are therefore deodorant. Measured by the amount 
required to sterilise a litre of broth, Miquel classes them as "strongly 
antiseptic," only slightly below zinc chloride, where 1*9 grammes of the 
latter is used, 2 grammes of lead chloride, or 3-6 grammes of lead 
nitrate, are required. 

Nitrate of Lead, Pb(N03).„ is the basis of a "disinfectant" long 
known under the name of "Ledoyen's liquid," composed of 1 part of 
the salt in 10 of water. M. Fermond in 1858 used it in the closets of 
the Saltpetriere, and found it was effective in removing the odour, as 
other metallic salts would be, but it had the disadvantage of being 
easily precipitated as lead sulphate, and of covering the basins with a 
black coating of lead sulphide. It is expensive, and does not absorb 
ammonia readily. It is inapplicable for wounds, on account of its 
ready absorption and poisonous effect on the system.§ 

Basic Acetate of Lead, or "Goulards' Extract," is used for burns 
and bruises, but only for its cooling qualities. 

In conclusion, lead compounds are of no value as disinfectants. 

* Der Gerber, 1891, vol. xvii., p. 284. 
t Les Organinmes, p. 289. 
i Centr.f. Agric. Chem., vol. xiii., p. 68. 
§ Vallm, D6smfectant8, 1882, p. 66. 



Mercuric Oxide, HgO, like insoluble substances generally, has no 
action by itself on organisms, but it easily dissolves in even vegetable 
acids to form many soluble, and therefore active, salts. Admixed or 
combined with phenol it has been used for a '* earbolate of mercury " 
soap, which, according to Dr. Woodhead,* is not a valuable preparation. 
Combined with oleic acid it forms a strongly anti-parasitic basis for 
ointment. Oleate of mercury is in the British and most other phar- 

Mercuric and Mercurous Nitrates are strongly antiseptic soluble 
salts, but are not used because they are caustic and are easily decom- 
posed by a large quantity of water. ** Unguentum Hyd. Nitratis " 
is a parasiticide. 

Mercuric Chloride, HgCl2, perchloride of mercury, or "corrosive 
sublimate," is probably the most powerful disinfectant we possess. 
It will be seen that the poisonous action of a great number of anti- 
septics depends on their property of precipitating albumen and other 
allied ingredients of protoplasm. For example, phenol, mineral acids, 
copper and iron salts, alum, tannin, chromic acid, all form insoluble 
compounds with ^Ibumen. Mercuric chloride possesses this property 
in a very marked degree, but the compound produced re-dissolves in 
excess of albumen. It is, therefore, necessary to have mercuric chloride 
present in excess. Mercuric chloride is soluble in 15 parts of water, 
and still more in alcohol, ammonium chloride, sodium chloride, and 
dilute acids. It is exceedingly poisonous, a dose of 2 centigrammes 
■daily soon producing poisonous effects. This almost prevents its use 
internally, and even makes its external employment dangerous. Hence 
solutions of it used for disinfection should be coloured, preferably blue. 
In the United States it is recommended to add an equal quantity of 
potassium permanganate to distinguish the solution. As to the 
efficiency of mercuric chloride, the earlier investigators gave varying 
but very high results. Bucholtz, in a comparative list of the amounts 
of different disinfectants required to suppress the gi'owth of bacteria 
in culture solutions, places mercuric chloride in the foremost place, 
and recommends a solution of 1 in 20,000.t Miquel says that a 
solution of 1 in 14,000 is disinfectant, and Sternberg 1 in 30,000. 
Koch asserts that "a single application of a solution 1 in 1,000 or even 
1 in 5,000 is sufficient to destroy the most resistant organism in a few 
minutes ; with a longer exposure it only begins to be unreliable at 
1 in 20,000." J Davaine§ stated that 1 in 15,000 killed anthrax. 

* B. M. A. Reports, 1888. t Archie, f. exp. Pathol., vol. iv., p. 80. 

X Mittheil. a. d. k. Oesund., 1881, p. 234. 
§ Bull, de I' Acad, de Med., July, 1880. 


Vallin says that 1 in 2,500 is effective under most unfavourable cir- 
cumstances.* Billroth, Haberkorn, iind Kuhn likewise recommend it. 
Therefore, though it cannot be employed for preserving food on account 
of its poisonous nature, it has been used for injecting corpses and by 
most governments for local disinfection. Dr. Collingridge, in a private 
communication informs me that for ships' crew's spaces, rooms, &c., 
after fumigation by sulphur either by the ordinary process of com- 
bustion or by the liquid sulphurous acid, he washes with a solution of 
mercuric chloride of 1 in 2,000. Vessels entering the Mississippi 
suspected of contamination are sprayed over all surfaces excepting the 
cargo with a solution of 1 in 1,000.1 The hold is then disinfected 
with sulphur. Since mercuric chloride is non-volatile at ordinary 
temperatures, it cannot affect the air throughout the spaces, hence it 
only acts as a strictly local disinfectant. 

But Klein has very much reduced the above too favourable estimates 
of the power of this salt. He considers it an efficient germicide, but 
maintains that Koch and others have overrated it. In 1885 Blyth 
conducted a series of experiments in which he treated anthrax spores 
with 1 in 1,000 solution of mercuric chloride, as others had done, when 
he noticed that the bacteria were apparently killed and the spores 
ceased to develop ; but on then inoculating guinea-pigs with the 
appai'ently sterilised infusion, anthrax rapidly appeared, the animals 
died, and the blood was swarming with Bacillus antliracis. He con- 
cludes that a solution of 1 in 1,000, although it kills the non-spore- 
bearing organisms, only stupefies and does not destroy the sjjores of 
Bacillus anthracis.X Dr. Woodhead§ explains Klein's x'esult as due to 
the precipitation of the mercuric chloride by the albumen present, 
" which gave a coating or pellicle of albuminate of mercury round the 
spores, protecting them from further action until they were introduced 
into the blood of the animals, when the excess of albumen re-dissolved 
the pellicle and set the organism free to flourish in its new surround- 

Grace Calvert also pointed out, many years ago, that mercuric 
chloride "destroys vibrios but not fungi;" and H. Schulz|| has shown 
that a solution of 1 in 500,000 increases the activity of Saccharomyces 

Koch has repeated his experiments and somewhat modified his 
earlier conclusions. He still affirms that mercuric salts, especially the 
chloride, are most valuable. " For a ship's bilge, where a 5 per cent. 

♦ Traite, p. 117. t Pharm. Journ., 1887, p. 144. 

t Micro-organisms of Disease, 1886, p. 261. 

§ Proc. Boy. Soc. of Edinburgh, vol. xv. , p. 246. 

II PJluger's Archiv,, voL xlii., p. 517. 



solution of carbolic acid must be left for forty-eight hours, a 1 in 1,000 
mercuric chloride solution only required a few minutes." He admits 
that " there is on the other hand reason for doubting the efficacy of 
this salt, for though anthrax spores subjected to a 1 in 20,000 solution 
for ten minutes and then washed in alcohol gave no growth in nutrient 
gelatin, silk threads infected with the spores and then exposed for ten 
minutes to a 1 in 20,000 or even 1 in 10,000 solution proved fatal to 
mice." * 

Herroun considers that the value of this substance as an antiseptic 
has been very much overrated, as he has cultivated ordinary septic 
bacteria in albuminous filtrates containing 1 in 20,000 of mercuric 
chloride. " It is precipitated by albumens if used in greater strength^ 
and is readily converted by the sulphur of all bodies into insoluble 
mercuric sulphide which is practically inert." It may be remarked 
also that mercuric chloride is precipitated by any alkaline solution such 
as ammonia, &c. Laplace in a series of experiments found that 5 c.c, 
of blood serum was sufficient to precipitate the mercury from 5 c.c. of 
a solution of the strength of 1 in 1,000, but that by adding hydrochloric 
acid in the proportion of 5 in 1,000 the formation of the precipitate is 
prevented. Similar results are obtained when tartaric is substituted 
for hydrochloric acid.f When about 10 parts of sodium chloride are 
added to 1 of mercuric chloride, the coagulation of the albumen is also 

It may be concluded that Klein's results are confirmed, and that 
Woodhead's explanation is at any rate part of the truth. It follows 
that the minimum must be raised to 1 in 500, and that the solution 
should be aciditied, preferalily with about ^ per cent, of hydrochloric 
acid, which adds much to the antiseptic power. If, as already men- 
tioned, permanganate is used with it, or some colouring matter like 
indigo or aniline blue be added, the advantage of the warning colour 
is obtained. In the United States mercuric chloride is held in great 
esteem. Dr. Mead Bolton J gives the following table of the minimum 
strength required of various disinfectants : — 


Chloride of Lime. 

Mercuric Chloride. 

Carbolic Acid. 

Typhoid bacillus, 
Cholera spirilluni, 
Anthrax spores, 

Staphylococcus aureus, 
, , citreun, 
„ albus. 

1 in 2,000 
1 in 2,000 
1 in 100 

1 in 200 
1 in 50 
1 in 200 

1 in 10,000 
1 in 10,000 
1 in 1,000 (?) 

1 in 100 
1 in 100 
1 in 50(?) 
1 in 100 
1 in 1(0 
1 in 100 

• Crookshank's Bacteriology, 1887, p. 150. t Brit. Med. Journ., 1888, p. 148. 
+ Report ofComm. on Disinfectants of Amer. P. If. Aanoc., 1889, p. 236. 


The American Public Health Association recommend a solution of 
1 in 500 of mercuric chloride to be used for spore-coutaining infected 
material, and 1 in 2,000 for that which does not contain spores, as 
compared with 5 per cent, carbolic or 10 per cent, zinc chloride. 
Hands are washed in a 1 in 1,000 solution. The dead are wrapped in 
sheets saturated with 1 in 500 ; walls are washed with 1 in 1,000, and 
ships sprayed liberally with the same strength. 

The French authorities adojit a solution containing 1 gramme of 
mercuric chloride and 3 of tartaric acid in 500 of distilled water for 
■disinfecting rooms (Laplace's formula). 

In Paris, spraying rooms after infectious disease with a 1 in 1,000 
solution of mercuric chloride by means of a " pulverisateur " has found 
much favour during the last few years, and the results obtained are 
said to be highly satisfactory. No bad effects have followed this 
practice in Paris, although 35,000 houses were disinfected in this way 
in 1893, and considerably more in 1894. In Berlin this practice is 
not recommended, and in India cases of salivation have been attributed 
to the use of a mercuric chloride solution as a disinfectant wash for 
floor boards. 

The Italian Minister of the Intei-ior has recently called the attention 
of the railway companies to a clause of the sanitary laws which is as 
follows: — "The whole inside of the carriage is to be repeatedly 
brushed over with a 2 per mille solution of sublimate. Cattle trucks 
are to be thoroughly washed with a solution of carbolic acid, or an 
equivalent disinfectant, and with corrosive sublimate when animals 
suffering from a contagious disease have been in the trucks." It is to 
be noted that mercuric chloride solution, especially if acidified, would 
rapidly injure the cushions or hangings. Dr. Thorne, the Medical 
■Officer of the British Local Government Board, believes corrosive 
sublimate, so far as cholera is concerned, to be its most potent germ- 
icide. The official circular issued by Sir G. Buchanan in April, 
1888, was confirmed by the Board in 1892. The following method 
is recommended : — " Por the purposes of the sick room, such as 
reception of soiled handkerchiefs, sheets, and the like, as well as for 
the swabbing of floors, a valuable disinfectant solution may be made 
with perchloride of mercury. It is well to have this solution slightly 
acid, coloured also in such a way that it shall not readily be confused 
with drinks or medicines; and proper caution should be given to avoid 
accidents in its use. Sanitary authorities will find it advantageous to 
have such a solution prepared under the direct instructions of the 
medical officer of health, and supplied at a uniform strength at the 
infected house by the order of that officer. A solution fitted for the 
desired purposes may be made with half an ounce of corrosive sub- 


limate, 1 fluid ounce hydrochloric acid, and 5 grains of commercial 
aniline blue, in 3 gallons (a bucketful) of Common water. It ought 
not to cost more than threepence the bucketful, and should be further 
diluted. The use of non-metallic vessels (wooden or earthenware) 
should be enjoined, and articles that have been soaked in it should be 
set to soak in common water for some hours before they go to the 
wash." The strength of the above solution is 1 in 960 ; it should be 

1 ounce of mercuric chloride, or about 1 in 500. 

Dr. C. T. Williams, of Brompton Hospital, states that mercuric 
•chloride (as well as arsenic, boric, and strong acids) do not interfere 
with the tubercle bacillus, but rather promote its growth. Dr. 
Whitelegge, on the other hand,* asserts that sulphate of iron and 
chloride of zinc are useless, and that the best known disinfectant 
is mercuric chloride. Ratinioff t gives a table of comparative values 
of disinfectants, and cites experiments showing that amounts of mer- 
curic chloride from 1 in 13,300 to 1 in 800,000 killed, in his experi- 
ments, various infective organisms, which results are at variance with 
those of other observers. Dr. A. Ivert in 1889 treated forty-five cases 
of Asiatic cholera in Tonquin with mercuric chloride internally, in 
doses of '02 to '04 gramme per twenty-four hours. The death-rate 
among these was 20 per cent., whereas the general death-rate was not 
less than 66 per cent. He also tried it as a prophylactic agent, and in 
no case did any signs of cholera develop. J F. A. Coward § gave mer- 
curic chloride (and tinct. ferr. perchlor.) internally in sixty cases of 
diphtheria. In some cases he also sprayed the throat with a solu- 
tion of mercuric chloride, glycerine, and potassic chlorate. All were 
successful, even without the spray. 

Solutions of the strength of 1 in 1,000 to 1 in 10,000 have been 
for many years used as antiseptic di-essings by surgeons and by 
dentists. If strong, the mercury will be absorbed, causing salivation, 
and local irritation may also be produced. The formation of an in- 
soluble mercuric "albuminate" with the serum exuding from a wound 
is apt to throw the mercury out of action. In Laplace's solution this 
is prevented by adding tartaric acid to the liquid (see p. 138); but 
Drs. Lubbert and Schneider found that the acid caused irritation to 
wounds, therefore they use a solution containing mercuric chloride 

2 parts, sodium chloride 100, distilled water 600, glycerine 100, 
rectified spirits 200, to prevent the albuminate precipitating. || Dr. 
Wilson's solution is 1 of mercuric chloride, 1 of ammonium chloride, 
and 1,000 of water.H The "St. Bede Disinfectant," made at New- 

* Lancet, 1887, p. 76. t Jiied. Centralblatt, vol. xiv., p. 360. 

X Comptea Rendus, vol. cvii., p. 695. § Brit. Med. Journ., 1891. 
II Chem. and Drug., 1893. IT Pharin. Journ., 1891, p. 960. 


castle-on-Tyne, consists chiefly of sojlium sulphate, mercuric chloride, 
and a little sulphuric acid, formed into blocks with indigo, eucalyptus, 
and thymol.* 

M. Balme has invented an antiseptic paper in the shape of perfor- 
ated sheets like postage stamps, made into a book. A white unsized 
paper is employed, as it is found not to reduce the mercury and lose 
strength as gauze does. In the manufacture, on to each sheet is 
dropped from a pipette a known quantity of a standard sublimate 
.solution. When dry they each contain an exactly known amount of 
the agent, and only require to be moistened and applied to the wound. t 

" Sublimate gauze," as used in the German Army, contains about 
1 iu 200 or 300 of HgCl2, and is coloured pink by magenta to dis- 
tinguish it. " Sal alerabroth '' (ammonio-mercuric chloride) gauze is 
also made coloured with aniline blue. 

It has been mentioned that it is better to employ distilled water 
for making up sublimate solutions, as the carbonate of lime in ordinary 
water causes a precipitate. As distilled water may sometimes, as in 
war, be unattainable, the difficulty can be avoided by adding an acid, 
as in the English and French prescriptions. As an alternative an 
alkaline chloride may be added; ordinary salt is generally chosen 
for this purpose. Victor Meyer considers the addition of salt and 
the use of distilled Avater to be unnecessary, since he found that a 1 
per 1,000 solution of mercuric chloride made even with a bad pond 
water kept well in the dark for two months.! 

C. J. Bond§ recommends a pellet containing 4| grains of mercuric 
chloride and 4J of sodium chloride which can be dissolved in a pint of 
water in about three minutes, forming a solution of 1 in 2,000. Solu- 
tions made with salt do not turn milky with hard water like those 
with ammonium chloride. 

Vignonjl points out that as a definite strength is of the utmost im- 
portance, the permanence of the liquids must be secured. He noticed 
that a 1 per mille solution of mercuric chloride in pure distilled water 
becomes slightly turbid in from twenty-four hours to two or three 
days, and gradually gives a white precipitate. He obtained the 
following results : — 

Mercuric chloride per litre 
(in solution). 

Original solution, . I'OOgranirae. 

Open to air for 7 days (volume reduced by 
evaporation from 500 to 385 c.c, and, 

therefore, solutions became stronger), . 0'57 ,, 

In a closed riask for 7 days, .... 097 ,, 

In a closed flask for 220 days 0*67 ,. 

* Lancet, vol. ii., 1889, p. 701. t C/tem. and Drug., 1889, p. 119. 

::: Ber., vol. xx., p. 2,970 (1888). § Chtm. and Drug., Aug. 9, 1890. 

II C. i?., 1893, Dec. 4. 


Colouring matters diminish the loss, indigo being better than 
fuchsine (because the former is acid), but still there is a loss under 
the best circumstances from 1 -00 to 0-98 in 7, and to 080 in 220 days. 
The alkaline chlorides generally help the keeping power. Solutions 
with 10 grammes of sodium, ammonium, or potassium chloride to 1 
gramme of mercuric chloride, keep practically unaltered for a very 
long time. 1 per 1,000 of hydrochloric acid acts in the same way, 
and would be as useful in those cases in which its irritant effect was 
not objectionable. 

It is evident that the weakening is due to dissociation, a basic 
chloride precipitating and an acid remaining in solution. Exposure 
and heating cause the hydrochloric acid to be volatilised. The double 
salts are more stable, therefore 1 per cent, of salt, or 10 per cent, of 
hydrochloric acid, should be added in making up the solution. The 
sublimate dissolves more readily when it is finely powdered and well 
agitated with the liquid, as it is sparingly soluble and rapidly settles. 
Mercury Albuminate, the white flocculent precipitate given on mixing 
mercuric chloride with dilute albumen, is non-putrescent, insoluble in 
water, but soluble (while moist) in sodium chloride, and in excess of 
albumen, thei'efore in blood, serum, «fec. Gauze impregnated with it 
is a slow, but mild and effective mercurial antiseptic* 

Mercuric Iodide, Hglo, made by precipitating a mercuric salt by 
potassium iodide, is scarlet, insoluble in water, but easily soluble in 
excess of potassium iodide, to form a double salt, potassio-mercuric 
iodide. This has lately come into use as a disinfectant, being said to 
have "double the bactericidal power of corrosive sublimate, while 
it is less poisonous." It was first suggested by Dr. Bernardy, of 
Philadelphia,! and has been patented in France and England by 
Collin and Benoist.:J: They use 1 part of mercuric iodide to 1 part of 
potassium iodide. "5 to 15*5 grains are added to a litre of the animal 
or vegetable liquid to be preserved. Solids are treated with a solution 
of 15'5 grains per litre (1 in 1,000) for twelve to twenty-four hours, 
when the germs are all destroyed." They also mention mixing it 
with eucalyptus and other substances. It is asserted that a solution 
of this compound of 1 in 4,000 is equivalent to 1 in 2,000 of mercuric 
chloride. " For washing floors a solution of 1 in 4,000 should be 
employed, for disinfecting the hands 1 in 2,000, and for instruments 
1 in 2 to 3,000.§ Steel instruments would be attacked unless im- 
mediately rinsed. 

The solid compound is manufactured under the name of " Iodic 

* Schneider, Pharm. Centralhlatt, 1888, p. 141. 

t BrU. Med. Journ., 1887, p. 789. t Patents, Nos. 15,766 and 16.935, 1887. 

§ BrU. Med. Journ., 1887, p. 789. 


Hydrarg.," and is stated to dissolve without decomposition in an equal 
weight of water. It is recommended by Waschejewsck for ophthalmia 
in a strength of 1 in 5,000. " It does not precipitate albumen 
nor cause irritation, and can even be given internally in doses of a 
quarter grain." It has also been compressed into tablets of definite 
weight. One soloid of "Hydrarg. Perchlor." in a pint of water gives 
a solution of 1 in 1,000. Two of "Iodic Hydrarg." in the same 
quantity gives a strength of 1 in 4,000. 

P. K. Bolshesolsky* strongly recommends a 1 in 10,000 solution of 
this salt as an antiseptic in obstetrical and surgical practice. 

Thomson proposes as an antiseptic, 1 to 3 of mercuric iodide and 
1 to 3 of potassium iodide to 100 of soap. The solution for use contains 
1 of mercuric iodide in 4,000 of water. Dr. Woodhead has experimented 
on it with favoui'able results.! 

Mercuric Cyanide, Hg(0N)2, is sparingly soluble in water, slightly 
acid, and inodorous. The basic or oxy-cyanide is similar, but slightly 
alkaline. Both are antiseptic and very poisonous. Solutions of the 
latter, 1 in 15,000 strength, do not seriously injure instruments, only 
slightly precipitate albumen, and are tolerated by wounds and by the 
mucous membrane. Chibret:}: found when he added it to peptonised 
broth that it had six times the antiseptic power of the chloride, although 
it does not act so powerfully on Micrococcus aureus. It has also been 
found of service in cases of diphtheria. 

Stellden§ reports on 1,400 cases of diphtheria treated with this 
remedy, when only 5 per cent, of deaths occurred, as compared with 
the ordinary 92 per cent, in that district at the time. (Honey, 450 ; 
tinct. aconite, 30 ; Hg(CN)2, 0-3 grain ; also a gargle of 1 Hg(CN)2 in 
10,000 of Aq-menth. pip.). Frequent doses and applications were said 
to suppress the bacillus. 

Zinc Mercuric Cyanide. — Sir Joseph Lister introduced this compound 
in 1889. To a solution of potassio-mercuric cyanide a zinc salt is 
added ; the bulky white precipitate is washed with water till the 
washings are almost free from mercury, then drained, triturated with 
starch, ground with potassium sulphate to aid the pulverisation, and 
carefully dried. To fix it on gauze, 3 to 5 per cent, of it is suspended 
in a 1 in 4,000 solution of mercuric chloride, and the gauze dipped 
with agitation. The powder keeps when dry, but the gauze must be 
prepared when required, and used moist. 

B. Dotty cast some doubts on the definiteness of this compound, 

* Proc. Arkhangelsk Med. Soc, 1S94, vol. ii., p. 191. 

t Brit. Medical Association, Edinburgh Meeting, 1888. 

t Compt. Rend., vol. cvii., p. 119. § Merck's Bull., vol. i., pp. 28-40. 

II Lancet, vol. ii., 1889, p. 1133. 


questioning the presence of mercury in any quantity. Dunstan* 
proved that the original precipitate, which he prepared by a variety 
of methods, was a true double salt of the formula Zn^Hg(CN)j^ or 
HgCNo, 4Zn(CN),, but that it was decomposed in the washing, 
the soluble Hg(CN)2 being removed, and the insoluble Zn(CN)2 
remaining, so that the result was a mixture of variable composition 
consisting mainly of zinc cyanide, with, in different samples, 6, 8-5, 
10, and 18 per cent, of Hg(CN)o — that is, about a ^ to ^ of what 
it should be. Long washing or hot washing removes all the mercury. 

However useful in practice this preparation may prove to be, 
the variation in its composition militates against uniform results. 
Dunstan tried to prepare it in alcohol and other ways, but without- 

Mercuric Chloro-amide, HgNHgOl, is the soluble white powder 
well known as "white precipitate." It is much used for killing 
Pediculi, and is a mild intestinal antiseptic. 

The following organic mercurial compounds are all antiseptic and 
have varying disinfectant powers. All are poisonous. They are- 
occasionally used in emulsified lotions or injections, or in ointments- 
and gauze, against syphilis : — 

Carbolate, (CgH50)oHg (Szadek), Sulphocarbolate, and Benzoate- 
{StuTcowenkow) are white powders, almost insoluble in water. 

Salicylate {Silva-Araujo and Szadek) in pills, -^-^ to | grain, and as- 
an injection in 0*4 per thousand solution for gonorrhoea and syphilis, 
has perhaps been more widely used than any other of the newer 
compounds of mercury. 

Thymolate (CjoHj3 0)Hg.HgN03, Thymolacetate, and Thymosul- 
phate, yV to \ grain in pills, were recommended by Kobert for 

Tannate, greenish-brown insoluble scales ; 1 to 2 grains have been 
recommended as an antisyphilitic by Lustgai-ten. 

Imidosuccinate, (C2H4(C02)2N)2Hg, is soluble in 25 parts of water. 
4 grain is used hypodermically in syphilis (Fbw Mering and VoUert^ 

Naptholate and Naptholacetate are condemned by laddosohn and 
Zeissing as producing pain. 

Peptonate and " Glutino-peptone sublimate," made by acting on 
gelatine with hydrochloric acid and adding 25 per cent, of mercuric 
chloride, are met with in 1 per cent, solution for injections, and are 
said to be almost painless and to be rapid and efficient (Dr. Hufer), 
The doses are about equal to \ grain of mercuric chloride. 

Any surfaces washed with a mercury salt will soon be blackened 
* Chcm. Soc. Jcnrn., 1892, p. C66. 


■vrith sulphuretted hydrogen. Organic matter is liable to reduce and 
throw the mercury out of action. The mercuric solutions are com- 
patible with i)ero.\ide of hydrogen, acids, permanganate, zinc and 
copper salts, glycerine, phenol, and most aromatic compounds, but 
not with borates, sulphates, phosphates, carbonates, or alkalies, which 
precipitate them. 


Tin. — stannous Chloride (protochloride of tin), SnClg, has been sug- 
gested as a disinfectant.* It is comparatively safe, and does not 
corrode lead pipes. A solution containing 1 per cent, kills spores 
after an exposure of two hours. When kept for use it should be 
mixed with an equal quantity of ammonium chloride, which prevents 
the formation of the insoluble oxychloride of tin. 

It is difficult to see any advantage in its introduction, as its bacteri- 
cidal powers are feeble, and chiefly due to its hydrochloric acid. It would 
absorb ammonia and sulphuretted hydrogen, like many other agents. 

Bismuth. — Gayon and Dupetit f were the first to point out that 
salts of bismuth, even in small quantities, completely prevented the 
secondary fermentations which take place in worts, but they have not 
been used to any large extent. 

Bismuth subgallate, C-H-O^-Bi, formed by the action of bismuth 
nitrate on gallic acid, is soluble in water, alcohol, and ether, has lately 
been introduced under the name of " Dermatol." F. Rohrer | says 
of it, "This new disinfectant in the different forms of purulent in- 
flammation of the outer and middle ear, also in affections of the nose, 
has lately claimed to be a great success. A bacteriological test, in 
which dermatol mixed with broth or gelatine was infected with 
anthrax, has revealed, however, that it is not a germicide, and does 
not even retard the growth. In fact, the bacillus actually changes the 
dermatol, which becomes yellow, and finally black. The same dis- 
coloration occurs in the ear." So that it simply acts as an astringent. 

Colosanti and Dutto, on the other hand, report favourably on its use 
.as an internal disinfectant. 

The salts of other metals have not been used to any large extent. 

iVIiquel classes Silver Nitrate as equal to mercuric chloride. 

Osmic Acid is a very powerful bactericide, as mentioned by Klein 
•and supported by Koch. Koch says that Silver and Gold compounds 
are all inhibitory on tubercle, especially Gold Cyanide, Au(CN)3, dis- 
solved in potassium cyanide ; 1 part Au(CN)3 in 2,000,000 parts of 
solvent checking the growth of tubercle bacillus. 

• Year-Book of Pharmacy, 1887. t Comp. Rend., vol. ciii., p. 883. 

i Centr.f. Bacteriol, 1S92, vol. xii., p. 625. 


With reference to compounds generally, in view of the search for 
new disinfectants, it may be mentioned that — 

1. As free acids, even the weakest, such as acetic and carbonic, 
retard, as a rule, the growth of bacteria, which usually require a 
slightly alkaline medium, the acid salts and those of the metals which 
have an acid reaction retard putrefaction by virtue of their acid con- 
stituent, and independently of the nature of the metal. 

2. Some metallic salts precipitate albumen — e.g., those of mercury, 
copper, and most of the heavy metals. Such, by coagulating protoplasm, 
must kill the organisms, if they can penetrate deep enough. With 
these salts, disinfection is, therefore, a condition of quantity and time. 

3. These metallic salts, and some other substances, such as lime, 
alumina, phosphates, and charcoal, may starve bacteria by withdraw- 
ing, or rendering insoluble, their food. 

4. The borates, aroniatic substances generally, and a few other com- 
pounds exert a direct toxic influence on organisms which, as far as 
known, is physiological and not chemical. Given sufficient quantity 
and time, they may actually kill the bacteria and so act as real dis- 
infectants, but they usually only retard the growth, and therefore are 
chiefly used as antiseptics. It is possible that some of them may 
form loose compouilds with protoplasm which interfere with its vital 

5. Reducing agents, such as sulphites and ferrous salts, withdraw 
oxygen, which element is necessary for the growth of most organisms. 

6. Oxidising agents, like ozone, peroxide of hydrogen, the halogens, 
and permanganate, act on bacteria by destroying their food, poisoning 
them, and finally completely destroying them. These are the only 
perfect disinfectants, yielding the ideal condition of sterility, nothing 
to grow, and nothing to feed on. It remains solely to find the 
minimum required, and then to use a little more for safety. All 
other disinfection must be unsatisfactory, and only means suspension 
for a time. 

7. A few easily reducible metallic salts are fed oh by the organisms, 
which assimilate one of the elements, to be deposited in their tissues 
as coloured granules distinctly visible under the microscope. Silver, 
gold, and some iodine compounds are examples. After a time this 
deposition chokes, and finally kills them. Probably this accounts for 
the fact so often observed, that very minute percentages of many 
poisons actually promote the growth of organisms, which larger 
amounts destroy. Ordinary therapeutics furnish many parallel in- 
stances.* Richet remarks f that, although very small quantities of 

• Note Crace-Cal vert's observation under Mercury, p. 136 ; Dr. Williams, ibid., 
p. 139. t Comptes Rendus, 1892, p. 1494. 



certain metallic salts retard or wholly prevent the development of the 
lactic ferment in milk, still smaller^ quantities even act as accelerators 
of the fermentative action. 

This explains the absolute necessity of working quantitatively in 
disinfection, and also many of the discrepancies and misstatements 
which exist in the literature of the subject. 

Richet also observes * that the ferment appeared indifferent to salts 
of copper and mercury in quantities inferior to "00025 gramme per 
litre; in doses of '0005 gramme per litre these salts possessed an 
accelerative action, and in quantities of 0-001 per litre their antiseptic- 
properties first became evident. The toxic action of the metallic 
poison does not appear to affect the chemical activity of the ferment^ 
but rather its powers of multiplication. The biological relations as- 
regards the toxicity of metals do not follow chemical laws, as certain 
metals which are chemically very similar have a very different toxicity, 
and it is especially noteworthy that the rarer metals, to which the 
ferment is pi'obably not so well accustomed, appear more toxic than 
the common metals. The prohibitive dose of zinc is 1 gramme, whilst 
0"15 gramme of cadmium sulphate completely prevents fermentation. 
Ferric and manganese salts are also less toxic than cobalt and nickel 

While calcium salts are constituents of food, barium, chemically the 
next metal, gives compounds that are poisonous. Among the rarer 
metals may still be found a stronger antiseptic than any yet examined. 
It would appear that in a series of similar metals the higher the atomic 
weight the more toxic the salts. In the case of the non-metals the 
reverse may be the case, but at present there is want of data for 
ascertaining how far the periodic law of the elements bears on their 
antiseptic and disinfectant action. 

* Loc. cit. 



Coal Tau and its Products : General Account— Tar Water. Hydrocarbons 
(Neutral Tar Oils) : Benzene — Toluene — Naphthalene — Anthracene — Naph- 
thalene Urinal Cakes — "Lauraline." Petroleum. Phenols. Phenol or 
Carbolic Acid : " Properties " — Variation in the Commercial Strength — The 
" Victoria Carbolic Acid Powder"— Carbolic Fumigation — Antiseptic Power 
of Phenol — Not a Disinfectant — Uses and Dangers— Objections to the employ- 
ment of Phenol — Prescriptions in Different Countries. Carbolic Powders : 
M'Dougall's — Calvert's — Mayor's — Phenolith — Other Patents. Surgical 
Preparations : Carbolised Oil — Gauze— Carbolic Wool — Danger of Phenol 
in Surgery — Carbolic Soaps — Tooth Powders — Various Preparations — The 
cost of Phenol. Halogen Compounds of Phenol : Tribromophenol — lodo- 
phenols. Sulphonic Derivatives: " Sulphocarbolates " — Sozo-iodol — Aseptol 
— Sozol— Benzene-sulphonic Acid — Phenyl substituted Patty Acids. Cresol 
AND ITS Higher Homologues : Table of the Phenol Series — Sources — 
Creosote Oil— Ufees of Creosote Antiseptic Powder — "Bacillite " — Lysol — Ex- 
periments on its Efficiency — Pixol — Pixene — Question of Solubility — Tricresol 
— Jeyes' Disinfectant and Creolin — Creolin Baths — Smith's Carbolated 
Fluid— Artmann's Creolin — Strathclyde Disinfectant — Essets' Fluid. Saprol : 
Its Peculiar Properties — Allen's Fluid — Production of Ozone. Izal: Euro- 
phene — Resorcinol — Pyrocatechol — Pyrogallol. Wood-Tar Derivatives i 
Products of Destructive Distillation of Wood — Stockholm Tar — Retinol — 
Resol — Fatal to Plants. Wood Creosote : Uses and Antiseptic Power. 
Guaiacol : Medicinal Uses — Guaiacol Carboxylate — Creosol — Kresyline — 
Little's Soluble Phenyle. Naphthalene and Naphtiiol : Naphthalene 
— Naphthalene-Sulphonic Acids — Naphthols — Beta-naphthol — Its Value in 
Internal Antisepsis — Betol " Microcidine " — Alumnol— Hydronaphthol — Its. 
Use in Gauze — Oxynaphthoic Acid, 


It has long been known that the varieties of tar have antiseptic and 
preservative properties ; hence the use of coal tar for coating wood, 
and of wood tar for ropes and sacking. Coal tar consists for the most 
part of a mixture of " aromatic " compounds derived from the hydro- 
carbon benzene, OgHg. They are more or less volatile ; many have 
offensive odours, and act as narcotic poisons. This poisonous action 
may render them disinfectant when used in sufficiently large quantities. 
Some coagulate albumen, and are caustic, like phenol. A few are 
soluble in water, and these are the most powerful physiologically. As 
far back as 1753 Bishop Berkeley extolled the virtues of tar water for 


nearly every ailment ; but its use is now replaced by more definite 

By treatment with acid and alkaline solutions in succession, the 
tars are separated into three groups of bodies : — 

I. Hydrocarbons, such as benzene, toluene, xylene, naphthalene, 
anthracene, &c. These are neutral bodies, insoluble in water, alkalies, 
and acids; Most of them, however, can be dissolved, or at least 
emulsified, by heating with a strong solution of ordinary or resin soap, 
with or without the addition of alcohol or wood spirit. The dark- 
brown clear syrup turns white and milky with water, the hydrocarbons 
being precipitated in minute oily globules, which slowly rise as a scum 
to the surface, leaving a strongly alkaline solution in the soaps. All 
these mixtures smell of tar, and are in different degrees antiseptic, 
but less so than the phenols. They are known in commerce as 
■" neutral tar oils." Specifications for disinfecting powders generally 
demand their absence, and in fact they are looked upon usually as a 
detriment, or even as an adulteration, if present in any quantity in 
disinfectants. The hydrocarbon benzene, CgHg, and its higher homo- 
logues toluene, C-Hg, tie, have no antiseptic value. The dei-ivatives 
of thiophene (a compound usually present in crude benzene), C^H^S, 
have been used for skin diseases.* 

Naphthalene, C^gHg, and anthracene, Cj^Hjq, when pure are white 
crystalline solids of greasy feel and tarry odour, slowly volatile, in- 
soluble in water, and feebly antiseptic. Naphthalene is used as an 
insecticide, and is sometimes employed locally in scabies as a 10 to 20 
per cent, solution in oil. It is to be avoided in cases where large 
surfaces are exposed, but has been used internallyf and as an antiseptic 
for wounds. + Its derivatives will be further considered (p. 177). 
Naphthalene is at present much used as the basis of cakes or blocks 
sold very cheaply as "disinfectants" to hang up over sinks and in 
closets, and to place in the basins of urinals. Some are said to contain 
"camphor and eucalyptus." The urinal blocks certainly prevent the 
urinous smell, partly by masking it and partly by retarding the 
ammoniacal fermentation, but they are of no use as disinfectants. 
There is a recent patent § for naphthalene tablets. 

" Lauraline " contains camphor and carbolic acid with much naph- 
thalene. || 

Petroleum may here be incidentally mentioned, although it consists 
mainly of the paraffin series of hydrocarbons, chiefly liexane, CgHj^. 
It has long been used as an insecticide in horticulture. 

* Repertoire de Pharm., 1892, p. 157. i Amer. Jourv. of Pharm., 1834, p. 645. 
t Squire's Companion, 1890, p. 289. § No. 5,036, 1892. 
li Chem. and Drug., Sept. 3, 1892. 


II. Phenols or so-called "tar acids," carbolic, cresylic, &c. They are 
hydroxy-derivatives of the aromatic hydrocarbons, and combine with 
caustic alkalies to form carbolates, «tc., soluble in water, from which 
acids again liberate the phenol. The series include phenol, cresol, and 
liigher homologues ; the latter are present in the fractions of higher 
boiling point, and form unstable compounds with alkalies which are 
even decomposed by water ; hence their solutions turn milky on 
dilution. They are the subject of a large number of proprietary 
preparations, and will be described further under phenol, cresol, &c. 

III. Basic substances are extracted from coal tar by treatment with 
acids. They include aniline, pyridine, quinoline, ifec. They are mostly 
soluble in water, and are discussed more fully in a later section 
(p. 184). 


Phenol, C^'ilr^(0'H.), is the simplest member of the group of phenols 
or hydroxy-benzene derivatives, and is commercially known as carbolic 
acid. The phenols all contain hydroxyl united to the "aromatic" 
nucleus or benzene ring of carbon atoms, and are more or less anti- 
septic. Most of them coagulate albumen, and are therefore styptic ; 
they are poisonous in different degrees, and thus, if in sufficient quan- 
tity, may be true disinfectants. They are mostly of sparing solubility 
in water, which militates against their general use; they easily dissolve 
in alkalies and alkaline earths, forming substitution compounds usually 
called carbolates. These compounds are alkaline, odorous, and some- 
what caustic ; acids, even carbonic, render their solutions turbid, 
separating the phenols as an oily layer if the solution is moderately 
concentrated. Such substances, made with lime or magnesia, constitute 
a number of the "disinfecting powders," which slowly give off the 
phenols on exposure to air, leaving behind the inert carbonates of 
lime and magnesia. The earthy bases then only act as a vehicle, and 
any undue excess of them must be considered as an adulteration. 
The pure compounds are not used, as they are deliquescent, caustic, 
and too rapidly soluble. The powders are usually valued and sold as 
containing a stated percentage of the phenol, «kc. Many so-called 
disinfecting powders now in the market are supposed to contain 15 per 
cent, of phenol, when in reality they possess only a trace. "A 15 per 
cent, carbolic acid disinfectant powder, free from tar oils and sulphur- 
etted hydrogen " {i.e., not made from gas-lime), is a common form of 
speciBcation for this class of disinfectant. 

A striking example of the absolute necessity for carefully examining 
all such powders before use is furnished by the recent exposure of the 
" Victoria Carbolic Disinfectant Powder." Dr. Barwise found in an 


epidemic of typhoid at South Wingfield in 1892 that " excreta well 
mixed with the powder and buried " polluted the drainage, so that the 
infection was carried to a large number of people lower down the hill. 
Although the powder was stated to contain 15 per cent, of carbolic 
acid, an analysis showed that it had barely any odour of carbolic acid 
and only the merest trace of tar oil, and there was no weighable quan- 
tity of carbolic acid. Moreover, even the best powders deteriorate on 
exposure to air, and may become inert. Phenol itself is prepared from 
tar distillates, and in the crude state is a dark oily liquid containing 
also the higher homologues, cresol, xylol, cumol, and cymol, besides 
neutral tar oils of less disinfecting power. "Synthetic" carbolic acid 
(made from benzene), and free from cresol, (kc, has been sold, but its 
price is somewhat prohibitive. Pure phenol forms colourless crystals, 
turning red in the light. It melts at 41° C. and boils at 181-5° C, 
and therefore is not easily volatile. It can be volatilised more rapidly 
by melting and then dropping on to a heated shovel — not too hot, or 
it is liable to catch fire {Calvert). The vapour is apt to cause severe 
headache, giddiness, and nausea. A small quantity of water liquefies 
the crystals, forming a hydrate, which, however, when added to more 
water, only dissolves to the extent of 1 in 15, the rest generally at first 
floating as an oily layer, although it is slightly heavier than water 
(specific gravity, 1*065). Hence it must be made into a solution for 
use by mixing with excess of water and agitating until dissolved. 

It is certainly antiseptic ; but as to its disinfecting power, opinions 
are very diverse. M'Dougall and Calvert extolled it above other 
disinfectants ; but the latter observer, though he states that 1 in 200 
prevented the putrefaction of beef juice for six days, yet acknowledges 
that when added in that proportion to already putrid beef juice or egg 
albumen, it had no efiect on the organisms present. The vapour also 
produced no effect during twenty-four hours on vaccine lymph. 

Miquel asserts that the vapour of phenol " after fifteen or twenty 
days of action at 20° C. is absolutely incapable of destroying the vitality 
of bacteria," and that 3-2 grammes of phenol is required to prevent 
growth in a litre of beef tea.* 

Pasteur and Lister have strongly advocated its use in surgery where 
antiseptic action is mainly aimed at. Phenol was extensively tried by 
Orookes under the sanction of the Cattle Plague Commission. His 
report estimated its value in destroying the infectious matter as very 
high (1867). 

Koch remarks! that "carbolic acid also kills if of considerable 
strength and acting for a long period." He also observed that solu- 

* Les Organismes, 1883, p. 290. 

t Mitiheil. a. d. K. Gesund., 1881, vol i., p. 234. 


tions of carbolic acid in oil do not possess the same disinfecting power 
as those in water. This is important, in view of the frequent use of 
oarbolised oil in surgery. 

When disinfection is required to be completed in less than twenty- 
four hours, which is generally the case, Wolffhiigel and Von Knorre 
find carbolic acid useless.* 

In Koch's later experiments, silk threads with anthrax spores were 
placed in cai'bolic solution of various strengths. A 5 per cent, solution 
killed the spores in two days, whilst sporeless bacteria, as those from 
fresh blood, were killed by 1 per cent, solution, but not by ^ per cent, 
solution, as proved by inoculation. " For safety the strength should 
be 5 per cent, or even more to kill in twenty-four hours." "As an 
antiseptic, phenol solution 1 in 850 entirely prevented the development 
of anthrax spores, 1 in 1,250 caused marked hindrance. Other bac- 
teria are less affected. The vapour at ordinary temperatures, even 
when allowed to act for six weeks, had not the slightest effect on 
spores, but at 55° C. many were destroyed in half an hour. After 
three hours there was very little germinating powei', after five or six 
all were killed. Other disinfectants act similarly at high tempera- 
tures." t (See p. 139 for Ratinoff's comparison of phenol with mercuric 
chloride, &c. His effective strength is 1 in 400.) 

Klein observes that phenol (1 in 400 or 500) in nutrient solutions 
has a decided restraining power, but he emphasises the fact that the 
spores are only " stunned," not killed ; for, if removed and inoculated 
into an animal, they recover and rapidly cause death. He continues, 
" as is obvious, according to the nature of the bacillus, the strength of 
the solution, and the time of action, the result varies. For instance, 
mature B. anthracis is killed by 5 per cent, phenol in five minutes, but 
is not injured by 1 per cent, in five minutes." 

Crookshank obtained favourable results on the tubercle bacillus. 
Patients whose lungs were tuberculous have been benefited by inhala- 
tions of carbolic vapour. % 

As to the typhoid bacillus, it is so resistant to phenol that the 
isolation of this organism is effected by growing in a carbolised culture 
which kills other germs, but has no action on it.§ It is grown in 
tubes of gelatine by adding to each 10 c.c. of the nutrient medium, 
4 or 5 drops of 1 in 20 per cent, phenol. Cassedebat at Marseilles 
found that several other organisms offered quite as much resistance to 
phenol as the typhoid bacillus itself || Yet Dr. Cameron recommends 

* Journ. Soc. Chem. Ind., June 29, 1882. 

+ Mittheil. a. d. K. Gesund., Dec. 3, 1881. t Bacteriology, 1887, p. 151. 

§ Chautemesse and Widal, Oaz. Hebdomadaire, 1887, p. 146. 

II Ann. Inst. Pasteur, Oct. 25, 1890. 


a 5 per cent, solution of carbolic acid for the " decomposition " of 
typhoid stools;* and even more recently Dr. Gover, in his report to 
the Director-General of Prisons, asserts that " Carbolic acid is the 
most certain and powerful of the numerous substances \ised as anti- 
septics and disinfectants." 

The value of phenol may be summed up as follows : — 

1. In a strength of 1 in 400 it is a powerful antiseptic, restraining 
ptitrefaction when started, and preventing it for a long time when not 
commenced, but in this respect it is far inferior to mercuric chloride. 

2. To actually kill bacteria it requires the high strength of 1 in 
20, and even this has not a certain action with all organisms, nor 
does it kill the spores of such as anthrax. Therefore it is not a 
satisfactory disinfectant. 

3. It does not absorb sulphuretted hydrogen nor ammonias, hence 
it is not a deodorant. 

4. Its persistent odour is a decided disadvantage, as the smell 
remains even when the quantity is utterly insufficient. 

5. For treatment of sewage it is a failure, even in proportions 
practically impossible. Moreover, it renders the material useless 
for manurial purposes. In Japan, after a cholera outbreak in 1882, 
the Government instituted some experiments to elucidate this point, 
and clearly showed that "a solution of 0*05 gramme of phenol in 
100 c.c. of water weakened the germinating power of the seeds, and 
with a solution of 0*1 per cent, only one-third of the possible seeds 
germinated, and in all cases the acid delayed the process of ger- 

6. In surgery it is of considerable value. Lister has recently 
pointed out that it has a powerful affinity for the epidermis, pene- 
trating deeply into its substance, and mingling with fatty matter 
in any proportion, whereas mercuric chloride required a special 
cleaning of the skin, as it could not penetrate in the slightest degree 
into anything greasy. It is free from the danger of mercurial 
poisoning, but if used too strong it may itself be absorbed and 
cause dangerous symptoms. For aseptism (prevention) as against 
antiseptism (cure) in surgery it has, therefore, a distinct field of 

Carbolic acid is still in high favour with different Governments 
and medical associations. Thus the recent suggestions made by 
the Society of Medical Officers of Health are as follows : — 

1, For the air of sick rooms : sheets are suspended and saturated 
with carbolic solution or chloride of lime. 

2. For matters passed : ferrous sulphate is added. 

* Brit. Med. Journ., 1S90, p. .370. 


3. All utensils should be washed in carbolic solution. 

4. Linen should be treated with the same. 

5. Ambulances and steamers should be cleansed with carbolic 

The solution recommended is a \ pint of carbolic No. 4 (a pure 
liquefied acid containing about 90 per cent, phenol) to a gallon of 

These recommendations are open to the criticism that : — 

1. The prescribed solution which only contains about 2^ per cent, 
to 3 per cent, of phenol is only half the strength specified by Koch 
and others as capable of killing mature germs, and far below that 
required to destroy spores. 

2. The odour from a suspended sheet is liable, as before mentioned, 
to cause headache and nausea, and it is very improbable that such a 
method of application does more than partially disinfect the air, even 
if the carbolic solution is a saturated one. 

The Commissioners of Inland Revenue in 1892, in an investigation 
for the Board of Trade, state in their report, " That nearly every 
liquid disinfectant on the list was found to be inferior to an equal 
weight of the carbolic acid powder." The Committee decided to adopt 
as standards a solution containing SO per cent, of carbolic acid, and a 
])owder containing 20 per cent. This is practically Messrs. Calvert's 
strength for their liquids No. 4 and 5. Their powder is guaranteed 
to contain 15 per cent, of carbolic and cresylic acids. 

In the Clerkenwell Vestry district where carbolic acid is distri- 
buted free to ratepayers, it is bought on the following specifi- 
cation : — 

" (1) 95 per cent, of clear carbolic acid fluid, free from tar oils and 
sulphuretted hydrogen; (2) 15 per cent, carbolic disinfecting powder, 
with same proviso ; (3) 70 per cent, carbolic acid dissolved in caustic 
soda, also free from tar oils and sulphuretted hydrogen." 

In Russia, carbolic acid seems to be the chief, if not the only, dis- 
infectant employed by the officials. In that country the slightly 
active 50 per cent, to 60 per cent, crude acid has been officially pre- 
scribed, whereas the German law properly orders the use of crude 
100 per cent, acid, which consists of the really active phenol unmixed 
with valueless tar oils.* 

The Berlin administration order solutions of two strengths — 
" strong," consisting of 1 part pure phenol to 18 of water ; and 
"weak," 1 to 45 parts.f The same regulation points out that 
fumigation by means of aromatic substances is of no value in dis- 

* Pharm. Zeitung., Aug., 1892. + Polizei Veronlnung, Feb., 18S7. 


The Belgian Government order 2 or 3 per cent, to be mixed with 
excreta, under the same conditions as in this country. 

Caibolic Powders. — In many cases the base of the powder consists 
of slaked lime, but the " carbolate " of lime, which is formed in this 
way, only slowly gives up its phenol. One of the oldest forms is 
''M'Dougall's Disinfecting Powder," prepared by adding crude carbolic 
acid to impure sulphite of lime obtained by passing sulphurous acid 
over ignited limestone. The sulphite of lime in this powder is added 
to absorb sulphuretted and phosphuretted hydrogen. It dissolves 
readily in water, so that there is no danger of choking drains or 
appreciably increasing the quantity of solids in the sewage. For 
fumigating purposes the powder is mixed with water in an ordinary 
zinc pail, preferably a wooden or earthenware receptacle, adding a 
little sulphuric acid. A " sewage carbolic acid " of 25 per cent, 
strength has been advocated for use in conjunction with the powder 
and with lime, in the proportion of 1 gallon of carbolic acid, 10 lbs. of 
disinfecting powder, 10 bushels of lime, and 100 gallons of water. 
This mixture is stated to be sufficient for 50,000 gallons of sewage, 
which is rendered imputrescible, and all smell is removed. If the 
powder contained 15 per cent, carbolic acid, the total amount present 
in the sewage would barely amount to 8 parts per million, and this 
quantity is totally inadequate for sterilisation, 

Allen* gives the following as the composition of a sample of the 
base of M'Dougall's powder after extraction of the carbolic acid : — 

Silica 2-4 

Alumina, 3*4 

Ferric oxide, Traces. 

Lime, 46"5 

Magnesia, . 0*3 

SO2, 7-5 

SO3, 29-2 

CO2 (water and undetermined matter), .... 10"7 


Corfield remarks: " Carbolates of lime and magnesia and sulphites, 
«uch as M'Dougall's powders, merely assist in delaying decomposition, 
but do not prevent it ultimately." 

"Calvert's Carbolic Powder" is guaranteed to contain 15 per cent, 
©f carbolic and cresylic acids. It is prepared by adding crude carbolic 
acid to the residue left from the manufacture of aluminium sulphate 
from shale or kaolin. The following is an analysis of the base after 
extraction of the phenol : — f 

* Commercial Organic Analysis, 1886, vol. xi. t Analyst, 1878. 


Silica 67-4 

Alumina, 28-0 

Ferric oxide Trace. 

Lime, 0*8 

Undetermined, 3 '8 


" Mayor's Disinfecting Powder " has also a silicate base and " con- 
tains 15 per cent, carbolic acid." The advantage claimed is that "the 
action of the acid is entirely free to perform its work of disinfection, 
none of it being absorbed and retained by the base." 

"Phenolith" contains the phenols and cresols of tar with infusorial 
earth (siliceous), sawdust, &c. ; * the patent also includes the use of 
mixtures of phenol and boric acid for preserving meats, hides, (kc. 

Tweedie t patented a mixture of phenol, turpentine, and camphor 
with " any dry vehicle." 

The carbolic powders of commerce are generally coloured pink or 
brown by aurin or ochre. I 

It is now generally admitted that road disinfection by carbolised 
lime is of little value, since the volume of air and earth is too great 
for any real disinfection to be effected in this way. Local authorities, 
however, in many districts generally regard such treatment with 

In surgery the following preparations containing phenol are used : — 

Carbolised Solution, 1 or 2 of phenol in 40 of water ; Carbolised Oil, 
same strength used as a dressing (Koch states that it has much less 
power than the solution); 2 per cent, solution for hypodermic injections 
and as spray for erysipelas ;§ 5 per cent, injection for anthrax.|] 

Carbolised Gauze (Lister). — Phenol, 1; resin, 4; parajfin, 4; melted 
together and the gauze dipped in this mixture. Vaseline is sometimes 
added to give pliancy. Absorbent gauze is made with phenol, glycerine, 
and dilute alcohol, and is stated to be more powerful than the ordinary 
gauze. At the temperature of the body the phenol is slowly given off, 
causing an antiseptic vapour to envelop the wound. 

Carbolic Wool should contain 5 per cent, phenol. Five commercial 
samples analysed were found to contain 1*06, 1'07, 0*69, 0*25, 5 '08 per 
cent, respectively, showing that they were either badly prepared or 
had lost their strength by careless keeping. Carbolic wool, like all 
articles containing volatile medicaments, should be preserved in per- 
fectly air-tight vessels. 

♦ Holtz, Patent No. 5,193, 1878. t Patent No. 17,042, 1888. 

+ Joum. Soc. Chem. Ind., 1889, p. 913. 

§ Brit. Med. Joum., 1888, vol. xi., p. 947. II Ibid., p. 601. 


Danger of Phenol in Surgery. — According to Lowe, the effect of the 
contact of plienol with any large surface of the lower part of the body 
is apt to be fatal, but it has often been applied to the arms with 
impunity. Gosselin made a series of experiments bearing mostly on 
the action of phenol on the living body, as in surgical operations, using 
1 to 5 per cent, solutions in dilute alcohol upon blood circulating 
through a membrane, and found that the circulation of the blood 
through the capillaries was arrested, in direct proportion to the 
strength of the solution. He supposes that the phenol coagulates the 
blood like a caustic, first (?) acting as a germicide, then " as a semi- 
caustic or astringent." 

Carbolic Soaps are made in great variety. They should contain 
about 8 per cent, or more of phenol, but many contain not more than 
1 per cent. Woodhead* and Cameron f have pronounced against their 
use. They are largely used in washing, and contain tar oils, naphtha- 
lene, ttc, with varying amounts of phenol. Their value is more than 
doubtful as disinfectants, though they certainly are potent against 

Carbolic tooth powders are also made. They are antiseptic, but are 
not very pleasant. 

A few other preparations remain to be mentioned. There are a 
large number of patents for mixing " phenoloids," containing more or 
less carbolic acid, with peat fibre, ground blast-furnace slag, cinders, 
sawdust, and other inert absorbents. They present no special advan- 

" Disinfectol " is an oily blackish liquid containing resinous soaps, 
soda, and compounds of phenol dissolved in hydrocarbons introduced 
into commerce by Loewenstein. It mixes readily with water, forming 
an emulsion. Several preparations of this type, tar products dissolved 
in alkalies, will be described under Cresol. 

" Eademann's patent " is pure phenol melted on a water bath, 
cooled quickly and stirred. The small crystals that separate are 
mixed with 10 per cent, of pure boric acid and pressed into cakes. 
He claims that this form is not injurious to the skin. I 

An "Aromatic Carbolic Liquid," much used in Russia, is a tincture 
of phosphorised phenol with musk, oil of wintergreen, &c.§ 

Phenol has been used internally in capsules and solutions to arrest 
fermentation, b\it opinions as to its value are conflicting. Betol has 
been found far preferable for this purpose {q.v.). 

* Brit. Medical Assoc, Edinburgh Meeting, 1888 ; see under Hgl2, p. 142. 
t Sanitary Record, 1890. t Joum. Soc. Chem. Ind., 1889, p. 131. 

§ See Chemist and Druggist, 1888, p. 32 ; A. H. Allen, in the Brit, and Colonial 
Druggist, 1887. p. 364 ; and Journ. Soc. Chem. Ind., 1887, p. 761. 


Vallin points out* that using 1 litre per day of a 5 per cent, 
solution of phenol for adding to excreta, Jrc, 50 grammes of phenol, 
or nearly 2 ounces, would be required daily for each patient This 
would be a large item of expense in a hospital, and even in those 
devoted to infectious cases, the consumption of carbolic acid is seldom 
a fraction of this quantity. 


The substitution in phenol of one or more of the hydrogen atoms 
by chlorine, bromine, or iodine can be easily effected by the action of 
these elements in the presence of water. Such substitution seems to 
increase the antiseptic power, but at the same time it causes the 
compounds to become much more unpleasant in odour, diminishes 
their solubility, and makes them more corrosive and very irritating 
to the eyes. 

Parachlorophenol, C,;H^0HC1, is a crystalline body, m.p. 33° C, 
soluble in sj)irit, ether, and fixed oils, and practically insoluble in 
water. It has been used as an ointment (2 to 3 per cent, with 
vaseline) in the treatment of erysipelas and lupus. 

A. Spengler also uses a 2 per cent, solution as an effective dis- 
infectant for the sputa of phthisical patients.f 

Hargreaves J manufactures " cblorophenols by the action of chlorine 
or hypochlorites on carbolic acid, tar, «kc., mixed with absorbents to 
form a disinfectant." 

Tribromophenol, C^iH.^BrgOH, is a white or brownish crystalline 
volatile substance, very insoluble in water, obtained by adding 
bromine water to phenol solution, when it falls as a white precipi- 
tate. It is interesting as a delicate test for phenol, and as a way of 
separating it from cresol, since tribromocresol is liquid. Both com- 
pounds have disagreeable odours, and are antiseptic, but too insoluble 
to be of much use. 

lodophenols are similar, but very unstable, being easily decomposed 
by light. Experiments with these comi)Ounds generally have not been 

Concentrated sulphuric acid acts on almost all the phenols, forming 
compounds soluble in water, and yielding soluble and crystallisable 
salts which are usually inodorous. In most cases two or more isomeric 
acids are formed, differing in characters. "When phenol is so heated, 
the ortho- and para-acids are formed. Their solubility, absence of 

* Disinfectants, p. .335. t Sem. Med., Oct. 31, 1894. 

:: Patent No. 18,460, 1889. 


odour, and the comparative harmlessness of the salts, have directed 
much attention to them as antiseptics. Their formation may be 
typified by the following equation — 

CeHjOH + S02<,gg = H2O + S02<^^«g^^ 

The salts in commerce were formerly called sulphocarbolates, 
or phenyl-sulphates. The sodium and zinc salts are in the British 
Pharmacopoeia. They easily crystallise and are inodorous. 

Sodium Paraphenol Sulphonate (" Sulphocarbolate") is a mild 
antiseptic, and is used in medicine for "disinfecting the intestinal 
tract." It is probably broken up in the body into phenol and 
acid sodium sulphate, each of which exerts an antiseptic action. 

CcHsNaSOi + HgO = CeHg.OH + NaHSOi 

The Zinc Salt, Zn(CgH40.HS03)2, has in addition the antiseptic 
and astringent properties of zinc. 

Vigier * who has studied the relative antiseptic value of the three 
isomeric phenol sulphonic acids, asserts that the ortho-acid is the 
most energetic. 

Sozo-iodol, a derivative of one of the di-iodophenols, obtained by 
combining sodium paraphenolsulphonate with iodine, is sparingly 
soluble in water, but easily soluble in alcohol or in glycerine. 
Its iodine is liberated by the action of light. It has been used 
locally in nasal and pharyngeal disorders, and in parasitic skin 

Sozo-iodol-mercury contains 31 -2 per cent, mercury and 38 per cent, 
iodine. + Draer has studied the action of both these compounds on 
the cholera bacillus.§ 

Aseptol is an ill-defined mixture of phenyl ethers and sulphonated 
phenols prepared by the action of sulphuric acid on phenol in the 
presence of alcohol. || 

Sozal is described by Dr. Schaerges of Berne, as aluminium para- 
phenolsulphonate (OQH^OHSOy)QAl.,. "It is a bactericide having the 
advantages in surgery that corrosive sublimate possesses, without 
its toxicity. It occurs in small crystals which have a strong 
astringent taste and only a slight odour of phenol. The salt is 
readily soluble in water and glycerine, and also in spirit." If these 
high claims are justified it will be of great value in surgery. 

* Joum. Pharm., [5], vol, xi., pp. 145, 214. 
t Brit. Med. Joum., 1889, vol. xi., p. 42. 

* Pharm. Joum., 1889, p. 577. 

§ Am. Journ. Med. Sci., March, 1894. 

II Serrant, Jahresherkht f. Thierchemie, 1885, p. 499. 



Hueppe describes a sulphonic derivative of phenol-orthophenyl 
sulphonic acid, which is less caustic and more antiseptic than the 
parent substance.* Kaemar f covers the use of certain sulphonatea 
as disinfectants. 

Benzene-Sulphonic Acid, S02(OH)CgH5, an acid liquid obtained 
by adding benzene cautiously to sulphuric acid with 30 per cent, of 
sulphuric anhydride, is patented by Giles and Shearer X as an 
antiseptic, disinfectant, and deodoriser. They minutely describe its- 
preparation and purification. It is a question whether it would be 
superior to sulphuric acid alone. It is the source of synthetical 
carbolic acid (p. 150). 

There are numbers of other sulphonic acids, but at present they 
have no special interest as disinfectants, but it will be noted that 
sulphonating reduces the poisonous action of both the hydrocarbons 
and the phenols without destroying their disinfecting properties^ 
Further comparative experiments with known organisms with the 
same weight of compound with and without a " sulphonic group "" 
would be of value. The sulphonates of hydrocarbons containing 
more than one closed chain should be especially active. 

Phenyl-substituted Fatty Acids. — Klein § showed that phenyl-pro- 
pionic acid has a niore powerful antiseptic action on anthrax bacilli 
than phenyl-acetic acid. J. Parry Laws || has further shown that 
phenyl-butyric acid restrains the growth of anthrax bacilli when pre- 
sent in the proportion of 1 in 2500, and that it kills the sporeless- 
bacilli when they are exposed for thirty minutes to a solution of 1 in. 
1000, or for ten minutes to a solution of 1 in 700. 

The followinji table shows the relative value : — 



Propionic Acid. 


Restraining Power, , 
Killing Power, . 
Length of Exposxire, . 

1 in 700 
1 in 200 
45 mins. 

not determined 
1 in 450 
30 mins. 

1 in 1900 
1 in 600 
30 mins. 

1 in 2500 
1 in 1000 
30 mins. 

Thus they increase in antiseptic power with of molecular 
weight. Duggan H has shown that the converse is true in the case of 
the fatty acids when tested on B. subtilis. His results give — 

Formic Acid. 
7 per cent. 

Acetic Acid. 
9 per cent. 

Propionic Acid. 
12 per cent. 

* Brit, Med. Joum., 1891, p. 1107; also on the Sulphocarbolates see Joum, 
Soc. Chem. Ind., 1889, p. 912. t Patent No. 3933, 1892. 

jPatent No. 14,864, 1887. § ThirUenth Annual Report L. C. B. 

II Chem. News, 1895, p. 15. IT .4m. Chem. Journ., vol. vii., p. 62. 



These percentages almost exactly correspond to their relative molecular 
weights, and consequently to their relative saturating power of bases. 


The higher phenols may be regarded as derivatives of phenol in 
which one or more of the hydrogen atoms of the " benzene ring " have 
been replaced by methyl or other fatty radicles. These substitution 
products form a homologous series of progressively increasing density 
and boiling point, of which the following are known : — 

Table of the Phexol Sebies. 

„ X .. ».. Commercial 
Systematic Name. Name. 


Rational Fommla. 

Phenol, . . . Carbolic Acid. 
Methyl-Phenol,., .{ gSjlirAcid. 
Dimethyl- Phenol, . Xylenol. 
Triniethyl-Phenol. . Cumenol. 
Tetramethyl- Phenol, , Durenol. 


} CyHgO 


CJI5 . OH 
CcH4(CH3) . OH 
C6H.,(CH3)2 . OH 

CbH2(CH3)3 . OH 

CcH(CH3)4 . OH 

Of all, except the first, several isomerides are known. They are 
all antiseptic ; as to their relative values the authorities differ, but 
.all agree that there is not much difference in power between phenol 
and the cresols. All dissolve in strong alkalies, giving soapy anti- 
septic solutions, but the compounds of the higher members of the 
series are decomposed by water, yielding milky emulsions which 
slowly deposit the oil. They are less poisonous than phenol, and are 
classed together as phenoloids. 

A mixture of these bodies from which phenol had been separated 
formerly constituted a waste product of the carbolic acid manufacture 
under the name of "creosote oils," and was used for preserving 
timber, &c. They are difficult to separate by fractional distillation, 
and now in various mixtures they are largely used for disinfectants 
under fancy names, such as Creolin, &c. Some of them contain also the 
hydrocarbons, or neutral tar oils. 

The waste gases from blast furnaces, formed by the destructive 
distillation of the upper layers of coal and bituminous iron ore, when 
cooled deposit large quantities of empyreumatic products, from which 
is manufactured on a large scale in Scotland the mixture called " blast- 
furnace creosote oil " for creosoting timber. It contains 20 to 35 per 
cent, of phenoloid bodies soluble in caustic soda, the coal-tar creosote 
oil made in London only containing 5 to 10 per cent. Watson Smith 
found one sample of the phenoloids obtained from blast-furnace tar to 
contain only 133 per cent, of phenol, having a boiling point of 182° C, 


while those obtained from Lancashire tar contained 65 per cent, of 
crystalisable carbolic acid (the phenol may have been previously 
separated from the former). The fraction that would contain cresol 
had 4 "5 per cent, of phenoloids, and the fraction boiling from 
210° to 230° consisted of a mixture of the xylenols and cresols. 
The " creosote oil " is treated with caustic soda, the insoluble 
hydrocarbon oils separated, and the soda compound decomposed by 
the waste gases from the furnace. Sodium carbonate is formed, setting 
free the phenoloids. The carbonate of soda is treated with lime, 
giving fresh caustic soda for another quantity of oil. The crude 
phenoloids are distilled, yielding the "creosote" of commerce. It 
contains about 1 to 2 per cent, of phenol, a large quantity of cresols, 
and a smaller quantity of the higher homologues. The oxyphenols, 
similar to those found in wood creosote, are present only in very 
small quantities. 

Schulze* has found in coal-tar cresols 40 per cent, meta-cresol, 
35 per cent, ortho-cresol, and 25 per cent, para-cresol. 

When fresh, creosote is almost as colourless as water, but it 
gradually darkens on keeping, slowly forming tarry products of less 
potency. It is quite as good an antiseptic as crude carbolic acid, 
and has not such a caustic action on the skin. 

Buchholtz states that the least quantity of creosote that would 
prevent bacteria from developing in Pasteur's fluid f was 1 in 2,000. 

Creosote has a strong power in checking fermentations, hence 
its name (xpsag, flesh ; ffw^w, I keep). Although only slightly soluble 
in water, its solution has preservative powers. It has been used for 
preserving organic putrescible liquids, and for keeping meat, &c., 
but its taste and odour are more unpleasant than those of the 
"creosote" from wood tar. It is administered internally to check 
fermentation in the stomach, but is a dangerous and unpleasant 
remedy, as it suspends digestion. Inhalations of coal-tar creosote 
vapour have no effect on phthisis, but are useful for cases of foetid 
expectorations arising from bronchiectasis (Chaplin). 

With reference to the antiseptic power of these creosotes, it has 
been asserted with some show of probability that mixtures have 
often been found to have more energy than any of the ingredients 
used singly. This may be due to the fact that different species of 
organisms have quite distinct susceptibility to different agents, 
Lacroix Hunkiabeyendian states that a mixture of ortho-, meta-, and 
para-cresol exerts a stronger action upon microbes {Staphylococcus 

* Ber. d. Chem. Gesells., vol. xx., p. 410. 

tlOgrms. sugar, 1 grm. ammoDinm tartrate, and 4 grm. potassium phosphate 
in 100 c.c. of distilled water. 



pyogenes aureus, Tetragonus prodigiosus, and the bacilli of cholera 
and typhus) than any of the purp compounds used singly,* As the 
solubility of the cresols in water is increased by the presence of a- 
small quantity of the sodium compound, there is therefore some excuse 
for the complicated nature of many of these patent specifications. 

Bacillite. — Hopef treats the sewage, &c., in suitable tanks with 
a current of "antiseptic steam" till deodorised (1). The antiseptic 
steam is generated from a solution of 1 gallon of "bacillite" (composed 
of cresylic oil 8 parts, sulphur ^ part, sodium hydrate 2 parts, sodium 
carbonate 1 part, resin 2 parts, boiled for two hours) "or other 
suitable disinfectant," in 200 gallons of water. "This quantity is 
sufficient to disinfect 4,000 gallons of sewage." But it will be noticed 
that most of the ingredients are non-volatile, and would not pass- 
over with the steam; in fact, the soda would hinder the cresol from 
volatOising. It would seem better to add the "bacillite" to the 
sewage and then pass in steam. 

Lysol, prepared by Schulke and Mayr, of Hamburg, is a brown 
transparent syrupy fluid which turns litmus blue "but contains no 
free alkali." The ash is about 6 per cent, and is mainly carbonate 
of potash. Lysol contains about 51 per cent, of volatile oils, consisting 
of higher phenols, and no carbolic acid. It is miscible with water in 
all proportions, hence it can be used of any strength. Dr. Schottelius | 
gives the minimum effective strength of the following in per cents. : — 




Staphylococcus pyogenes aureus. 
Typhus bacillus, .... 




Pearson's kreolin (Jeyes) was used. Lysol of 'SS per cent, destroyed 
in twenty minutes cholera and typhus bacilli. § The English patent for 
lysol II describes it as " tar oil mixed with a fat or fatty oil, and saponi- 
fied with alkali in presence of alcohol. Homogeneous and soluble." 

Lysol is thus a mixed disinfectant produced by dissolving in fat, 
and subsequently saponifying, with the addition of alcohol, the 
fraction of tar oil which boils between 190° and 200° C. (practically 
the cresols, excluding almost all the less soluble xylenols, &c.). It 
is a brown, oily-looking, clear liquid, with a feebly aromatic creosote- 
like odour. It contains 50 per cent, of cresols and is miscible with 

• /. de Pharm. et de Chemie, 1892. t Patent No. 17,924, 1891. 

J Miinchener Med. Wochenschr., 1890, No. 20. 

§ Engler, Dingl. pol. J., vol. cclxxviii., pp. 26 to 78 ; J cum. Soc. Chem. Ind., 
1890, p. 1,136. II Damman, Patent No. 1,017, 1890. 


water to a clear saponaceous, frothing fluid. It shows turbidity when 
mixed with hard water from the formation of the well-known preci- 
pitate of lime and magnesia soaps, but its disinfectant quality is not 
impaired thereby. It acts to all intents and purposes as a soap ; and 
seems well adapted for use in surgical operations. Lysol forms a clear 
solution with alcohol, glycerine, «kc. 

It removes all dirt, fatty and resinous spots from the skin, as well 
as from linen, instruments, and the like.* To remove the soapy 
feeling, the hands may be rinsed in sterilised water, and dried with 
a sterilised towel. 

Gerlach and Simmonds tried it on infected faeces with success. 
Cramer and others recommend it for surgery. Prom these reports 
lysol appears to be an efficient preparation for surgical purposes, but 
its mode of preparation would seem to make it too expensive for use 
in large quantities for public disinfection. 

Pixel {Eberman and Raptschev:ski) is made by slowly adding a mix- 
ture of 3 parts of tar and 1 part of "green soap," heating, if necessary, 
to 3 parts of a 10 per cent, solution of caustic soda. A clear brown 
liquid, miscible with water, results. " A 5 per cent, solution has the 
same power as lysol of the same strength, and is cheaper." The 
Lancet, Oct. 14, 1893, states that this disinfectant was found useless 
in the cholera wards of the Obrickooski hospital at St. Petersburg. 
The solution of tar does not kill cholera bacilli, and has only a slight 
inhibitory power on their growth. 

" Fizene " is a preparation of the same class, made by Wheeler from 
light tar oils. It mixes readily with water. 

The real question at issue is — Should a disinfectant be easily soluble 
in water or not? On the one hand, it is obvious that to penetrate 
through the envelopes of bacteria requires an agent which is in solu- 
tion, and therefore diflfusible. But Mr. Worrall, the inventor of the 
Thorncli£fe disinfectant, now called " Izal," takes exception to such a 
conclusion, and claims that " insolubility in water is one of the most 
valuable properties of this preparation, since when once applied to a 
part requiring disinfection it is not easily washed away, and therefore 
fulfils its purpose more effectively." 

There is no doubt that emulsions of tar oils have several sources 
of popularity with the public ; they look strong, their odour enables 
their presence to be felt, and their appearance enables one to judge 
when they are properly mixed, instead of falling to the bottom of the 
liquid, like solid disinfectants, or floating on the top and being carried 
away, like phenol. Moreover, the minute oily globules in these 
emulsions do slowly dissolve, and exercise a strong inhibitory action 
• Engler and Dieckhoff, Arch. d. Pharm., voL cczxx., p. 562 ; vol. ccxxxii., p. 351. 


on the germs for long periods of time, so that the sewage may be 
carried away before it has a chance of conveying infection. 

The best of these preparations may be regarded as strongly anti- 
septic and useful against infection, though it must always be remem- 
bered that, as Klein has pointed out in anthrax, Karlinski in excreta 
of typhus, and Kitasato in cholera stools, the matter apparently dis- 
infected, in which no growth may appear for days, if it be removed 
to fresh sterilised excreta [Kitasato), or inoculated into the blood of 
fresh subjects [Koch, Klein, Blyth, *tc.), will often begin to grow and 
prove fatal, the spores having been stupefied and not killed. 

Here the emulsified and slowly dissolving oil might have a distinct 
advantage, as, so long as sufiicient of it remained, the spores would be 
prevented from growing. 

Another soluble preparation closely resembling lysol is Tricresol, 
introduced by Scherings, of Berlin. It is a mixture of the three 
cresols found in coal tar — viz., the ortho-, meta-, and para-cresol — 
"has the advantage over carbolic acid of being non-toxic, and is 
superior to other cresol compounds in being soluble in cold water." 
Tricresol is synthetically prepared from toluene, CgH5(CH3). Accord- 
ing to Professor Gruber, water dissolves from 2-'l to 2-5 per cent, of 
tricresol ; but a 1 per cent, solution only is required in surgery, " that 
being equal in antiseptic power to a 3 per cent, carbolic acid solu- 
tion." * Tricresol is at first perfectly colourless, has the odour of 
creosote, and boils from 183° to 205° C, the fractions being — 
Below 183° = ... per cent. 

183° „ 185° = 4-3 „ 

185° „ 190° = 5-3 

190° „ 195° = 560 

195° „ 202° = 34-4 


" As phenol boils at 183°, and the cresols between this temperature 
and 202°, it follows that phenol, xylenol, and the other members of 
this series are practically absent. The specific gravities of the fractions 
are 1"04;2 to 1*049 at 20° C. It is stated to contain 40 per cent, of meta-, 
35 per cent, of ortho-, and 25 per cent, of para-cresol." The following 
table gives the physical properties of these three compounds : — 

Boiling Point Melting Point. 

Spec. Gravity. 

Orthocresol, . 
Metacresol, . 

191° 30° 
203° 4° 
202° 36° 





* Pkarm. Zeitung, 1894, No. 4; 1895, No. 97; Archiv.f. Hygiene, voL xvii,, 

p. 6ia 


Von Heyden asserts that the higher phenols are rendered soluble 
by mixing with sodium salts of acids like benzoic, salicylic, &c* 
The British Medical Journal, 1891, p. 414, states that a mixture of 
soluble tar products with sodium salicylate and water under the name 
of "resole" made a solution which was very effective. Engler and 
Dieckhoff have recently made an exhaustive examination of those 
cresol preparations which are soluble in water. f 

Among the emulsions containing cresols the more important are 
Jeyes' disinfectant and creolin. 

In the first patent I " resin and creosote or naphthalene are heated 
with .soda." Patent No. 5,249, 1877, proposes " coal-tar distillates 
above a 1,000 specific gravity" (this would include phenol and a large 
number of other bodies) "to be mixed with resin, soda, and vegetable 
oils" (giving a resin soap and a fat soap) "so as to make a milky emul- 
sion with water." An anthracene salt (?) or naphthalene also may be 
added. This very complex mixture seems to have been the original 
form of "Jeyes' disinfectant," a dark brown, syrupy liquid which gave 
a brownish-white milk easily diffused through water, a large proportion 
of the oils, etc., remaining quite insoluble. In its original form it 
had an unpleasant .smell and left dark tarry stains on the floorings 
&c. It has since been considerably improved, containing more of 
the cresols, and not so much of the naphthalene and neutral tar oils. 

Another application § melts together resin, naphthalene, and pitchy 
mixes with soda or potash, and makes into cakes, which are broken; 
up and dissolved in water when wanted. Unless there were a. 
great proportion of alkali, the "solution" in water would be very 
slow, and would require a great deal of stirring. 

It may here be mentioned that potash, the basis of lysol, saponifiese 
more rapidly than soda, and the product, being a soft soap, is more 
soluble than the hard soap made with soda. The mixture of the two 
alkalies is therefore advantageous. 

For drains, ifec, the fluid is directed to be mixed with 50 parts o€ 
water. It is also recommended for gargles (a teaspoonful to a pint), 
as spray, and for fumigation ; here it would have the same limitations 
as other preparations of slight volatility. 

That Jeyes' fluid and creolin are non-poisonous, or at least far 
less so than phenol, is proved by a recent case in London where a 
woman took 4 oz.s. of Jeyes' fluid with the object of committing 
suicide, but was not injm-ed. The British Medical Journal, Jan. 11, 
1890, also cites a case in which a man took nearly 9 ozs. of creolin 
with the same object. " He soon became unconscious, but waa 

* Patent No. 9,103, 1890. t Archiv. der Pharm., No. 232, pp. 351-365. 

* No. 4636, 1877. § Patent No. 2,669, 1882. 


discharged, cured, in the third week after admission." Such a result 
would have been impossible with carbolic acid.* 

Creolin is a more refined preparation by the same makers. It 
contains mainly the cresols as alkaline salts, without phenol or 
other tar products. It is a brownish-black alkaline syrupy liquid 
of empyreumatic odour, giving a soapy emulsion with water, f 

The bacteriological reports on these two fluids are very favourable. 
Dr. von Esmarcli in Koch's laboratory at Berlin found that " 1 per 
mille killed the cholera bacillus in ten minutes, whereas carbolic 
acid took four days." Dr. Eisenberg, of Vienna, states that 6 per 
cent, of it killed even anthrax spores in twenty-four hours, while 
phenol did not destroy them in a week. " Spores of the hay bacillus, 
which possess the greatest power of resistance, were killed by 6 per 
cent, of creolin in six days ; phenol failed. 

Dr. Washbourn J repeated the experiments of the two previous 
observers with confirmatory results. He concludes that "creolin is 
a good antiseptic, certainly superior to carbolic acid in its action 
on sporeless bacteria, and probably superior also when acting on 
spores." He finds that 5 per cent, creolin is equal to 1 per cent, of 
mercuric chloride. 

Oreolin and Jeyes' fluid have found great favour in hospitals for 
warm baths in infectious and skin diseases. Their results are certainly 
very good. But for sewage, fumigation, ttc, " disinfection" cannot be 
maintained, as it is proved by experiments that 5 per cent, is required 
to destroy all pathogenic organisms, and the cost of this would be 
almost prohibitive. 

Lano-creolin, soaps, gauze, &c., are also made, and "capsules" con- 
taining 5 minims each. 

" Smith's Carbolated Fluid " (Hampton Works, Borough Road, 
London) turns milky with water, and seems to be of similar nature 
to the above. So is " Artmann's creolin " (Julius Sommer, Stuttgart) 
specially used for soaps (Hof & Co., London Agents). 

The Strathclyde Chemical Company are manufacturers of a disin- 
fectant which is a residual product of a kind of blackstone shale at 
the Dorset mines. "This shale is remarkably light, yet it contains 
oils of a very heavy and volatile character. These oils when distilled 
are said to possess valuable insecticide and deodorant qualities.''^ 

These shale oils contain a large quantity of the pyridine series of 
bases to be described later (p. 189). 

Essets Fluid is an alkaline solution of higher phenols similar to 
Jeyes' fluid, giving, like it, a milky emulsion with water. The Lancet, 

* See ibid., 1891, p. 49, for a confirmatory case. t See Lancet, Jan. 5, 1889. 
J Guy's Hospital Reports, vol. xlv., 1888. § Chemist and Druggist, 1891, p. 39. 


July 1, 1893, pronounces it "an efficient disinfectant and antiseptic." 
It may be mentioned that the strength of solution recommended to 
be used for closets, drains, &c., viz., one teaspoonful to a gallon of 
water, or 1 in 320, is much too dilute to be efficient. 

Saprol, introduced by Dr. Nordlinger of Bockenhein, Frankfurt, is 
a dark brown oily liquid smelling like crude carbolic acid, having a 
mean specific gravity of 0'990, therefore floating on aqueous solu- 

According to the analysis of Dr. Spindler of Stuttgart, it contains 
phenol and cresol, 43-0 ; hydrocarbons, 53*9 ; pyridine and other bases, 
2-8 = 99-7. 

When poured into water a separation occurs, the heavier cresols 
partially dissolving and partially sinking in drops, while an oily scum 
of the hydrocarbons floats on the liquid. This covering, according to 
Professor Quincke of Heidelberg, amounts to 0*2 milligramme per 
square millimetre. Scheurlen* finds that when saprol is thus poured 
upon water, and left to stand for three or four days, from 33 to 39 per 
cent, of it dissolves — that is, the greater part of the cresol and phenol, 
of which it contains 43 per cent. The liquid contained 0-41 to 0*49 
per cent, of cresols. He proved that either crude phenol or saprol 
itself, even if .shakei repeatedly for seven days with water, only yielded 
solutions of 0"45 to 0'51 per cent, of cresols, so that he concludes that 
0*5 per cent, is the mean solubility of the cresols, and that the latter, if 
time be allowed, dissolve just as well when merely poured on water, 
as when continuously and vigorously stirred. " This fact, applied to 
the disinfection of faecal matters, proves that by the use of saprol a 
mixture of the faeces supersaturated with the disinfectant is obtained." 
Dr. H. Gross found that the addition of dilute alkalies or acids did 
not increase the solubility. It is also pointed out that while the 
uniform coating of saprol entirely prevents contact with the atmo- 
sphere, so that no evil-smelling gases can be emitted from the faeces, 
the usual oxidation process is also checked, while the soluble parts of 
the saprol gradually penetrate right through the mass. 

According to Laser,! a thin layer of saprol kept urine clear, without 
smell and sterile, for twenty-two days. A thick layer sterilised 
anthrax cultures in twenty-four hours. Urine, which had been stand- 
ing under a thin film of saprol for twenty-three days, was filtered and 
mixed in three glasses with (1) cholera vibrios, (2) typhus bacilli, 
and (3) Staphylococcus pyog. aureus. In all three glasses the micro- 
organisms were killed. He also made a series of researches with 
increasing quantities, to ascertain the amount required to disinfect 
and deodorise urine, and, as a result of his experiments, concluded 

♦ Archm.f. Hyg., 1893. t Centr.f. Bacteriologit, 1892, toL xiL, p. 78. 


" that 1 per cent, of saprol is sufficient for the disinfection of fseces 
and urine." 

Scheurlen * confirms these results. It must be remembered that a 
1 per cent, solution of saprol is equivalent to about 0*34 per cent, 
solution of the cresols. 

The special claim of saprol is its peculiar physical action — viz., 
" being a little lighter than water, partially soluble and partially 
insoluble " — by which it — 

1. Forms a complete coating over the substances, so keeping them 
from the atmosphere, and masking smells. 

2. Diffuses gradually and evenly through the putrescent matters, 
first restraining and then killing the organisms. 

3. Acts in less strength (1 per cent.) than phenol (2i per cent.). 

As to cost, it is stated that " 1 litre per month, costing 60 pfennige, 
is sufficient for a household of twenty people, or 3 pfennige per month 
per head." 

It must be admitted this is a very strong case for saprol. It 
and lysol are much used in Germany, the former for common, and 
the latter for surgical purposes. It is to be noted tliat saprol retards 
the n£.tural decomposition of sewage by oxidation ; unless the excreta 
be removed quickly they will be liable to grow organisms again, as 
even with such cheapness it would be difficult and expensive to attain 
so high a strength as 1 per cent. A similar reservation applies to all 
this class ; they are really more antiseptic than true disinfectants, and 
their action as deodorants is simply that of a mask. 

The presence of pyridine (which is very soluble) must not be for- 
gotten. Neither sulphuretted hydrogen nor ammonias would be 
effectively absorbed ; hence it would be advisable to use one of the 
chemical absorbents as well. 

The flashing point of saprol is 90° to 100° C, about the same as that 
of phenol, and sufficiently high for safety under ordinary circum- 
stances. Unless heated, a light applied to it does not cause it to 

In some of these preparations containing the higher phenols, ozone 
is said to be produced when they are exposed to the air. 

With Allen's " hygiene disinfecting fluid " this is said to be the 
case, but as this fluid is recommended to be used at a strength of 
1 in 500, and the evidence of all experiments go to prove that 1 per 
cent, is the lowest effective dilution for any tar preparations, these 
statements require confirmation. 

As to the production of ozone, Dumas f endeavoured to explain the 
slight deodorant properties of the tars in the light of the experiments 
♦ Arch. f. Hyg., 1893. t Acad, des Sciences, July 25, 1859. 


of Schonbein on the abundant formation of ozone in air mixed with 
the vapours of essence of turpentine, but later experiments have shown 
that in all probabilitj' more hydrogen peroxide than ozone is jjroduced 
by the phenols in the presence of air and moisture. 

IzaL — In the process of carbonising coke in close ovens, a tarry oil 
condenses, which contains some of the higher phenols. From it 
J. H. Warrall has obtained . a clear deep, reddish-brown liquid 
insoluble iu, and of greater density than, water. Its mean boiling 
point — i.e., it is a mixture — "is considerably higher than that of 
carbolic acid (400° F.), and it has not the caustic action on the skin 
as has that antiseptic ; moreover, it is non-poisonous to the higher 
animal life." This insolubility and high boiling point " insures the 
antiseptic body remaining upon the part requiring disinfecting after 
it has once been there deposited." It remains permanently suspended 
iu water, forming a milk-white emulsion, and is hence easily distri- 
buted by water. " It remains liquid at all temperatures above 32° F., 
while a temperature of 212° F., instead of deteriorating, only tends to 
concentrate it. It mixes readily and perfectly with water in all 

It was originally called the " Thorncliffe disinfectant," but is now 
known under the name of "izal." 

Mr. "Warrall tried izal on the Acarus of the sheep, and found one 
treatment to effect complete cure, "proving that not only were the 
parents destroyed, but the antiseptic body remained to destroy also 
any insects hatched from the eggs which the parents had deposited 
previous to their death" ("the time of egg-incubation and larva-develop- 
ment is ordinarily fifteen days"). This seems to be a far more legitimate 
inference than that the eggs themselves had been destroyed. 

Klein, after a bacteriological investigation, reported that izal had 
"a quite remarkable bactericidal effect." According to Dr. Klein, 
0'25 C.C. administered to a rabbit, both subcutaneously and by the 
mouth, had no effect on the rabbit's health or appetite, and Mr. 
Warrall states that 10 drops have been taken with impunity. 

Dr. Klein states that "an exposure for five minutes to izal in the 
strength of 1 in 200 completely destroys the vitality of the microbes 
of diphtheria, typhoid, fowl-cholera, swine fever, glanders, cholera, 
suppuration, erysipelas, scarlatina, and other non-sporing pathogenic 
and non-pathogenic species." 

With reference to spores he continues: "The result of all experi- 
ments on inhibition may be briefly summarised for all the twenty-five 
species tested — namely, (1) spores do not germinate in medicated 
gelatine or broth if the amount of disinfectant added be 01 per cent.; 
(2) no microbes (Staphylococcus and Streptococcus) are capable of grow- 


ing in medicated gelatine or broth of the strength of O'l per cent. 
medication ; (3) all non-sporing bacjlli and spirilla fail to grow in the 
above 0-1 per cent, fluid; (4) excepted from this are the Bacillus 
prodigiosus and the bacillus of typhoid ; the former shows growth on 
gelatine medicated 0*1 percent.; the growth is retarded, and always 
starts from the superficial layer of the medium ; it proceeds consider- 
ably slower than on normal gelatine." 

Dr. Bruce Clarke, of St. Bartholomew's Hospital, gives a very 
favourable report of its use in surgery.* With regard to Dr. Klein's 
•exceptions he says that they " obviously do not concern one from a 
surgical point of view, inasmuch as B. prodigiosus is not a pathogenic 
•organism at all, and the bacillus of typhoid fever does not enter 

He also observes that, " being an emulsion and not a clear solution, 
it is not so easy to see one's instruments when they are covered with 
it. At the same time it must be borne in mind that the very fact that 
the fluid is so singularly unable to form chemical compounds with 
living animal tissues is in all probability highly advantageous from the 
germicidal point of view. Unlike corrosive sublimate, which speedily 
loses its disinfectant power by combining with the albuminous sub- 
stances of the body, izal retains this power in such a remarkable degree 
•because it will not combine with anything. It is also at the ordinary 
temperature of the body non-volatile, as may be easily seen by placing 
a few drops on a piece of cotton wool and leaving it several months in 
an exposed position." It is to be inferred that : — 

(1) Izal seems, in a strength of 1 in 200, to be a disinfectant, and in 
1 in 1,000 to be more antiseptic than phenol. 

(2) Not being volatile it must be strictly local in its action, 
like chloride of zinc. Hence it is doubtful if to "saturate a sheet 
and suspend it before the door of a room" has much beneficial 

(3) The quantities recommended, namely, "for sprinkling rooms, 
1 tablespoonful with 5 pints of water," and for sewers and public dis- 
infection, " 1 gallon in 100 gallons of water," are higher than those 
usually proposed for most other "disinfectants," being about 1 per cent. 
As Dr. Rohe says,t "There can be no partial disinfection of infectious 
material ; either its infective power is destroyed or it is not. In the 
latter case there has been a failure to disinfect, and the labour and 
money have been wasted." 

As a warning, however, it must be remembered that even the 1 per 
cent., when used for sewage, becomes considerably diluted ; hence a 
great deal more must be used. Here the expense, as with other disin- 
• Lancet, July 1, 1893. t Text Book of Hygiene, 1890, p. 350. 


fectants, become so heavy that, at the risk of repetition, it must be 
laid down that the practical and complete disinfection of sewage by 
any agent or process at present known cannot bo attained except at 
great cost. 

Lawes' disinfectant fluid and " Odamine " are similar commercial 
cresol products used as disinfectants and sheep dips. 

Europhene, isobutylcresol hydriodide, (CgH3(CH3)(C4H9)OH)2,HI, 
is a product of the action of iodine on isobutyl-orthocresol. It is 
insoluble in water and alkalies, but soluble in alcohol and ether. It 
easily decomposes (liberating iodine), and behaves like similar organic 
iodine compounds. 

Resorcinol, or "resorcin," is meta-dioxy-benzene, CgH4(OH)2. It 
is prepared by fusing sodium m-benzene-disulphonate with potash or 
soda and extracting with alcohol. 

Resorcinol occurs in minute needles, colourless when pure, but 
turning reddish in air. It coagulates albumen, forming a white 
precipitate. It only begins to be toxic in very large doses 10 to 
20 grammes per day internally for an adult, while a 2 per cent, 
solution is highly antiseptic (Vallin). 

Andeer * Callias f Dujardin-Beauraetz J Lichtheim of Berne, and 
others have experimentally demonstrated that resorcinol is a powerful 
antiseptic. Callias proved that fermentation was prevented, and 
many animal liquids preserved, by 1 per cent, of resorcinol, while 
to keep milk required at least 2 per cent. 

As to its internal action, Andeer, after a dose of 10 grammes of 
resorcinol, experienced vertigo, dizziness, loss of smell, and salivation, 
the symptoms disappearing in 5 hours with no after effects. It is 
therefore, far less poisonous than phenol. Dr. W. Murrel§ has also 
reported on its internal use. 

Dujardin-Beaumetz employed the fine powder in diphtheria and in 
syphilitic ulcerations with somewhat doubtful results. 1^ per cent, 
of resorcinol gradually entirely sterilised the bacilli of typhoid. 

It is evident that 1 per cent, of this substance is efficiently antiseptic 
towards most micro-organisms. It has been employed in the treatment 
of acute fevers, also as spray in diphtheria and whooping-cough. As 
an antiseptic the dose is 5 to 20 grains. 

Andeer's lotion is resorcinol 40 grains, water 1 ounce, as an anti- 
septic and stimulant for foul sores and to allay chronici eczema and 

psoriasis. II 

* Ueber daa Resorcxn, Wurtzburg, 1880. 

t Resorcxn en TMrapeutique, Paris, 18S1. 

X Bull, de TMrapeutique, June and July, 18S1. 

§ Med. Times and Oaz., 1881, p. 486. 

li Squire'8 Companion to the B. P., 1890, p. 348. 


For rendering rooms antiseptic M. Meilliere* recommends the dissi- 
pation of phenols, &c., by heat. Napbthalin, anthracene, xylol, ordinary 
phenol, cresols, naphthols, benzoic acid, oxybenzoic acid, salol, betol, 
beuzonaphthol, chloral, formal, and mercury sulphides and chlorides 
are indicated as useful for this purpose, but resorcin is particularly 
recommended. It is best mixed with a little hydrochloric acid, and 
the mixture should be heated in an open dish. Afterwards it is well 
to evaporate rapidly 100 grms. of water, either pure or acidulated with 
acetic or hydrochloric acid. 

Pyrocatechol or pyrocatechin, ortho-dioxybenzene, CgH4(OH)2, is 
obtained by fusing iodophenol or iodosalicylic acid with potash. Like 
almost all products of destructive distillation it is antiseptic, but its 
properties in this respect do not seem to have been studied. The 
third dioxybenzene hydroquinone or quinol has also an antiseptic 
action, but is not much used. 

J. E. Dugganf has investigated the relative antiseptic power of the 
three dioxy benzenes by noting the amount required to prevent Bacillus 
suhtilis from developing in beef peptone. Taking phenol as 20, he finds 
that the ratio of the three compounds ortho : meta : para = 20 : 25 : 30, 
whilst pyrogallol is represented by 15. 

Pyrogallol or " pyrogallic acid " is trioxybenzene, CgH.5(OH)3. It is 
obtained by distilling gallic acid. It is inodorous, tastes astringent, 
and is not corrosive. Its solution quickly turns brown in air, absorb- 
ing oxygen ; if an alkali be present, the action is almost instantaneous, 
the solution becoming dark brown. This property leads it to be 
destructive to "aerobic" organisms — those which live in presence of 
oxygen. Bovet, of Neuchatel, first examined its antiseptic action, J 
and found that a 2 per cent, solution prevented putrefaction, ferment- 
ation, and mould for some months, and that 3 per cent, was capable of 
killing bacteria. Two per cent, solutions have no injurious local action 
and disinfect very well ; but it cannot be used internally, as it reduces 
and destroys the blood corpuscles, causing hsemoglobinuria. It blackens 
steel instruments and stains the hands. The British Medical Journal 
recommends a 2 per cent, solution as an antiseptic (1879, vol. i., p. 278). 
"A 10 per cent, salve applied with a brush twice a day has been 
recommended in psoriasis, § but Neisser records a fatal case where it 
had been used freely as an ointment.|l 

* Journ. de Pharm. [6], vol. i. , p. 82. 

+ Amer. Chem. Journ., vol. vii., p. 62. 

X Revue cChygiSne, 1879, p. 154. 

§ Journ. of Pharm., vol. xxv., p. 377- 

II Zeilschri/tf. klin. Med., 1879, vol. i., p. 88; Squire's Companion, 1890, p. 27. 



The substances which are formed during the destructive distillation 
of wood in closed vessels are very numerous. They vary with the 
nature of the wood and with the temperature of the distillation, and 
are gaseous, liquid, and solid. Charcoal, of course, is left behind in 
the retorts. 

It may be mentioned here that the gaseous products of destructive 
distillation of all organic bodies are antiseptic in nature, and many 
proposals have been made to utilise them by blowing them through 
sewage, &c., but the action is not sufficiently energetic. 

The liquid portions are partly soluble in water. Wood spirit or 
crude methyl alcohol, CH3OH, is obtained from them by distillation ; 
it is strongly antiseptic, but is so volatile and inflammable that it is 
best used for other purposes. 

Pyroligneous Acid (discussed under Acetic Acid, p. 225), with methyl 
acetate and acetone, are also among the volatile products. 

The insoluble portion, which consists of wood-tar, is composed of a 
mixture of various liquids, such as the hydrocarbons, toluene, xylene, 
cymene, «fec. (the same as those from coal-tar, p. 148, but with little or 
no benzene), the substance called wood-creosote, and solids, such as 
paraffin, naphthalene, &c. The lower the heat used, the larger is the 
proportion of oxidised bodies formed, and the smaller that of hydro- 
carbons and gases. So that various specimens of wood-tar difier in 

It is probable that many of the coal-tar disinfectants previously 
described contain wood-tar products also. 

The proportions of the different bodies obtained by distillation of 
wood are approximately as follow : — 

Charcoal, 25 

Gases, 22 

Wood spirit, 1*0 

Acetic acid, 4*0 

Tar, 7-5 

Water and other bodies, 40*5 


Stockholm Tar, obtained from the resinous wood of the pine, is 
extensively used for preserving ropes and sacking. The smell is prin- 
cipally due to the constituents of creosote, notably to the crystalline 
body called pyroxanthin, which, though only present in small quantity, 
is said to be one of the best preservatives. Stockholm tar contains 
much resin, acetic acid, and oil of turpentine. When distilled it 


leaves a black resinous substance which constitutes ordinary pitch, 
and has been used in many patents for forming solid block disinfect- 
ants. The specific gravity of the ordinary wood-tar of commerce is 
about 1 "04 ; when poured on water a portion floats and some dis- 
solves, like saprol. 

Retinol is simply the product of distillation of ordinary resin. Its 
antiseptic properties are feeble. 

Resol is the name of a disinfectant which has been introduced from 
Germany. It appears to be similar to creolin. It is made by saponi- 
fying 1,000 parts of wood-tar with 9 parts of caustic potash, and adding 
200 parts of " an indifierent body such as wood-spirit." (The latter 
would, on the other hand, add considerably to its antiseptic power and 
aid in the saponification.) Resol is said to be an active bactericide, 
killing typhoid, anthrax, and similar bacilli in five or ten minutes with 
a 3 per cent, solution. 

Wood Creosote contains some phenol and cresol, and quantities of 
oxyphenols like guaiacol, creosol, and a little pyrocatechol. It is more 
antiseptic than coal-tar creosote, and has a different and more agreeable 
odour, but a more burning taste. It immediately coagulates albumen. 
It is not easily inflamed, but when kindled burns with a smoky 
flame ; it has been proposed to mix it with spirit and burn it in lamps 
for fumigation, but the sooty flame so produced retards its use. If 
swallowed in doses of more than a few drops it acts as a poison, so that 
its internal administration must be attempted with caution. Though 
sparingly soluble in water, the latter acquires from it its peculiar 
odour, pungent taste, and much of its antiseptic power. Alcohol and 
acetic acid dissolve it freely, so do the hydrocarbons of tar. 

It combines with potash to form a crystalline compound ; solutions 
of soda and ammonia also dissolve it. It is one of the most powerful 
antiseptics known. Meat that has been plunged into a solution con- 
taining 1 per cent, of creosote gradually becomes dry and hard on 
exposure to air, and acquires the flavour of smoked meat, but does not 
become piitrid. A considerable proportion of creosote (from 1 to 1^ 
per cent.) is held in solution in the crude pyroligneous acid obtained 
during the destructive distillation of wood ; and on saturating this 
acid at 167° F. with effloresced sodium sulphate, an oily matter which 
contains a large proportion of creosote is separated. Crude pyrolig- 
neous acid on this account is often employed for preserving hams and 
salted provisions, to which it communicates the same flavour as if they 
had been exposed to wood-smoke. 

A great many patents relate to the manufacture of a disinfectant by 
distilling peat; this would be mainly creosote. Unfortunately the 
yield is small. 


Creosote is used for carious teeth, for foetid ulcers, and in many 
cutaneous affections, especially those tliat are parasitic. 

J. Sommerbrodt, after nine years' trials, gave a most favourable 
account of its action in tuberculosis. In doses of 1 to 4 grains per day, 
in capsules with cod-liver oil, " it is well borne by the stomach and 
does not decrease the appetite." * If applied to the skin in a concen- 
trated state it produces a white spot like phenol, and the skin peels off" 
without any attendant inflammation. Creosote dissolves many organic 
bodies, such as camphor, the fatty and volatile oils, and many of the 
resins. Therefore it has been a frequent ingredient in compound 
antiseptic preparations. It is much more costly than the coal-tar 
product, hence could not be employed largely in public sanitation ;. 
and its smell in some cases has been known to produce nausea, head- 
ache, and vomiting. 

Reichenbach in 1830 discovered the antiseptic powers of creosote;, 
after a long period of trial it fell into discredit, and now is only 
employed for the uses above mentioned.! 

Plants watered with creosote solution at once die ; hence it cannot 
be used as a horticultural insecticide. Most micro-organisms are killed 
by it in a strength of ^ per cent., and their spores are prevented from 
developing. In very small quantity it prevents fermentation, the 
action of diastase on starch, &c. 

Bucholtz asserts that " 1 in 1000 was not sufficient to sterilise 
vegetable infusions ; it required 1 per cent, to completely sterilise 
germs and bacteria." 

Guaiacol, methoxy-phenol or methyl-pyrocatechol, CgH4(OCIl3)OH,. 
is a colourless liquid, becoming brown in light (therefore should 
be kept in non-actinic bottles). Its odour and taste resemble creosote,, 
of which it constitutes a large portion. It boils at 200° 0. Only 
i per cent, of it dissolves in water, but it is more easily soluble in 
alcohol, wood-spirit, acetic acid, and in alkalies. Sodium-guaiacol 
resembles sodium-phenol. 

Ferric chloride gives a brown opacity with the aqueous, and a. 
blue colour with the alcoholic solution; hot sulphuric acid gives an 
orange coloration. On shaking 4 c.c. of guaiacol with milk of lime 
(10 grammes lime in 10 c.c. of water) white crystals of a lime-guaiacol 
compound slowly form. 

As the antiseptic value of wood creosote is due partly to the 
guaiacol which it contains, it is important to note that recently this 
ingredient has been removed from foreign creosotes. 

* Berlin. Klin. Wochenschr., Oct. 19, 1891. 

tSee a monograph by M. Labb^e in the " Dktionnalre des Sciences Medicodet,^' 

art. Creosote. 


The largest quantity (60 to 90 per cent.) exists in beech-wood 
creosote, but it also has been obtained by distillation of guaiacum 
resin, whence the name. 

Its physiological value was first pointed out by Seidel in 1880 
P. Marfori * finds that 1 part of guaiacol should dissolve in 60 of 
water, and that impurities render it more soluble. It first excites, 
then paralyses the nerve-centres, and reduces the temperature. Thera- 
peutically it is similar to phenol and pyrocatechol, but not so poison- 
ous. In a later paper f the same author states that its antiseptic 
power is greater than that of phenol in the ratio of 5 to 2, and that 
•0"5 to 1 per cent, destroys Bacillus ttibemdosis in two hours, while 
other bacteria are killed with their spores in 20 to 30 minutes. 

The hypodermic solutions known as Picot's, Pignol's, and Morel- 
Lavallee's contain guaiacol. 

It has been used for phthisis, administered in cod-liver oil or in 
^vf^•lk spirit. 

Guaiacol-carboxylate, C6H3(OH)(OCH,).COOH, is obtained by 
saturating sodium guaiacol with carbonic acid, heating, and pre- 
cipitating by hydrochloric acid. It is, therefore, a methoxy-salicylic 
acid, and has naturally been credited with antiseptic and antipyretic 

Creosol, or methyl-guaiacol, C^H,j(CH3) (OCH.j).OH, is the chief 
ingredient of ordinary wood-creosote. It resembles guaiacol, but has 
a higher boiling point, is heavier, and less soluble. Its antiseptic 
power is said to be a little higher. 

A comparative study of creosol, guaiacol, and wood-creosote, with 
and without the low boiling guaiacol, would be of value. 

A disinfecting fluid called "soluble creosote," containing some 
wood-creo.sote, is in the market. § 

"Little's Soluble Phenyls," made by Morris of Doncaster, was at 
one time in high repute in the north of England. It is recommended 
by Dr. Rohe as a good disinfectant at a strength of 2 per cent.|| Prof. 
•Corfield after lengthy experiments spoke highly of it. "It is non- 
corrosive and non-poisonous. 1 per cent, in water is more powerful 
than 10 per cent, of the best known antiseptics for wounds, ulcers, 
and for use at post-mortems. The powder is also energetic against 
vermin." It appears to be derived from wood-tar creosote, and would 
take rank with the other preparations. 

* Chem. Centralblait, 1890, p. 155. t Ann. dl Chimica, 1891, vol. xiii,, p. 3. 
i See also Benzosol, chap, ix., p. 197. § Chem. and Drug., Oct. 26, 1893. 
II Robe's Hygiene, 1890, p. 326. 



According to Bucholtz, diphenyl compounds or bodies containing 
two carbon " rings," are more powerfully antiseptic than those 
containing only one such grouj). The toxic behaviour of such com- 
pounds is also diminished. 

Naphthalene itself, CjQHg, has been already described (p. 148). It 
is useful as an insecticide, but is not a disinfectant. It is employed 
locally in scabies as a 10 to 20 per cent, solution in olive oil. It is 
to be avoided where large surfaces are exposed. It is also used as an 
antiseptic for wounds. Dr. Mirovitch considers naphthalene of high 
value against ascarides and tape-worm, in doses of 15 grains, followed 
by a large dose of castor oil.* 

Some commercial " disinfecting powders " have been proved to 
contain little else than naphthalene and earthy matters. It is hardly 
necessary to say they are of little value. 

Helbing states f that " the observations of Pavas, Dor, Hess, 
Magnus, and Kolinski, among others, led to the conclusion that 
naphthalene is unsuitable for use in medicines. It acts injuriously 
on the optic nerves and the retina, and upon the kidneys. A small 
quantity of camphor is said to largely cover its odour without affecting 
its value as a preventive of moth."| Tidy advocated the presence 
of naphthalene in the creosote used for preserving timbers. 

Naphthalene-sulphonic acids, CjoH7(S02. OH). — By heating naphtha- 
lene with concentrated sulphuric acid, two isomeric acids of this 
formula are obtained. They are deliquescent crystalline substances, 
soluble in water and strongly acid, and almost inodorous. The a-acid 
changes into the /S-form when further warmed with suli)huric acid. 
The resulting mass is dissolved in water, saturated with chalk, and 
the lime salt crystallised (the a-salt remains in solution). Addition of 
sodium carbonate will then convert it into the sodium salt, which 
has been occasionally used as an antiseptic. 

Naphthols, CjqH- . OH. — Each of the above sulphonic acids, when 
fused at a moderate temperature with caustic soda, yields the corre- 
sponding naplithol. These are purified by pressure, distillation and 
crystallisation from hot water or petroleum ether. 

a'Naphthol resembles the /3-form closely, but melts at 95° and boils 
at 279° C, and with hot ferric chloride gives a violet colour. 

^•Naphthol, as being more abundant, is the commercial article. It 
crystallises in lustrous plates, smells like phenol, and has a hot and 
tarry taste. It melts at 122° and boils at 286° C, and gives a green 

* Lancet, 1891. + Modem Mat. Med., 1891, p. 64. 

X See alao Fischer, Med. Times and Oaz., 1881, p. 718. 



tint when heated with ferric chloride. Both the naphthols are readily 
volatile with steam. The crystals should be colourless, should not 
darken in light, should be neutral, and leave no ash on platinum. 
It is almost insoluble in cold water, but dissolves in about 1 1 parts 
of boiling water, in 2 of rectified spirit, in 1 g of ether, 24 of chloroform^ 
12 of olive oil, and in 4 of glycerine. It is a powerful antiseptic, and 
was first proposed for skin diseases by Kaposi in 1881. It has been 
given internally in diarrhoea in an emulsion with oil, and is very 
effective in parasitic diseases and in chronic eczema* in ointment form 
(3 to 10 per cent.), or in alcohol solution (2 to 10 per cent.) (Helhing). 
A daily dose of 38 grains will produce intestinal antisepsis. It has 
also been used in typhoid fever, f A solution of 1 in 1,000 has been 
successfully used for preserving anatomical preparations. 

Prof. Bouchard, in a report to the Academie des Sciences in 1888, 
detailed certain experiments on the antiseptic power of /3-naphthol. 
He says that he found 0*4 grm. of it to have the same efiect as '025 
grm. of mercuric iodide, 2 grms. of phenol, 1"6 of creosote, 1*27 of 
iodoform, 27 of iodol, or 1-51 of naphthalene. J He values it highly 
for external use. "But what is more important is, that it appears to 
be the most efficient agent for intestinal antisepsis, on account of its 
slight solubility, which prevents its absorption, and allows it to 
remain a long time in the intestine without any poisonous effects. 
A dose of 1 grm. per kilo, of body-weight may be administered without 
danger." § 

Lesser and Neisser recorded symptoms of poisoning by jS-naphthol, 
which Shoemaker attributed to impurities ; a conclusion largely con- 
firmed in 1888 by an exhaustive examination of this drug by Willing.|| 

Dr. A. G. Gibson,1I of the Edinburgh Medical Infirmary, used 
2 grains of /3-naphthol two or three times a day for the antiseptic 
treatment of pernicious anaemia. In a large number of cases, im- 
provement was extremely rapid when iron had been used before. 
Dr. Gibson finds that irritation is sometimes caused by the drug, and 
to prevent this he administers it together with a bismuth preparation, 
such as the salicylate. 

It has been recently observed that a-naphthol and salol (p. 199) 
when rubbed together form a liquid. /3-naphthol, on the other hand, 
does not liquefy, but, like many other substances, it becomes a 
permanent fluid when melted with camphor, so forming " camphorated 

• Med. Times and Gaz., 1882, vol. xi., p. 505. 
+ Brit. Med. Journ., 1888, vol. xi., p. 1226. 

J The experiments make naphthalene a stronger antiseptic than phenol, Year 
Booh ofPharm., 1888. § Brit. Med. Journ., 1888, p. 1185. 

II Helbing, Mod. Mat. Med., p. 53, IT Edin. Med. Journ., October, 1890. 


)8-nap]ithol," used, according to Fernet, with great success for boils, 
coryza, angina diphtheritica, and tuberculosis. Against the latter it 
was given by injection in doses of 2 grms. mixed with oil. 

Reboul cured twenty -one out of twenty-seven cases of tuberculous 
glands by emptying any abscess formed, and injecting 7 or 8 drops of 
camphorated naphthol, repeated every two days. Similar results are 
recorded by Nelaton.* 

Betel, naphthol salicylate, CgH^(OH).CO.OCiQH-, is a white, crystal- 
line, inodorous, and tasteless powder, neutral, insoluble in water and 
in glycerine, difl&cultly soluble in alcohol and turpentine. It dissolves 
in 3 parts of hot alcohol, in ether, benzene, and in wanaa linseed oil. 
Melting point, 95° C. Hot acids or alkalies reconvert it into salicylic 
acid and iS-naphthol. It is prepared similarly to salol (p. 199). Anti- 
septic ; now almost disused. 

" Microcidine," chiefly composed of sodium-/3-naphthol, OjoHyONa, 
also contains phenols. * Prepared by the action of soda and heat on 
/3-naphthol. It is more soluble but less antiseptic than the latter, and 
is somewhat irritant and caustic. It possesses no special advantage. 

"Alumnol." — By heating the naphthols with sulphuric acid, several 
naphthol-sulphonic acids are obtained. Certain of these, saturated 
with aluminium hydroxide, give an aluminium salt to which the above 
name is applied. Alumnol contains 5 per cent, of aluminium. It is a 
white stable powder, very soluble in water, and soluble in alcohol with 
a blue fluorescence. It dissolves in glycerine, but not in ether. It is 
slightly acid. With albumen and gelatine it forms precipitates which 
are readily soluble in excess. " Judiciously employed it produces no 
injurious effects. Very large doses are required to produce any toxic 
action on animals." t 

Prof. Eraud, of Paris, praises it highly as a dressing in simple 
wounds, in ulcers, and as an injection in gonorrhoea; also the powder 
as a dry dressing. He finds it to cause neither irritation nor pain. J 
"As a soluble non-toxic astringent, strongly penetrating and antiseptic, 
it seems to deserve a place. Excellent results have also been obtained 
by using solutions of ^ to 5 per cent, in laryngitis and pharyngitis. 
Dr. A. Spengler, of Heidelberg, considers alumnol quite equal to zinc 
chloride, while it has the advantage of not being unpleasant to use."§ 

Hydronaphthol seems to be /3-tetrahydro-naphthol, CjqHjjO, obtained 
by the reduction of /3-naphthol by sodium. It forms white shining 
crystals with an odour something like creosote, slightly soluble in 
water, easily in spirit. Dr. Bryce recommends the external use of 
1 part of hydronaphthol dissolved in 10 parts of rectified spirit, to 

* Helbing, loc. r'U. t Heintz and Liebrccht, Pharm. Centraihalle, 1892, p. 697. 
X Chem. and Drug., Jan. 21, 1893. § Lancet, April 21, 1894. 


■which sufficient glycerine is added to make a 1 per cent, solution. 
"In this form the antiseptic properties are well marked." Dockrell 
has used it very successfully in a plaster against 7'inea tonsurans. 
Mr. M. Clarke found it of great value in enteric fever and diarrhoea. 
He says that it has a very distinct retarding effect on digestion, but 
does not much interfere with that of milk. 

Hydronaphthol gauze 5 per cent, is recommended as very lasting, 
and as compatible with albuminous fluids.* 

a-Hydroxynaphthoic Acid, called also simply oxynaphthoic acid, 
CiQHg(OH).COOH, is formed by the action of carbonic acid on sodium- 
naphthol. It melts at 186° C, is sparingly soluble in water, but easily 
•in alcohol, ether, and the alkalies. 

Collodion impregnated with ^ per cent, of it has been used as a 
substitute for iodoform-collodion, as it is non-irritant and more stable.! 
EUenberger and Meister established its bactericidal properties. A 
5 per cent, ointment is antiseptic in scabies. Its salts are not antiseptic. 
It has not been determined whether it is completely innocuous. | 

" CMoronaphthalene" and "naphtholeum" are used for disinfecting 
excreta in one of the London districts. 


Nitre-Compounds : Nitro-Benzene — Nitro- Phenols — Trinitio Phenol or Picric 
Acid ; its value as an insecticide — Nitro-Cresols — Nitro- Glycerine — 
Nitro-Cellulose — Collodion. Amido-Compounds : Ammonia — Compound 
Ammonias or Amines — Amides — Amido- Acids — Imido-Compoiinds — 
Hydroxylamine — Hydrazine — Methylamine — Dimethylamine — Trimethy- 
lamine — Propylamine — Amylamine — The " Amines Process" — Aminol — 
Aniline — Acetanilide or Antifebrin — Aniline Dyes as Antiseplics — Methyl' 
Violets — " Pyoctanin " — Researches on their Antiseptic power- Apyonin. 
Pyrrol- Compounds : Furfurane — Thiophene — Pyrrol — Jodol or Tetia-Iodo- 
Tyrrol—Antipyrin or Phenazone— Salipyrin, &c. Pyridine Group, &c. : 
Conine — Piperine — Pyridine — Antiseptic properties of Tobacco-smoke — 
Nicotine — Various Patents as to Pyridine, &c. — Indole — Tryosine — 
Quinoline or Leucoline — Diaphtherin — Loretin — Thalline — Quinine — Anti- 


The aromatic nitro-compounds are characterised by their poisonous 
properties. Several of them have been suggested as disinfectants. 

* S. W. Williams, Chem. and Drvg., 1893, p. 735. t Ibid., 1889, p. 34. 

J i/bum. o/Soc. of Chem. Industry, 1888, p. 226. 


Nitro-Benzene (" Nitro-Benzol "), C8H5(N02), is a heavy yellowish 
oil with an odour like bitter almonds. It is a disinfectant, because it- 
kills bacteria, but its poisonous character and insolubility render it 
unsuitable for general use. Pettenkofer and Lehmann* state that 
the vapour of nitro-benzene " even in large quantities had no serious 
effect;" but many aniline workers have experienced that it is 
nauseating and narcotic. The same may be said of Nitro-Toluene, 
CgH4(CH3)(N02)5 <fec., and the di- and tri-nitro-corapounds. 

Ortho- and Para-Nitrophenols, CgH^(N02)0H, are obtained by 
acting on phenol with nitric acid. Both are slightly soluble in 
water, acid, germicide, and poisonous. Their sodium compounds are 
soluble and antiseptic. There are no records of bacteriological experi- 
ments with reference to them. 

Trinitrophenol, "picric" or "carbolised acid," CgH2(N02)30H, is 
easily produced by the action of nitric acid on nearly all organic 
bodies that contain the benzene nucleus. It occurs in pale yellow 
plates, and is very acid, little soluble in water (about l^ per cent.), 
but soluble in alcohol. Its salts are yellow and explosive. 

It is a very powerful germicide ; it almost immediately combines 
with albuminoid substances, staining them yellow, precipitating the 
albumens, and causing the death of protoplasm in exactly the same 
way as iodine ; hence it is rapidly fatal to both bacteria and spores. 
It does not, however, like iodine, permanently colour starch and 
cellulose. The aqueous solutions are extremely poisonous, irritant, 
but not corrosive. 

Jalan de la Croix f found that bacteria in white of egg infusions 
were killed by 1 in a 1,000 of picric acid, but resisted 1 in 5,000. He 
also points out that a solution of 1 in 200 prevents growth in bouillon, 
while i to 1 per cent, was required to destroy the germs ; this would 
be a nearly saturated solution in water. Cheron I disinfected the 
latrines of a hospital by the use of 10 litres of a saturated solution, 
(li per cent.). He found that it arrested fermentation, and the 
action of diastase and synaptase. The germination of seeds was also 
prevented. It hindered the ammoniacal change in urine, even in 
cases of vesical catarrh, when given to a patient, or injected into the 

Schwartz asserted (1880) that a minimum dose of 1 in 15,000 of 
l)icric acid killed the bacteria of tobacco infusions transferred to 
Pasteur's solution, whereas Kuhn maintained that 1 in 1,000 was 
necessary, thus agreeing with Jalan de la Croix. 

Picric acid is used in histology for hardening and preserving tissues. 

* Acad. d. Wiaaeiuch. zu Afiinchen, 1887, p. 179. 
t Arch./, exp. Pathol., Jan. 27, 1881. t J. eU Thirapeu'., Gnbler, 1880, p. 121. 


Vallin states * that 60 centigrammes per day produce in man, besides 
a deep orange colouration of the skin and urine, a slowing and 
weakening of the heart, prostration of sti*ength, vertigo, and stupe- 

Kinloch has recently patented picric acid as " an insecticide," anti- 
septic and disinfectant.! 

Except as an insecticide, when its staining powers and poisonous 
action on plants and animals would be against its use, picric acid may 
be pronounced to be unsatisfactory for disinfection. There is still, 
however, a possibility of its being of special service in killing those 
micro-organisms that only mercuric chloride will touch, as Klein 
has shown, with some difficulty. Further experiments would be 

Potassium Dinitro-Ortho-Cresol, OgHo(N02)2(OH3)OK, occurs in 
yellow needles, inodorous, sparingly soluble in water, poisonous, and 
explosive by heat. Therefore, it is used as a yellowish paste, mixed 
with soap and glycerine, and thus dissolves easily in water. It has 
been lately introduced into this country under the name of " Anti- 
nonnin " (F. Bayer & Co., Elberfeld). " Properly diluted it forms an 
efficacious and safe insecticide, and does not injure plants. Though 
originally intended to destroy certain kinds of caterpillars it has been 
found to be fatal to mice, ants, snails, and all kinds of plant-lice, as 
well as protecting wood from dry rot and fungi. 1 kilo, of antinonnin 
in 300 litres is found most effective for killing lower plant life and 
fungi. House and field mice succumb to three-twentieths of a grain, 
best mixed with flour-paste." | The specification states that " 1 in 400 
of water kills all insects, also fungi which rot timber; it may even be 
«ised more dilute if time be given. Soft soap, ^ part, increases the 

There are a large number of other nitro-compounds of the aromatic 
group, of similar properties, but of no special interest. 

Nitroglycerine, 03115(0.1^02)3, is said to be antiseptic when dissolved 
in alcohol and poured into water. 

Nitrocellulose dissolved in ether or acetone is used under the name 
of Collodion for protecting wounds, &c. Being insoluble in water and 
the blood fluids, it has no antiseptic power. 


Ammonia, NH3, has been described among the alkalies (p. 109). It, 

like the other products of putrefaction, is fatal to the bacteria which 

produce it, and the bactericidal power of ammonia, sulphuretted 

hydrogen, and even of carbonic acid no doubt materially assist in 

* Disivfectants, p. 156. t Patent No. 6,243, 1894. t Patent No. 3,301, 1892. 


retarding natural decay. Animal matter placed in a 5 per cent, 
solution of ammonia remains free from putrescence for a long period. 
When added to gelatin in which putrefaction had been already set up, 
& 5 per cent, solution caused the putrefaction to cease. In an atmo- 
sphere impregnated with ammonium carbonate, meat can be kept for 
six months, and at the end of the time remain unaltered. 

In all these cases it is necessary that the material be kept closed, 
or the ammonia would rapidly escape. On account of its alkalinity, 
smell, and irritant action, it has not been much used. The fact that 
its vapour, which is at first stimulant, soon becomes excessively de- 
pressant, also militates against its use for rooms. The compound 
ammonias, or amines, formed by replacing successively the atoms of 
hydrogen in ammonia by basic organic radicles, have greater antiseptic 
properties. Methylamine, NH2(CH3), the simplest of these amines, is 
a gas ; others are more or less volatile liquids ; while the more compli- 
cated organic bases, like the alkaloids, are white solids. They are all 
alkaline, form salts with acids, and the volatile ones have an ammoniacal 
odour. As a class they are poisonous, therefore they are antiseptic 
and may be disinfectant. They absorb sulphuretted hydrogen, but of 
course do not absorl^ ammonia. 

The acid organic radicles, such as acetyl (CH3.CO), may also replace 
the hydrogen in ammonia, forming a class of bodies called amides, e.g.^ 
a^etamide, CHg.CO.NHg, which are usually crystalline, neutral com- 
pounds which are soluble in water and more or less volatile. A few, 
like acetanilide, are antiseptic. 

Hydroxylamine, NHgOH, has been tried by Bing and others in skin 
diseases. It acts as a reducing agent and is a strong germicide. 

Hydrazine or Diamine, NgH^, has been found by Loew and Buchner 
to be powerfully poisonous to animal, vegetable, and bacterial life. 

Methylamine, CH3NH2, is a gas with a strong alkaline reaction- It 
is more basic and more soluble in water and in alcohol than ammonia. 
Its odour is like that of herring-brine, in which it is contained. The 
hydrochloride, (CH3)NH2.HC1, crystallises in deliquescent, very solu- 
ble plates, which give off methylamine on treatment with potash. 
The sulphate forms an alum, (CH3NH2)2H2S04, Al2(S04)3, 24H2O; 
this is a powerful disinfectant, but has not been much used. 

Dimethylamine, (CH3)2NH, occurs in guano and, in small quantities, 
in pyroligneous acid. It resembles the preceding. Neither of them 
seem to have met with any practical application. 

Trimethylamine, (CH3)3N, is a very volatile, alkaline, and inflam- 
mable liquid, extremely soluble in water and alcohol. It also has the 
fishy and ammoniacal odour. It is obtained from herring-brine, and 
is made in large quantities, with ammonia, dimethylamine, methyl 


alcohol, and methyl cyanide, by distilling " vinasse," a residue of the 
beet-sugar manufacture. The source is " Betaine," the internal anhy- 

dride of trimethyl-amido-acetic acid, CH2.00.0.N'(CH3)3. 

In Patent No. 16,242, 1888, H. Wollheim claims its use "for de- 
stroying, in a very short time, the vitality of all germs and spores 
which can produce disease." Its compounds with acids crystallise 
well, and resemble the ammonia salts, but are more soluble in alcohol, 
and are said to be poisonous. 

The Ethyl- and Propyl- amines are similar, but of greater density and 
higher boiling point. Propylamine, (C3H7^)NH2, is metameric with 
trimethylamine, and resembles it. 

Amylamine, (C5H^-)NH2, is contained in the products of destructive 
distillation of animal matters, such as bone oil. It is a liquid smelling 
like burnt feathers, is antiseptic, but seems to have no special advantage. 

The Amines process for treating sewage consists in the utilisation 
of herring-brine with lime. This liquid is a mixture of amines, with 
trimethylamine predominating. Klein and others, who tested the 
effluent bacteriologically, reported very favourably on the process, 
asserting that the result was complete sterilisation, that 1 per cent. 
of trimethylamine was sufficient, and that the operation was easy 
and inexpensive. Objections were made by others on the score of 
(1) the offensive odour of the precipitant; (2) its deterioration on 
keeping ; (3) in the case of its application inland, the quantity of salt 
that must be discharged into rivers ; (4) the danger of the effluent 
being poisonous to river-fish (this is not proved of the small quantity 
of trimethylamine that would remain as, being volatile, most of it 
evaporates into the air) ; (5) the alkaline character of the clarified 
water; and (6) the difficulty of procuring a sufficient supply of herring- 

"Aminol" is the name given to the mixture of methylamines 
obtained by distilling herring-brine with lime according to the patent 
•mentioned above. It is a clear colourless liquid, alkaline and odorous 
of the bases. It is permanent when kept tightly enclosed, but easily 
loses strength when opened. Two solutions are applied : — " D " 
(disinfecting) for general disinfecting purposes, is said to be a "perfect 
deodoriser, non-poisonous, non-corrosive, and does not stain;" and 
"R" (Remedial), for medicine and surgery, "efficient remedy in all 
suppurative, phlegmonous, or fermentative disease processes." 

Aniline, CgH5(NH2), amido-benzene, is now made on a large scale 
by the reduction ot nitrobenzene by iron filings and acetic acid. The 
residue, acetate of iron, is oxidised to "red liquor," ferric acetate, 
and has been used in France as a disinfectant. Aniline also occurs 
in bone-oil (p. 190). 


It is an oily liquid, colourless when pure, but turning brown in air 
and light, boiling at 184° C, but easily volatile with the vapour of 
water. Its melting point is 0-8° C, and specific gravity 1'036. It is 
soluble in 31 parts of water, very soluble in alcohol, <fec., and forms 
soluble crystalline salts from which the base is again liberated by 
potash, soda, or lime. 

It is poisonous, and hence a germicide. It slowly volatilises at 
ordinary temperatures, giving a vapour of oppressive tobacco-like 
odour, which also kills bacteria, but does not easily affect their spores, 
Pettenkofer and Lehmann assert* that 0-1 per cent, of aniline vapour 
in air is dangerous to man and animals. From this fact, and the slow 
rate at which it diffuses, its use for fumigation is negatived. 

The salts are antiseptic, and, being acid, absorb ammonia and com- 
pound ammonias, but not sulphuretted hydrogen. Angus Smith t 
places aniline in his sixth class — i.e., as moderately antiseptic. Dr. 
Fischer has shown that tubercular sputa mixed with ten times its 
volume of aniline water, is completely disinfected in twenty-four hours. 
This is equivalent to the action of a 5 per cent, carbolic acid. At the 
present price of aniline, it seems to be a disinfectant which is worth 

Substitution Products. — An immense number of these have been 
obtained, aniline being much more easily acted upon than benzene. 
They are generally antiseptic, but have hitherto not yielded any satis- 
factory results for hygienic purposes, and are less soluble and volatile, 
and often more poisonous than aniline itself. 

Acetanilide, " antifebrin," or phenyl-acetamide, CgH5.NH(CO.CH3), 
prepared by boiling aniline with glacial acetic acid for several days, is 
a white crystalline and easily soluble powder. Its melting point is ll^** 
(Ritsert), and boiling point 295°, Potash and acids slowly reconvert 
it into acetic acid and aniline. In 3- to 8-grm, doses it is antipyretic 
and analgesic in fevers ; externally it has been used as an antiseptic 
for wounds, but 30 grains in twenty-four hours has been found to 
produce poisonous symptoms. A special therapeutic commission! pro- 
nounced it inferior to phenacetin and antipyrin (p. 189). 

Para-brom-acetanilide, " asepsin," or " antisepsin," 


is said to be anodyne and antiseptic. This must not be confounded 
with "aseptin." 

Aniline Dyes as Antiseptics. — Several of these have long been known 
to have the power of penetrating into living animal and vegetable 

* Acad. d. WUsenach. zu Munchen, 1887, p. 179. 

t DxHxnftctanU, Edin., 1869. % Brit. Med. Joum., 1894. 


structures, different dyes selecting different parts and species ; there- 
fore, they are widely employed for microscopic staining. Their action 
occurs in extremely dilute solutions, and is out of all proportion to 
their poisonous action on higher animals. 

The effect is to lower the vitality of, and, finally, to kill the organ- 
isms. Hence it became a matter of interest to see how far they could 
he used as actual disinfectants. 

Koch proved* that a number of the tar dyes were inhibitory to 
tubercle and other bacilli, both in local and in internal application. 

The Methyl Violets are mixtures of hexamethyl-rosaniline hydro- 
■chloride — 




virith the salts of penta- and tetra-methyl rosanilines. They occur in 
amorphous, dark blue masses (the pure hexa-compound is in large 
deep violet crystals), soluble in alcohol, sparingly in water, but gives 
it an intense violet colour. 

Professor Stilling, of Strasburg, has experimented on the disinfect- 
ing power of methyl-violet, and has found that a paste made with 
wheaten flour, with a 2 per 1,000 solution of methyl-violet added, 
■does not turn sour, however long it is kept. Milk mixed with the 
same quantity does not turn sour, butter and bacon soaked in a 
stronger solution (1 in 500) and dried, become superficially stained, 
but do not afterwards become rancid. Mucor stolonrfer was sown 
upon rolls of bread, some of which were soaked in a 1 in 500 to 1 in 
1,000 solution of the dye, and some in water only. On the latter a 
growth appeared in twenty -four hours, whilst on the former none 
could be noticed after fourteen days. He has given the name of 
■" pyoctanin," from croog, pus, and xraog, stain, to methyl violet, and 
says it can be had absolutely pure from the firm of E. Merck, of Darm- 
stadt. " Certain auramines proved to be the next best, when used in 
solutions of 1 in 4,000 to 1 in 1,000." f 

Dr. C. Prioux J points out that solutions of pyoctanin and gentian 
violet, 1 in 100 prevent the development of micro-organisms. Weaker 
solutions (1 in 500, or even 1 in 2,000) arrest the cultures of typhoid 
and Bacterium coli communis (the ordinary microbe of the intestines) ; 

* Mittlieil. a. d. K. Gesundh., 1881, vol. i., p. 234. 

t Lancet, 1890, vol. xi., p. 965. 

X International J. of Microacopy and Nat. Science, vol. iii., part 18. 


1 per cent, solutions of safranine (an orange-red dye containing at 
least three " benzene rings ") have also been shown to hinder Eberth's 
bacillus from developing. 

Solutions of blue pyoctanin for general surgery, ointments, powders, 
and dressings have been introduced. 

Dr. Petersen found that these preparations were as effective as 
those made with iodoform, without the unpleasant odour, and without 
any bad effects or symptoms of poisoning. Dr. Wanscher strongly 
recommended a 1 per cent, solution for ophthalmic use and in urethral 
dischai'ges, as lessening local irritation. They have also been used for 
nasal and other cavities of the body, to stop suppuration. Von 
Mosetig treated malignant tumours by injections of methyl violet, and 
believes that complete cure by this method is possible. 

Yellow Pyoctanin is an " auramine," obtained by acting on dimethyl- 
aniline with phosgene, and then by ammonia; its formula is 
0[CgH4. N(CH3)2]2- NH. It is a para-derivative of benzophenone, 
and is specially recommended for ophthalmic practice. 

<< Apyonin" is said to be also an auramine, and is intended for the 
same purpose as the last. 


There are other rings analogous to the benzene ring, but containing 
4 or 5 atoms instead of 6. Those with 4 carbon atoms include these 
three chief compounds : — 

Furfurane. Pyrrol. Thiophene. 

CH = CH. CH = OH, CH = OH 



OH = CH/ OH = CH^ CH = CH 

All three are tar products, are volatile, colourless liquids, with 
antiseptic characters that have not been well studied. 

Furfurane, C^H^O, is a mobile liquid with an odour like chloroform, 
and boils at 32° 0. It appears to be present in pine-wood tar, 
together with methyl-furfurane, or sylvane, C4H3(CHg)0, which boils 
at 63° C. 

Furfurol, C4H3(CO.H)0, is the corresponding aldehyde, and is 
formed by the action of acids on sugar, bran, «fec. {Furfur, bran). 

Thiophene, C^H^S, is found in commercial benzene, and smells like 
it ; it boils at 84° 0. It is probably an insecticide if not a germicide. 
It is insoluble in water, but soluble in oil of vitriol, forming a 
sulphonic acid, 04H3S(S03H). 



Pyrrol, C^H^(NH), is colourless, but becomes brown in air (like 
most of these bodies). It boils at 133° C, has a specific gravity of 
1*077 {Atiderson), a faint odour like chloroform, and a hot, burning 
taste. It is insoluble in alkaline solutions, but is slowly dissolved by 
acids. It is contained in coal tar, but is generally made from bone 
oil. Alcoholic solutions of pyrrol precipitate mercuric chloride. 

"lodol," tetra-iodo-pyrrol, C4l4(NH), is made by the action of iodine 
and potash on pyrrol. It is a pale yellow, inodorous and tasteless, 
crystalline powder, almost insoluble in water, soluble in 18 parts of 
alcohol, 155 of glycerine, 1^ of ether, and in oils. It decomposes at 
140° C. with violet vapours of iodine. It gives a black precipitate 
with mercuric chloride (hence incompatible with it), and is decomposed 
by hydrochloric acid, iodine being liberated. It is reputed to have 
antiseptic properties, and is used for the same purposes as iodoform, 
but has not the objectionable smell, and is not so poisonous, but 
Riedlin says * that it has no action on cholera or any other bacteria. 

" Antipyrin," OjiH;^2-^2^' — -^7 substituting a nitrogen atom for one 
of the (CH)'" groups in pyrrol, the grouping known as pyrazol, 
C3H3.N.NH, is obtained. A body of ketonic character called pyra- 

CH :N\ 
I > NH, 


is an oxy derivative of this compound. From it phenyl -methyl - 


qCHg) : N \ 
I >N(C,H,); 

CH2.C0 X 

and phenyl -dimethyl -pyrazolone or "antipyrin"; abbreviated in the 
British Pharmacopoeia to "phenazone" are obtained — 

CH = CH 

CH = CH' 


CH = N 

CH = CH' 

CH = N . 



CH.,- CO 

Phenyl-methyl-pyrazolone. Phenyl-dimethyl-pyrazolone (antipyrin). 

C(CH3) = N ^ C(CH3) - N(CH3)^ 


CH2 — CO^ CH — CO 

* Archxv.f. Hyg., vol. vii., p. 309. 




L. Knorr's patent* heats phenyl-hydrazine, NH2.NH(OgH5), with 
ethyl aceto-acetate, OH^(CO . CH3) . CO . 0(C2H5), when water and 
alcohol are separated, and phenyl-methyl-pyrazolone formed ; methyl 
iodide converts this into antipyrin. 

Antipyrin, or "phenazone," crystallises in colonrless scales, neutral, 
inodorous and slightly bitter, fairly soluble in water, alcohol, and 
chloroform, less so (about 1 in 50) in ether. It dissolves in acids to 
colourless solutions. Melting point, 113° C. It has been found 
mixed with acetanilide (p. 185), which is much cheaper; but the 
detection is easy, as, although the melting point of the latter is also 
about 113°, a mixture of the two melts about 45° C. It is antipyretic 
and antiseptic, also an anodyne for neuralgia and gout (see Antifebrin, 
p. 185). Externally, it has found favour as an antiseptic lotion, and 
as gauze. It is incompatible with tannin, many acids, ferric salts, 
iodine, and a number of drugs. 

Nitro- and " isonitroso "-antipyrin, " salipyrin " (a salicylate ), 
*' iodantipyrin " or " iodpyrin," " resopyrin " (a compound with 
resorcinol) have been prepared. 


If, in the benzene ring, nitrogen be substituted for a CH group, 
pyridine, C^H^N, is obtained. From naphthalene and anthracene, 
similar nitrogen derivatives are formed : — 



/ ^^ 

!l I 





/ \ 









^ \ /' -^ 



\ / \ .< 






/" \ / \ 








^ \ / \ 



















s / \ / \ 




S / \ 




Additive compounds, of which piperidine or hexahydro-pyridine, 
CjHjqNH, and nicotine or hexahydro-dipyridy), (C5H4N)2Hg, are 
examples, are also known. The radicles, methyl, ethyl, <J:c., can 

* Liebig'a Annalen, voL cczxzviii., p. 137. 



also replace the hydrogen atoms giving homologues of pyridine, which 
exist with it in coal-tar, and in larger quantity in bone-oil. They 
much resemble pyridine in properties, but rise in boiling point and 
diminish in density as the number of carbon atoms increases, and are 
more readily oxidised and attacked. The mono-, di-, tri-, tetra-, and 
penta-methyl derivatives have been obtained by the fractional distilla- 
tion of bone-oil, the fractions so procured being mixtures of isomerides, 
■which it is impossible to separate by this method. They were dis- 
covered by Anderson in 1846, and investigated also by Greville 
Williams, Ladenburg, and others. 

Table of the PyRiDiNE HoMOLoonEs. 





Name. Formula. 






117° C. 





































Conine, OgH^^-^j ^^^ volatile alkaloid of hemlock (Conium macula- 
turn), is normal-propyl-piperidine, C5H^qN(C3H-), (Ladenburg). 

Piperine, from pepper, is peperyl-piperidine, OjHjqN - CjgHgOg, 
related to pyridine through piperidine (ibid). 

It will be noticed that aniline, CgH5(NH2), is metameric with the 
picolines, 0^114(0113)1^, of which all the three possible isomerides have 
been separated from bone-oil. 

All these substances are more or less narcotic poisons ; hence, would 
act as antiseptics, and, if in sufficient quantity, would kill bacteria. 
It has been mentioned that Saprol (p. 165) contains pyridine bases: 
from most coal-tar disinfectants they have been removed together with 
aniline by treatment with acids, but some of the newer preparations 
contain appreciable quantities of these bases. The most important is — 

Pyridine, O5H5N. — Wlien pure it is a mobile, colourless liquid, 
which does not turn brown in air and light, and is slowly and com- 
pletely volatile. Its odour is said to be " empyreumatic," but is most 
persistent and unpleasant. It absorbs water from the air, and mixes 
with it in all proportions ; it is also readily soluble in alcohol. It 
forms soluble crystalline salts with acids. Oommercial ammonia often 
contains pyridine, and commercial pyridine is sometimes contaminated 
with ammonia. 


Tobacco-smoke, contrary to popular belief, does not contain nicotine, 
■which is decomposed by the heat, but pyridine and its homologues, 
and the beneficial efiect of tobacco in many cases of asthma, must be 
attributed to these latter, whether as sedative or as bactericide (it 
must be remembered that very little of the smoke itself gets into the 
lungs). Pyridine inhalations have been proposed for asthma. "From 
1 to 1| drachms are poured on a plate and placed in a rOom with the 
patients. At 68° to 77° F. the above quantity evaporates in about an 
hour. It is said that after a few minutes' exposure to the pyridine 
atmosphere the remedy can be detected in the urine. The treatment 
was well spoken of by Dr. Keleraen, among others, but does not seem 
to have maintained its ground. Mixed with a little oil of peppermint- 
it has been employed in the treatment of diphtheria with some 
success, and in aqueous solution (1 in 300) three or four injections 
have been recently said by Rademacher to be sufficient to cure 
gonorrhoea." * 

It was stated by the Cigar Manufacturers' Association of Hamburg^ 
that in the last visitation of cholera there were only eight cases and 
four deaths amongst a body of 5,000 cigar-makers. 

Dr. Burney, the senior Medical Officer of Greenwich Workhouse, 
asserts that the to'bacco-smoking inmates enjoyed comparative im- 
munity from epidemics, and tobacco-smoking is believed to have had 
a disinfectant action in cases of cholera and other infectious diseases. 
But Dr. Kerr points out that if a man canncrt stand smoking it may 
depress his heart action and enfeeble his constitution, and so lessen 
the resisting power to throw off the noxious germs. Pyridine fumi- 
gations are also open to the same objection. It is recorded that 
Tessinari found that tobacco-smoke, on being passed through tubes- 
containing a nutrient gelatine and pathogenic germs for from ten te 
thirty minutes, destroyed the bacilli of Asiatic cholera and of pneu- 
monia. Pyridine was introduced by O. Fergusson as a horticultural 
insecticide about 1890, but its odour was against it, although it was 
most effective. Wynter Blyth exposed the yellow bacillus of nasal 
catarrh, on threads, to the action of a 1 per cent, solution of a mixture 
of pyridine, coUidine, lutidine, and acridine from bone-oil. After the 
threads were washed and transferred to nutrient gelatine, there waa 
no growth. In sour milk also, pyridine inhibited growth. Tobacco- 
smoke passed through water killed the yellow bacillus. These experi- 
ments tend to confirm the idea that disinfectant preparations containing 
the basic constituents of coal tar are to be preferred to those only 
containing the phenols, also that pyridine being very soluble in water 
and non-irritant, might be of service in nasal affections. 
• Helbing, Mod. Mat. Med., p. 65. 


Nicotine, CjQH3(Hg)N'2, is an oily liquid which rapidly turns brown 
in air. It boils at about 250° C, but is readily volatile with steam. 
It has a well-known stupefying odour, is alkaline, dissolves easily in 
water, alcohol, and ether, forms crystalline salts with acids, and is 
extremely poisonous. Its use as an insecticide in gardening is familiar. 
At Greenwich in 1893 the use of tobacco seemed to be protective in 
an epidemic of English Cholera. 

Nickels* covers the use of shale or bone-oil, or pyridine bases, with 
resin and soda, as a disinfectant. 

Overbeckf proposed the use of pyridine or leucoline (quinoline, see 
below) with chalk or lime. 

Indole, CgH^<^^-rT ^CH, crystallises in plates, moderately soluble 

in water, easily in alcohol and ether, melting at 52° C, feebly basic, 
having a peculiar fsecal odour, and giving a red colour or precipitate 
of nitroso-indole with sodium nitrite and dilute sulphuric acid. It 
readily volatilises with steam. As a product of putrefaction it has 
been presumed to be antiseptic, but its odour would preclude its 
practical use. It has derived a certain importance from the fact that 
it is constantly formed in the growth of the bacillus of typhoid and 
the spirillum of cholera. BujwidJ first proposed the "indole test," 
as given above, to distinguish these pathogenic organisms from others 
that are innocuous. But unfortunately Bacillus coli communis, which 
is commonly found in the intestines and in water contaminated with 
normal fcEces. also forms indole, as might be expected from the latter 
being always present in small quantity in the intestines. 

Tyrosine, CgH4(0H).CHo(NH._,).C00H, iS-oxyphenol-amidopropionic 
acid, is also a constant product of the putrefaction of albuminoid sub- 
stances, and has been said to be strongly antiseptic. It crystallises 
in minute needles, which are inodorous, almost tasteless, and nearly 
neutral. It seems to be worthy of experiment. 


Quinoline, chinoline, or "leucoline," C,jIl7.N, is a colourless, highly 
refracting, oily liquid of a disagreeably pungent and aromatic odour, 
and a bitter acrid taste. In light and air it rapidly turns brown. It 
melts below 4° C, boils at 237° C, and has a specific gravity of 1"081. 

It dissolves sparingly in water, easily in alcohol, &c., to an alkaline 
solution, and with acids forms soluble crystalline salts. The salicylate 
and tartrate have been used in medicine, both internally and ex- 
ternally. Quinoline occurs in coal-tar, &c., with two homologues, 

• Patent No. 3,053, 1883. t Patent No. 3,199, 1883. 

:;: Zeit.f. Hyj., 1887, vol. xL, p. 52. 


lepidine, CjoHgN, B.P. 265', and cryptidine OnH^iN, B.P. 274' C. 
Quinoline is incompatible with oxidants, with iodine solutions, and 
with metallic salts ; it is antiseptic, and is the subject of the following 
patent* : — " It has been proved that quinoline and toluquinoline 
possess great antibacterial properties, but the complete insolubility 
of these substances in non-acid fluids presented a serious obstacle to 
their use. This invention consists of using as a solvent soap in the 
nascent state," as in creolin, &c., "50 kilos, of castor oil, 50 of quinoline, 
by the clearing of the liquid, which is then diluted with 85 kilos, of 
water," Quinoline does not saponify, so that the solution would 
contain 20 per cent, of quinoline dissolved in aqueous soap, and would 
become turbid with water like creolin. 

" Diaphtherin " was introduced by Prof Emmerich and Kronacher, 
of Munich,t who, after extended trials, pronounced it to be " equal, if 
not superior, to previously known antiseptics." It is said to be di-oxy- 
quinoline phenolsulphonate, 2C9H^(OH)N,06H4(OH).HSO3. {Ortho- 
phenol-sulphonic acid, or "aseptol," p. 158.) It is a yellow powder, 
readily soluble in water, decomposed by alkalies and even by blood, 
with elimination of sparingly soluble oxyquinoline in a fine state of 
division ; hence, whei;i applied to wounds, it does not lose its antiseptic 
power as some phenolic substances do (it does not coagulate albumen). 
Emmerich administered 0'25 gramme subcutaneously to guinea pigs, 
without prejudicial results. "A 1 per cent, solution is sufficient for 
antiseptic dressings." 

a-Oxy-quinoline or carbostyrile, C9H^(0H)N, occurs in white 
needles, melting at 198°, and is strongly antiseptic. It is the source 

"Loretin," iodo-oxy-quinoline sulphonic acid, C9H5l(OH)N.HS03, 
lately introduced as another substitute for iodoform, and reported on 
by Prof Schinzinger, of Nuremberg. He showed that its action on 
granulating and healing processes is a very favourable one, and is 
superior to that of iodoform, while it is free from objectionable odour, 
not toxic, and non-irritant, and rapidly removes any eczematous 
tendency. It is also a good deodorant of purulent secretions and 
decomposing tissues, "It is very beneficially employed to combat 
external and parasitic diseases, and as an antiseptic may be blown 
into cavities for internal affections." 

Quinoline when reduced forms a tetrahydride, CgH^^N, which is 
more strongly antiseptic than quinoline. 

"Thalline" is para-methoxy-quinoline tetrahydride, C3Hio(OOH3)N. 
According to the specifications (Skraup, 1885) it is made like quinoline, 

• No. 18,913, 1S91 ; Lembach, Schleicher, and Wolff. 
t Munch. Med. Wochemchr., 1890. 



by heating methoxy-aniline (para-amido-anisol) with glycerine, sul- 
phuric acid, and paranitro-anisol, &jid then reducing to the tetrahydro- 
compound. It is an oily liquid, easily frozen, and then only re-melts 
at 180°, with a strong odour like Tonka beans, and soluble in acids to 
form crystalline salts. Ferric chloride produces an intense greea 
colour, hence the name (da\}.6g, a green twig). 

The sulphate and tartrate are found in commerce as yellowish-white 
crystalline powders, soluble in about 7 and 10 parts of water, sparingly 
in alcohol. They are acid, fragrant, and bitter, and darken in light. 

In a paper by H. Schultz " On the InJBuence of Thalline Salts on 
Putrefaction and Fermentation,"* he states that "0*5 per cent, of 
thalline sulphate in sterilised gelatine prevented the further putre- 
faction of meat. Yeast fermentation was considerably retarded by 

1 per cent, of thalline tartrate ; with a less quantity, however, the 
activity was increased," probably by supplying nitrogenous food to the 
fungus. It must be observed that the agent would not answer for a 
food-preservative, on account of its taste, odour, and physiological 
action. Thalline was at first extolled as a substitute for quinine, 

2 to 8 grains of sulphate or tartrate being given in aqueous solution, 
but the salts are poisonous to the red blood corpuscles and act on the 
nerve centres (Brouardel). As antiseptics they are still occasionally 
used for injections (4 to 8 grains to the ounce) in gonorrhcea. 

Quinine, CgoHg^NgO^jSHgO, appears to be a derivative of a partially 
hydrogenised di-quinoline, and to have the formula 

C9H6(OCH3)N - 09Hji(OH)N.CH3, 

although it has not yet been synthesised. f Its action against fevers- 
is probably as much due to its antiseptic power as to its effect on the 
nervous system. The natives of Peru were in the habit of purifying 
the water of fetid pools by throwing in logs of cinchona (Humboldt), 
but the tannin would also take part in this treatment. Koch observes : 
"The dose of quinine necessary to destroy the spirilla of relapsing 
fever would be 12 to 16 grammes, which would kill the host as well 
as the parasite." A much less dose is sufficient to restrain the 

Antiseptol, iodo-sulphate of cinch onine, contains 50 per cent, of 
iodine, and is said by Yvon J to be a powerful antiseptic for surgical 
use. It must not be confounded with other antiseptics having a 
similar name. 

♦ Centr. Med. Wissensch., 1886, p. 113. 
+ Liebig's Annalen, vol. cciv., p. 90. 
+ Amer, Journ. of Pharm., Oct., 1890. 




Benzoic Acid : Its Use as an Antiseptic — Benzo-boracic Acid, &c. — Benzoic- 
Aldehyd, or Oil of Bitter Almonds — Sulpho-benzoic Acid — Benzosol — Benzo- 
paracresol and Benzo-naphthol. Salicylic Acid : Its Three Isomerides — 
Salicylates — Oil of Wintergreen — Salol — Salophen — Phenosalyl — Antiseptic 
Value of Salicylic Acid — Patents — " Lactacidine " — The Use of Salicylic Acid 
for Preserving Food — Objections — Tablets, Gauze, &c. — Anisic Acid — 
Cinnamic Acid, Styracol — /3-Phenyl Propionic Acid — Phenyl Acetic Acid — 
Gallic Acid — Tannin — Diphenj'l Derivatives — Styrone — Sodium Dithiosali- 
cylate. Thymol, Camphors, and Essential Oils : The Terpenes, their 
Properties and Products of Oxidation — Turpentines — Camphors — Thymol 
Aristol — Europhene — Menthol — Oil of Cloves, Caraway, Hops, &c. — Terebene, 
Oil of Eucalyptus — Camphor, Personal Use — Fatents—Eucalyptol — Eucalypto- 
resorcin — Myrtol — Terpin Hydrate —Terpinol — Absynthol — Cary ophyllin — 
Eugenol — Bomeol-^ Various Patents — Camphoid — Combining Disinfectants 
with Soda Crystals — Bases of Powders — The Oxidising Power of Essential 
Oils — Ozone Test — Sanitas, Sanitas Oil — Value of Sanit£is as a Disinfectant — 
Camphoric Acid — "Pinol." 


Benzoic Acid, CgH^ . CO . OH, exists in gum benzoin, balsams of 
Peru and Tolu, and several aromatic gums that have been used for 
ages for enbalming. It is made by acting on boiling toluene, 
CeH5(CH3), with chlorine, and oxidising the benzyl chloride, 
CgHg. CHoCl, with nitric acid. It melts at 121° C, boils at 250° C, 
but sublimes slowly with a pungent, aromatic odour, even at ordinary 
temperatures. It is sparingly soluble in cold water, yielding an acid 
solution of pungent, disagreeable taste. It acts as a stimulant, 
expectorant, diuretic, and is strongly antiseptic both as solid, solution, 
and vapour, and even in its salts. 

Salkowski,* in a number of experiments with meat juice inoculated 
with putrid fluid, showed that benzoic acid, in a dose smaller than 
salicylic, prevented for a long time the putrefaction of the mixture 
and the development of bacteria. Bucholtz t found that 1 in 1,000 
stopped the growth of micro-organisms. Haberkorn did not succeed 

* Ueher die antiaept. Wirkung d. Salicylmure und Benzoesdure, Berlin Klin. 
Wochemchr., 1875, p. 22. 
t Archiv.f. exp. Pathol., 1876, vol. iv. 


with the bacteria of urine with less than 1 in 400. Jalan de la 
Croix,* in seventy-four experiments with varying quantities, showed 
that the least quantity that would prevent bacterial growth from 
being inoculated into a fresh liquid (beef tea) was 1 in 2,800. To kill 
bacteria he required 1 in 410, and to sterilise spores 1 in 50. As 
regards non-organised ferments (" enzymes "), Wernitz f declares that 
pepsin is neutralised by 1 in 200, and others by 1 in 300, of benzoic 
acid or benzoate of soda. 

Graham Brown j stated that sodium benzoate was superior to 
quinine hydrochloride and sodium salicylate in destroying the virus 
of diphtheria ; he believed even that by saturating the liuman system 
with benzoic acid by repeated hypodermic injections, it was rendered 
almost insusceptible of inoculation with diphtheria. 

In disorders of the bladder, attended by ammoniacal urine, Gosselin 
and Robin § proved that benzoic acid taken internally rendered the 
urine acid, preventing the precipitation of insoluble phosphates, and 
the formation of carbonate of ammonium and poisonous salts by the 
urinary bacteria, and also diminished the amount of urea excreted. 
Therefore, Frerichs introduced it successfully for uraemia. They use 
1 to 4 grammes per day dissolved in glycerine and water. 

Vallin states || that " in most cases, to destroy definitely and 
without return germs transplanted from a sterilised liquid into the 
midst of an appropriate culture fluid, the proportion of benzoic acid 
should be 1 in 77, or even 1 in 50." This would make it rather more 
potent than phenol, cresol, or other similar compounds. It is not 
poisonous ; Prof Senator, of Berlin, gave as much as 50 grms. of 
sodium benzoate a day to a patient with acute rheumatism, without ill 
effect. As much as 1 oz. of ammonium benzoate per day can be taken 
without any noticeable effect, and is excreted as hippuric acid in 
the urine. 

In those cases in which the odour and taste is immaterial, a 
saturated solution of benzoic acid in water delays the putrefaction of 
animal matters much more effectively than salicylic. It has less 
effect on vegetable effusions. It is also useful for preventing fats 
from becoming rancid. Added to milk, a very small quantity 
prevents coagulation.lT 

Benzoic acid and benzoates are ingredients in many antiseptic 
mixtures, as, for example, the following complex receipt : — " Anti- 
septic pastilles for use in diphtheria are made by incorporating boric 

* Archiv. f. exp. Pathol,, 1881, vol. xiii., p. 175. 

+ Dorpat Essay, 1880. + Kleb's Archiv., vol. viii., p. 140. 

§ Arch. gerUrales de M6d., 1874, vol, xxiv., p. 566. || Disinfectants, p. 202. 
IT Horn, Zeitachr.f. Chem. Industr., vol. ii., p. 329, 1888. 


acid and borax, each 20 grms.; citric acid, 125 grms.; sodium benzoate, 
1 grm., with glycerine and water as solvents, and gum, sugar, and 
gelatine as bases, and dividing into 500 pastilles."* Dr. Miller states 
that by using the following mixture he could completely sterilise the 
mouth and cavities in carious teeth : — " Thymol 4 grains ; benzoic 
acid, 45 grains ; tincture of eucalyptus, 3| drachms ; water, 25 ozs." f 

By heating benzoic with boracic, tartaric, or citric acid, double com- 
pound acids called benzo- boracic, «fec., are formed, which are, of course, 
antiseptic, and are mentioned in some of the older patents. 

Although the benzoic acid is thus rendered much more soluble, and 
its taste is in great part disguised, it frequently crystallises out, and 
hence these compounds are now seldom heard of This separation also 
makes them irritant to wounds and mucous surfaces. 

Listerine contains 2 grains of benzo-boracic acid in each fluid drachm,, 
together with the essential oils of thyme, eucalyptus, BajHisia, Gaul- 
tlieria, and Mentha arvensis. 

Benzoic aldehyde, or benzaldehyd, CgHg. CO . H, occurs with hydro- 
cyanic acid in oil of bitter almonds. Angus Smith % considered it a 
little below phenol in antise{)tic power. It readily oxidises to benzoic 
acid, is sparingly soluble (1 in 30), and is of no hygienic use except in 
ointments, when the crude oil is very effective against eczema, irrita- 
tion, and parasites, partly on account of the prussic acid it contains. 
Obviously the skin must not be broken. 

Sulphobenzoic acids, C^H4(HS03)(CO.OH), of which there are three 
isomers, made by the action of oil of vitriol on benzoic acid, are very 
soluble, and have an acid and bitter taste. They and their salts are 
antiseptic.§ The derivative "Saccharin," benzoyl -sulphonicimide, is 
also sometimes used as a preservative. It has the constitution, 

c,h/ )nh. 

The mixture of sodium salts are met with as an antiseptic under the 
name of sodium sulphobenzoate.§ 

Benzanilide is a weak antiseptic used as an antifebrile. 

"Benzosol," or benzoyl-guaiacol, (CgH5)CO.O(OgH4.0CH3), is obtained 
Irom benzoyl chloride and sodium guaiacol. It is a crystalline powder, 
colourless, almost free from taste and smell, insoluble in water, easily 
soluble in alcohol, and melts at 50° C. It is said to combine the 
effects of guaiacol (p. 175) and benzoic acid without any disadvantages, 
and to be very useful in tuberculosis, facilitating expectoration and 

* Year-Book of Pharmacy, 1889. t Chem. and Drug., 1887, p. 83. 

t Disinfeclanta, Edinburgh, 1869. § Joum. Soc. Chem. hid., 1888, p. 226. 


rendering the sputum free from bacilli. Prof Sahli, however, remarks 
that the commercial article is of varying composition, that he found 
some specimens inert, and that "as the effect of guaiacol and creosote 
were due to local antiseptic action in the stomach, benzosol could not 
take their place." It is used largely in diabetes mellitus. 

Benzo-paracresol, CgH3(CgH5.CO)(CH3).OH, is an antiseptic prepared 
by the action of sodium benzoate on paracresol (p. 164), in presence of 
oxychloride of phosphorus. It occurs as a crystalline powder almost 
insoluble in water, but soluble in alcohol (0-15 per cent.). It melts 
at 71° C* 

Benzo-naphthol, C^oH;O.CO{CgH5), from /3-napthol, melts at 110° C, 
and has also been proposed for internal antisepsis. 


There are three isomeric oxybenzoic acids, of which only the ortho- 
compound, called salicylic acid, CgH4(0H).C00H, is of practical 
importance. It is met with in minute white needles or prisms, of 
pungent odour and sweet taste (inodorous when pure, Charteris), 
soluble in 500 parts of cold, and 15 of boiling water, in 7 of alcohol, 
3 of ether, and 50 of glycerine. When heated quickly it breaks up 
into phenol, which distils, and carbonic acid. The same decom- 
position occurs in the human system, as phenol appears in the urine. 
It is antiseptic and antipyretic. 

J. B. Duggan found that it was twice as powerful an antiseptic as 
the corresponding para-oxy-benzoic acid, whilst the meta-acid had 
intermediate properties,! 

" Artificial " salicylic acid (from sodium phenate and carbonic acid) 
is somewhat more toxic in its action than the pure " natural " acid 
obtained from oil of wintergreen. This is due to two foreign acids, 
isolated by Williams in 1878, and found by Dunstan and Blochj to be 
ortho- and meta-cresotic acids, CgH3(CH3)(OH).COOH, derived from 
the cresols contained in the crude phenol from which the salicylic 
acid had been prepared. Schering and others now prepare a pure 
artificial acid from pure phenol, which is free from these impurities, 
and acts in the same way as the natural acid. It melts at 156*7° C. 
It gives a purple colour with ferric salts, therefore cannot be pre- 
scribed with them. It is not corrosive, and does not coagulate 

The salicylates are much more soluble. Salts of nearly every metal 
have been prepared and recommended for various uses; but sodium 
salicylate, CgH^(OH).COONa, is the most usual one. 

* Eevue de Chim. Indtialr., April 15, 1893. t Am. Chem. Journ., vol, vii,, p. 62. 
i Journ. Chem. Soc, April, 1891. 


Oil of Wintergreen, GauUlieria procumhens, is methyl salicylate, 
OgH^(OH)COO(CH3). It is a colourless, fragrant liquid, sparingly 
soluble in water, but easily in alcohol, and also in alkalies. Specific 
gravity, 1-18 ; boiling point, 222° C. 

Perier, of the hospital of St. Antoine, Paris, substituted this oil 
for phenol in surgery, using a mixture which was perfectly miscible 
with water : — Oil of Wintergreen 30 grammes, tincture of quillaia 
6 grammes, water 1 litre. Gosselin and Bergeron* found that the oil, 
both as a solution and as vapour, hindered the putrefaction of blood, 
and that it was neither irritant, nor of disagreeable odour. It is still 
used in France for dressings, but is inferior to phenol and other agents 
in power. It does not coagulate albumen, and is not poisonous. 

"Salol," Phenyl salicylate, C!6H4(OH).COO(C6H5), is made from 
sodium phenol and sodium salicylate by heating with phosphorus 
oxychloride. It is a white crystalline powder, melting at 42° C, 
with a fiiint aromatic odour, practically tasteless, neutral, insoluble 
in cold water, soluble in 15 parts of rectified spirit, in 3 of ether, 
and very soluble in chloroform and in oils. Antipyretic and anti- 
septic, it passes through the stomach unchanged, to be decomposed 
in the duodenum into phenol and salicylic acid.f It is used in 
•diarrhoea, dysentery, cliolera, &c., as an internal antiseptic, also as 
an injection in gonorrhoea and cystitis. It has been employed 
externally as a substitute for iodoform in skin and nasal diseases. 
Lowenthal + has shown that salol will kill cholera bacilli in a paste 
■containing pancreatic juice. Spirituous solutions (5 per cent.) are 
employed with various flavouring agents for mouth-washes and 
•dentifrices, toilet-powders, and soaps. When melted with camphor, 
salol, like many other substances, forms a permanent liquid which 
has also been used to replace iodoform.§ 

"SalophcD," C^H^(OH)(COO.C6H^.NH.CO.CH3), an imido-com- 
pound formed by heating salicylic acid with phosphorus oxychloride 
and para-nitrophenol, reducing and acetylating, resembles the preceding 
in properties, but is said to have rather stronger antiseptic power. 
M. P. 188° 0. It has not been much used, and is expensive. 

Cresyl Salicylates. — The three cresols form corresponding salicylates, 
and have been proposed as internal antiseptics. 

Betol, salinaphthol, or naphthosalol, is a j3-naphthol salicylate, and 
has already been described under Napthol (p. 179). 

Salbromanilide is said to be a mixture of bromacetanilide and sali- 

Salipyrin is a compound of antipyrin and salicylic acid. 

* Arch, general, dt 2Idd., 1881, p. 16. + Brit. Med. Journ., 1887, vol. xi, p. 1438. 
J Complea Bendus, vol. cvii., p. 1169. § Repertoire, 1889, p. 185. 


Phenosalyl is a mixture of phenol, salicylic, benzoic, and lactic acidf, 
made by heating them together at 140° C, adding menthol and euca- 
lyptol, and, after, cooling, adding four times the volume of glycerine. 
It is a clear, syrupy liquid, of sweetish taste. It is easily miscible 
with water or alcohol, is not poisonous, and has a pleasant and non- 
persistent odour, which does not cling about the hands and clothes. 
The solutions have no corrosive action on the skin, the mucous sur- 
faces remain smooth and slippery, and do not become dried up, as is 
the case after washing with carbolic acid or "corrosive sublimate." 
Of course, this latter advantage belongs to the glycerine, and would 
equally pertain to phenol or mercuric chloride in the same medium. 

Prof. Frankel,* in a series of bacteriological trials, found that pheno- 
salyl possessed an antiseptic power superior to phenol in dealing with 
the micro-organisms of cholera, anthrax, pneumonia, typhus, diph- 
theria, tuberculosis. Bacillus pyocyaneus, and Staphylococcus pyogenes 
aureus. " It is well known that the last-mentioned bacterium is one 
of the most resistant, but even a 1 per cent, solution of phenosalyl is 
sufficient to kill it, while to produce the same effect with carbolic acid 
one must use a 2| per cent, strength, and the exposure or contact 
must be continued for a longer period." Phenosalyl has been used by 
Duloroy in the sterilisation of instruments, of gauze, antl of different 
organic substances like blood, as well as decomposing urine and the 
saliva of consumptives with most encouraging results. It does not 
corrode nor discolour metals under ordinary circumstances of contact. 

This is an example of a mixture which seems to present great 
advantages. Of late years there has been a tendency to use compli- 
cated compounds, most of them only soluble in alcohol, which, apart 
from expense and other faults, is inadmissible as a medium for many 
purposes. It should be noticed that while in mixtures the properties 
of the ingredients are mostly retained, in many of these compounds 
not only are the properties lost, but frequently new and objectionable 
ones are developed. For example, the desire to avoid the unpleasant 
odour of iodoform has led to the introduction of many " substitutes " 
which are costly, unstable, uncertain, and even dangerous in their 

However, phenosalyl may be reckoned as a convenient preparation 
of the above aromatic acids dissolved in lactic acid and glycerine, and 
scented with menthol and eucalyptus. The name is rather an unfor- 
tunate one, as leading to a wrong idea of its composition. 

Salicylic acid is by no means an innocent remedy. In fact it can 
be a powerful poison, as it has a disintegrating action on the blood 
corpuscles. The salts cause albuminuria, hence, must be irritating 
* Baeterienkunde, Berlin, 1890. 


to the kidneys, probably througli phenol being formed.* The acid, 
in strong (alcoholic) solutions, or in ointments, is so caustic that it 
is the basis of most of the popular cures for corns. t As to dilute 
solutions, Dr. Bond, of Westminster Hospital, states that "when in 
the country he has been in the habit of taking 10 grains daily for a 
month without bad effect," obviously as an anti-iualarial. The official 
dose of the acid is 5 to 30 grains. Dr. Brouardel has noticed daily 
doses of 2 grammes to produce grave symptoms of intoxication and 
poisoning. KolbeJ first drew attention to the antiseptic properties 
of salicylic acid. He showed that it prevented the action of enzymes 
(unorganised ferments), like diastase, emulsin, and that of mustard, 
also gastric digestion, fermentation by yeast, ammoniacal fermentation 
of urine, and the germination of heeds. H. A. Weber § and Leffman 
and Beam || proved that a solution of 1 in 420 of salicylic acid, com- 
pletely checked salivary and pancreatic digestion of starch, and that 
even 1 in 840 had a marked depressing influence. 

As to the strength required for killing bacteria, it has been 
variously given by different observers. Ratimoff^ uses 1 in 400, 
practically a saturated solution in water and a little spirit; Jalan 
de la Croix,** 1 in 200 for milk, and more than 1 in 35 for germs 
in meat juice ; Buchbltz,tt 1 in 362 ; and Kiihn, 1 in 200 for germs in 
albumen solution. As to salicylate of soda, the necessary dose is 
stated as 1 in 100 by Miquel, and 1 in 161 by Bucholtz. 

Vallin II points out that "this action on ferments and microbes is 
often only temporary ; the ferments and bacteria rapidly become used 
to their new surroundings, and the generations that succeed resist 
doses that had been fatal to their ancestors, and the work of fermenta- 
tion goes on again at the end of a few days. Keubaur and Bechamp 
have specially proved this curious phenomenon of the habituation of 
ferments to progressive doses of phenol and salicylic acid. It follows, 
that, to obtain a durable antiseptic effect, we must at frequent inter- 
vals add new and increasing doses of the agent. For this reason, in 
alcoholic beverages, which can only be preserved by the aid of salicylic 
acid, the dose of this substance sometimes reaches as much as 1*5 
grammes per litre. Even then experience has shown that poor wines 
and ciders soon undergo fresh fermentation of acid or putrid character. 

* See a paper by Dr. Squire on the " Physiology and Therapeutics of Salicylic 
Acid," Lancet, Dec. 20, 1879. 

t Whelpley, Chem. and Drug., Aug. 16, 1890. 

+ J.Jur Pract. Chem., 1874, vol. x., p. 89. 

§ Journ. of Amer. Chem. Soc, 1892, p. 4. 

II Journ. Soc. Chem. Ind., 1888, p. 582. 

IT Bied. CeutrcUblatt, vol. xiv., p. 360. ** Ardi. exp. Pathol., 1881. 

tt Ibid., 1875. tX D4nn/cctinU, p. 182. 


Salicylic acid, then, is a convenient antiseptic, but it gives no absolute 
guarantee, and its power is limited.j' 

The very sparing solubility of salicylic acid in water has led to a 
variety of devices for increasing it. Alcohol is in many cases unsuit- 
able ; glycerine only dissolves 2 per cent.; alkalies form salicylates, 
■which, although soluble, have only about one-third the antiseptic 
power of the free acid. Borax solution dissolves a large quantity of 
salicylic acid, forming a loosely-combined crystalline compound, in- 
odorous, neutral, and of little taste, called borosalicylate of soda. It 
is much more soluble, and is more antiseptic than either of its com- 
ponents (see under Boric Acid, p. 102). 

OfFen and Moore,* " to prevent the second fermentation of yeast or 
•other ferment when combined with wheat or other cereal for food," 
use 10 parts of salicylic acid, 3 of box'ic, and 4 of borax, dissolved and 
mixed with the grain either whole or ground ; " yeast is then added, 
And the dough baked as usual." 

Lactacidine solution contains 2*65 per cent, lactic acid, and 0-35 per 
•cent, salicylic acid, " to which other materials, such as sugar or 
glycerine, may be added." It is used for preserving articles of food — 
€.g., butter. It may be removed by washing before use.t 

Salicylic acid is largely used for preventing loss of material, and 
•consequent annoyance with fruit; 4 to 8 grains of the acid to the 
pint or lb. prevent fermentation in saccharine liquids; and jams, 
preserves, &c., can be kept for years. " As a preservative it is best 
applied in process of preparation. It is advisable to gradually intro- 
•duce it in the solid state into the boiling mass "(but it somewhat 
readily volatilises with the vapour of water), "constantly stirring, 
or the acid may be rubbed down with the fruit juice, and then added. 
In any case the finished product ought not to show any white flocks." 
Another mode is to pour over the cold uncooked fruit the cold 
isalicylated juice of the same fruit, so that the fruit is entirely 
covered. A cold juice may be made by pressing the fruit, adding 
to every pound 15 grains of the acid, heating the juice, and allowing 
to cooL In this way, cherries, plums, &c., can be preserved all the 
winter uncooked, and are then suitable for pies. The last of the 
above processes seems better than the others, since almost all the 
salicylic acid can be removed by washing the fruit before cooking. 

Salicylic acid is very largely used for perishable articles of food. 
Many preparations, more particularly of salicylic and boric acids, are 
sold as *' lard bleachers," and " fruit, wine, and cider preservatives." 
Most authorities agree that it is a most objectionable preservative, 
especially in milk which is destined for young children. Powdered 
♦ Patent No. 16,592, 1887. t Orosjils, Patent No. 2,235, 1887. 


salicylic acid, that has been used for hams, fish, &c., is mostly washed 
off, but when mixed with, or allowed to penetrate the food, chronic 
dyspepsia and other symptoms would certainly be caused by the rela- 
tively large quantities that would accumulate in the system. There 
seems evidence to show that, like lead and arsenic, it has a cumulative 
action. Vallin,* in an exhaustive discussion of this point, shows that 
if a man consumes an average quantity of salicylated foods and drinks 
as met with in France (he gives tables of the amount customarily 
added to a number of foods) he would absorb per day 3 grammes of 
salicylic acid. He observes that it is nefariously used to secure the 
disposal of inferior articles that would not otherwise be saleable. In 
1880 the French Committee of Public Hygiene, after the matter had 
been fully reported upon by M. Dubrisay, passed, on Feb. 7, 1881, the 
following edict which is still in force : — 

" Ust interdite la vente de toute substance alimentaire, liquide ou 
solide, contenant une quantite qudconque d'acide scdicylique ou d'un de 
ses derives." 

At the present day, food arriving at the city barriers, if it should 
be adulterated, and especially with salicylic acid, is seized, and its 
owner punished. 

K. Portele says j that salicylic acid cannot be considered a success 
as a preservative either for butter or milk, as it gives to them an 
unpleasant sweetish odour, which increases until decomposition takes 

H. A. Weber J and Dr. H. Yogel § strongly condemn the practice 
of adding preservatives to food, proving that it interferes with 
digestion. Nessler observes that "salicylic acid is not a natural 
constituent of any food, and its addition is a fraud on the quality." 
He, with Vogel, Pasteur, and others, demanded that the addition 
of any quantity of this acid to wine should be mentioned on the bottle. 
The German Government seem to be yet undecided. 

In England, although a few trifling increases of fine have followed 
the finding of salicylic acid by public analysts in milk where there was 
added water also, it seems to be recognised as a customary addition to 
syrups and to "British wines." In a test case at the Great Marlow 
Petty Sessions, a grocer was prosecuted for selling raspberry wine 
adulterated with salicylic acid. For the defence two analysts swore 
that salicylic acid " was absolutely necessary to preserve the wine," 
and that it was "quite innocuous." In the result the case was dis- 

• DdsinfeclarUs, pp. 189 to 193. 
t Landw. Versucha. Slat., vol. xxviL, p. 143. 
XJoum. Amer. Chem. Soc, vol. xiv., pp. 4-14. 
§ Deutsche Viert.f. (iff. Gea., 1880, p. 40-2, 


missed. If wines be Ccarefully made, they can be sterilised without 
any drug, and will keep for a reasoijable time after opening. 

Among special salicylic acid pre])arations the following may be 
noticed : — 

Solution for Local Antisepsis.* — Water, 1,000; boric acid, 12; sali- 
cylic acid, 2. 

In Patent No. 15,564, 1887, Boake and others show that "sodium 
sulphite dissolves one-sixth of its weight of salicylic acid ;" they pro- 
pose to make such solutions with any^alkaline sulphites or bisulphites 
for antiseptic purposes. 

"Stroch's Antiseptic Paper." — Seep. 142, 

Antiseptic Tablets. — " (1) For Thiersch's solution, much used in 
many modern operations, Adolph Levy, of Brooklyn, N.Y., recommends 
14 grains of ' resublimed ' salicylic acid and 84 grains of pure boric 
acid, to be compressed into a tablet, which is dissolved when required 
in 16 ounces of hot distilled water, f (2) Warner it Co. make pastilles 
of sodium bicarbonate, biborate, benzoate, and salicylate, with menthol, 
eucalyptol, and oil of wintergreen. One of the pastilles gives 2 ounces 
of a solution to be applied as spray in nasal catarrh." " Strongly 
deodorant as well as antiseptic." :j: (3) Sacker, 79 Fenchurch Street, 
make tablets of similar composition, " to be each dissolved in two 
quarts of water." § 

Salicylated Gauze. — Gauze washed with soda to remove grease, then 
in succession with water and acidulated water, then bleached by 
chloride of lime and weak acid, and finally well washed with water 
and dried. Next soaked in a solution of salicylic acid, 5-6 parts; 
glycerine, 15; rectified spirit, 50; distilled water up to 100 parts; 
drained, nearly dried by a current of sterilised warm air, rolled or 
folded by machines previously made aseptic. The finished gauze is 
packed in cylinders freshly lined with melted paraffin sterilised by 
heat. The gauze is thus kept permanently slightly moist. || Contact 
with iron must be avoided, or purple stains result. 

Anisic Acid or para-oxymethyl-benzoic, C^H4(0CH.;)C00H, occurs 
in colourless prisms, melting at 175° and distilling at 280° C. The 
sodium salt was recommended by Curci in 1887 as antiseptic and 
antipyretic, in doses of 15 grains. It was said to be analogous in 
action to sodium salicylate, but without disturbing influence on 

Cinnamic Acid, C^-IIyCH :CH.COOH, also met with in prisms, is 

* Carcano and Cesares, lievue de Chim. Indust,, April 15, 1893. 

t Chem. and Drug., vol. xxxviii., 1891. 

J Lancet, vol. xi., 1890. § Lancet, vol. xi., 1889, p. 174. 

II Seward Williams, Chem. and Drug., May 27, 1893. 


more soluble ; melts at 133°, boils at 290° C. It is somewhat strongly- 

Styracol or cinnamyl - guaiacol, O^Hs.CH : CH.COO(C^H4.0CH3), 
occurs in needle crystals ; is said to be a strong antiseptic in catarrh 
of the bladder and intestines, and in phthisis ; soluble in alcohol.* 

/3-Phenyl-propionic Acid or hydrociunamic acid, C,iH5.CHo.CH2.COOH, 
is formed in the decay of albuminous matter, and, like other similar 
products, is a bactericide. It forms fine needles, moderately soluble, 
melting at 47° and boiling at 280° C. Klein regards this and phenyl- 
acetic acid, CqH,;.0H2,C00H (sparingly soluble pearly plates, melting 
at 76°, boiling at 262°, strong odour of burning urine), as among the 
strongest of disinfectants. Laws has studied the next acid in this 
series (see p. 159). 

Gallic Acid, trioxybenzoic, OgH2(OH)3,COOH, is astringent and 
feebly antiseptic. It occurs in sparingly soluble inodorous needles. 

Taimin, gallotannic acid, Cj^HjqO(),2H20, is an amorphous powder, 
usually brownish, very soluble, and strongly astringent. It is well 
known to precipitate gelatin, and to form a compound with skins which 
is imputrescible (leather). It also coagulates albumen. Therefore it 
is, in some sense, antiseptic, but Gosselin and Bergeron,t having added 
to 2 grammes of fresh blood 8 drops of a 10 per cent, aqueous solution 
of tannin, saw vibrios appear in the mixture on the fourth or fifth day — 
that is to say, almost as soon as they would without any antiseptic. 
Gubler and Bordier | state that a horse which for many days had 
received doses of 20 grammes of tannin, remained with its blood un- 
putrefied till the fifth day after death. 

There are many varieties of tannins from many diflferent plants, but 
none of them have even the power to preserve their own solutions. 

Styrone forms silky white crystals of a sweet taste, and having an 
odour like hyacinths. It is soluble in 12 parts of water, and easily 
in alcohol. The saturated aqueous solution has been recently found 
in America to be a perfect deodoriser of a foul ulcerated surface, and 
to cause no irritation. As an antiseptic it is said to exceed thymol. 
This explains the healing properties long attributed to tincture of 
benzoin, of which liquid storax is a constituent. 


Sodium Dithiosalicylate "No. 1," | .has only re- 

cently been brought under notice as a powerful antiseptic. In a 15 
per cent, solution the most resistant bacilli are easily destroyed in 
from twelve to fifteen minutes. In a severe case of ozoena it efi*ected 

• A. Haas, Sudd. Apoth. Zeit., 1891, p. 55. t Arch, de M^d., 1881, p. 16. 
t Bull, de T/UrapeuL, 1873, vol. Ixxxiv., p. 265. 


a complete cure in a relatively short time. In 2| to 5 per cent, solu- 
tion this preparation is reported to have yielded most strikingly 
beneficial results in the treatment of foot-and-mouth disease, in which 
its further trial would seem to be very desirable.* 


From the time of the ancients it has been known that this class of 
aromatic bodies had a prophylactic action against fevers, and were of 
value in purifying air, and as insecticides. Precious woods were those 
which contained essential oils, like sandal- wood and cedar ; they were 
used in constructions wished to be imperishable, and for boxes to 
contain valuable tissues and documents. They were burnt for fumiga- 
tions to drive away diseases, they were carried about the person, they 
were thrown as logs into water, and mixed in wines and possets. The 
ancient classic wines had generally a strong resinous flavour, due to 
the admixture of herbs, and even to a trace of wood-tar purposely 
added to the grapes to check objectionable fermentation, also to 
bitumen on the stoppers, so that, apart from the agreeable odour, 
there was also a real sanitary use for perfumes. A large number of 
patents for disinfection contain aromatic gums and resins as adjuncts. 
It is well known that these were used with bitumen for embalming, 
and bodies have been preserved in this way. The result, however, 
was in great part due to desiccation and protection from the air. 

Musk, which seemed to give some relief in plague cases at Hong 
Kong, has been successfully used in large doses for cholera by 

These odorous principles are divided into two classes : — 

Class I. — Hydrocarbons, composed of carbon and hydrogen "only. 
They mostly belong to the terpene groiip, CjqHjq, or derivatives of it. 
This formula includes the liquid portions of the oils of thyme, orange, 
lemon, savine, turpentine, juniper, hop, cloves, camomile, and the 
majority of others. It will be noticed that the use of condiments may 
be explained on the assumption that they are all (including salt, 
mustard, and vinegar) antiseptic and preventive of fermentation, 
hence germs in the alimentary canal have their action arrested. Oils 
of capivi and cubebs, probably affecting micro-organisms in the urinary 
tract, have the polymeric formula, CJ5H24, as proved by their vapour 
density. Cedrene, from cedar, is said to be Cj^jHgQ, hence would not 
be a terpene. Menthene from peppermint is C^oH^g. The cause of 
the differences in odour of these different compounds of the same 
formula is not yet entirely known, but in many cases the difference 
is due to physical isomerism. All are liquids with boiling points much 

•Helbing, Med. Materia Medica, p. 90. i Prov. Med. Journ., Feb., 1S94. 


higher than that of -water (mostly 160° to 180° C), yet they emit at 
ordinary temperature minute quantities of strongly scented vapour^ 
and are readily volatilised with steam. Their specific gravity is 
usually less than that of water (0"83, orange, to 0*94, caraway), and 
they are almost insoluble in it ; they are readily soluble in alcohol^ 
forming " essences," and in other hydrocarbons and in fatty oils. 
When fragrant plants are distilled with water the essential oils float 
on the surface of the distillate, while a small proportion dissolves to- 
form the "distilled waters" of pharmacy, all of which are mildly 

Both the essential and the fatty oils produce a greasy spot on paper^ 
but the spot produced by the former gradually disappears, whereas- 
that of the latter remains fixed, so that the presence of adulteration 
can be easily detected. 

The essential oils neither combine with, nor dissolve in, alkalies ;. 
yet, if they be present when resins or fat are saponified, a large propor- 
tion remains dissolved in the soap, and is only liberated on dilution 
with water, when an emulsion similar to those obtained with tar 
oils is formed. 

Chlorine, bromine, and iodine act on most of the essential oils, 
(iodine at first merely dissolves), giving compounds in which the 
halogen displaces one or more atoms of hydrogen, at the same time 
the odour is much afiected, becoming gradually pungent. Excess of 
chlorine breaks them up entirely into hydrochloric acid and carbon. 
Therefore they are not suitable for use with the halogens. The 
antiseptic or disinfectant properties of substituted essential oils are 
not well known, but there is no evidence to indicate their utility. 

The terpenes rapidly absorb dry hydrochloric acid gas, yielding 
compounds called artificial camphors ; some of them are crystalline, 
and in appearance and properties much resemble natural camphors. 
Patents have been taken out for these products, but they have not 
hitherto been of much value. The artificial camphor obtained from 
oil of turpentine is the best known. 

Artificial camphors are only formed from the terpenes by slow 
combination with water. 

Turpentines. — When an incision is made in a pine tree, a resinous 
fluid flows out, which is mainly a solution of various resins in the 
hydrocarbon, O^qH^q, called "oil or essence of turpentine." " Common 
turpentine " comes chiefly from Finns ahies, " Venice turpentine " 
and " Bordeaux turpentine " from Pinus maritima, and " Chian 
turpentine" from Pistacia lentiscus. They are somewhat different 
in antiseptic value, but different specimens vary among themselves. 

By distillation with water, about one-fourth (the essence) passes 


over with the steam, while three-fourths remain behind as rosin. 
The latter has no antiseptic power, but is used as an adjunct or 
medium in a large number of organic disinfectants (J eyes, &c.). 

"Camphine" is the oil of turpentine from Finns australis. Letheby 
found that 1 in 4,000 of oil of turpentine in air prevented necrosis. 

Class II. — Oxidised Compounds, such as camphor, thymol, ikc, are 
crystalline solids, existing dissolved in the natural oil, from which 
they either separate spontaneously or by refrigeration. They were 
formerly called stearoptenes. Some of them have been formed by 
oxidation of the hydrocarbons, others are of a different constitution, 
such as — 

Thymol, propyl-m ethyl-phenol, or propyl-metacresol, CgH3(CH3) 
(C3lI-)0H. By cooling oil of thyme, crystals of thymol separate, 
while the liqiaid portion consists of thymene, CjoH^g, boiling at 
165° C. Oil of thyme contains about equal proportions of thymol 
and thymene ; both have the pleasant odour of the plant and a hot 
aromatic taste. 

Thymol is easily fusible (melting point, 44° C), lighter than water, 
in which it is very sparingly soluble (3 parts in 1,000), and is easily 
soluble in alcohol. It does not readily combine with, or dissolve in, 
alkalies, and is insoluble in acids, except sulphuric, with which it 
unites to form thymolsulphonic acid, in almost inodorous soluble 
crystals whose physiological properties do not seem to have been 

Dr. Paquet first* recommended thymol as an antiseptic in surgical 
dressings, and as an inhalation in pulmonary gangrene. Jalan de la 
Croix t found on an average that while 1 in 1,000 prevented bacteria 
from growing, 1 in 100 was necessary to kill them, and as much as 
1 in 20 to destroy the germs. Miquel ranks it as strongly antiseptic, 
since 2 grammes " neutralised " a litre of beef tea. Other observers 
found the following strengths necessary to prevent the development of 
bacteria ; in urine, 1 in 3,000 (Haberkorn) ; in infusion of peas, 1 in 
3,027 (Kuhn) ; in tobacco infusion, 1 in 2,000 (Bucholtz). Wernitz 
states that a saturated aqueous solution (3 in 1,000) arrests pancreatic 
digestion. Kobert, Kohler, and Stern used it to preserve vaccine 
lymph, as while it prevented it from putrefying, it only slightly 
diminished its activity. Koch mentions it as specially inhibitory to 
tubercle. EatimoffJ puts it fourth in his list of disinfectants, 
arranged in order of potency (mercuric chloride, silver nitrate, iodine, 
thymol), saying that " 1 in 35,000 killed putrefactive bacteria." 

* Bull, gin^ral de Th^rapeutique, 1868. 

+ Archiv.f. experim. Pathol., Jan. 20, 1881. 

t Bierdermann'a Cenlralblatt, vol. xiv., p. 360. 


Thymol in a saturated solution in water arrests fermentation and 
putrefaction better than carbolic or salicylic acids.* Thymol gauze is 
used in surgery, and an ointment has been made with lanoline. It is, 
however, too expensive for use on the large scale. 

" Listerine " is a mixture of the essential oils of thyme, eucalyptus, 
Baptisia, Gatdtheria, and Mentha arvensis ; each fluid drachm also 
contains 2 grains of refined and purified benzo-boracic acid. 

The action of iodine on thymol is of interest. The action may be 

represented as follows : — 

2C6H3(CH8)(C3H7)OH + SIj = + 4HI 


This compound is di-iodo-di-thymol, and is known commercially as 

Aristol or Annidaliae. — It is a white solid, melting at 60° C, insoluble 
in water, soluble easily in alcohol and ether. Like most iodine com- 
pounds it turns brown on exposure to light and air, liberating iodine. 
It is said to be strongly antiseptic. 

Menthol — Oil of peppermint contains a hydrocarbon, menthene, 
CjoHjg, boiling at 163° C, together with a white crystalline solid 
obtained by cooling it, menthol, C^QH^gHgO. Menthol melts at 34° C, 
and boils at 213° C. It smells of peppermint, and has antiseptic 

Peppermint from very early ages has had an immense repute as an 
arrester of fermentations. Several medical receipts for " plague water " 
have peppermint as a basis. In a recent cholera scare there was a 
strong demand both in Germany and England for peppermint herb, 
and for the oil and water. W. L. Braddon f directs attention to the 
antiseptic properties of oil of peppermint in diseases in which antisepsis 
is the best mode of treatment. Angus Smith spoke highly of it.:}: 

It was ascertained by Koch that 1 part of the oil in 300,000 arrested 
the development of spores, and that the vapour from warm oil of 
peppermint quickly killed both spores and bacilli. Dr. A. Macdonald 
found that the power of menthol is about double that of phenol — 
*' 1 in 500 kills bacteria." § Both it and oil of thyme seem to be useful 

Oil of Cloves. — This is extensively used for preserving paste, gum, 
•kc, and for carious teeth ("Bunter's Nervine"). It is heavier than 
most essential oils (specific gravity 0"918), rather more soluble in 
water, and n»ore volatile (boiling point 143° C). All these peculi- 
arities increase its value as an antiseptic. It consists chiefly of a 
liquid terpene, CjQHjg, holding in solution eugenic acid, CjqHjjOj 

* Brit. Med. Journ., 1875, vol. i., p. 680. t Year- Book of Pharmaq/, 1888. 
::: Disin/ectanU and Dmn/ection, 1869. § Edin, Med. Journ., 1880. p. 121. 



{Ettling), with an isomer eugenin, and a variety of camphor called 
caryophyllin, CioHjgO. 

(HI of Caraway is yet heavier (specific gravity 0*938). It contains a 
hydrocarbon carvene, CjoHig, isomeric with thymol — specific gravity 
0*953, boiling point 225° 0. (Voelcker). The latter yields with an 
alkaline solution of ammonium sulphide a peculiar substance named 
carvol hydrosulphide, (OjoHi40)2H2S, in yellowish crystals sparingly 
soluble in alcohol, almost insoluble in water, but slowly decomposed 
by it. It has an unpleasant odour, and is strongly antiseptic, but 
hardly available on account of cost, insolubility, and poisonous char- 
acter. Jalan de la Croix * states that 1 in 1,000 of carvol destroyed 
the bacteria of tobacco infusion, while 1 in 360 was requii'ed for those 
of urine. 

Oil of Cinnamon is considered by Lucas Championniere to be 
superior to even corrosive sublimate as an antiseptic. Oils of verbena 
and geranium have similar properties.t 

Essence of Hops is a powerful agent in checking fermentation, 
hence its former universal use in brewing. It readily absorbs oxygen, 
being converted into an acid resinous mass containing valerianic acid, 
CjHj^.COOH. The main constituents are a terpene, CjqHjq, and 
valerol, CgHjoO. 

All the other essential oils are more or less antiseptic, but their 
general use is negatived by (1) their cost; (2) sparing solubility;. 

(3) their persistent odour, which becomes after a time insupportable ; 

(4) their want of energy in terminating, as distinguished from re- 
straining, putrefaction and fermentation changes ; (5) internally, their 
injurious action on digestion. Their chief value, beyond that due to 
their odours and flavours, consists in their general property of hinder- 
ing fermentation in the alimentary canal. They are largely used 
for mouth washes, tooth powders, &c. 

Terebene, CjoHjg (specific gravity, 0-86; boiling point, 160° C), is a 
liquid obtained by acting on turpentine with about one-twentieth of 
its weight of oil of vitriol, and distilling. It has a strong odour re- 
sembling that of thyme and pine- wood, oxidises Jess readily than 
turpentine, and is only slightly soluble in water, but easily in alcohol 
and oils. Some years ago it was extensively commended as a " disin- 
fectant;" it has now almost fallen out of use except in "Terebene 
Soap," which is a pleasant preparation of some antiseptic power, con- 
taining 1 to 2 per cent, of terebene. 

Prof. Maclean, of Netley, reported favourably on its use for surgical 
and sanitary purposes. 

Camphors. — These are oxidised essential oils. 
♦ Archiv.f. exp. Pathol., Jan. 20, 1881. t liev. Thdrap., 1S93, p. 290. 


Ordinary or Laurel Camphor, CioH^gO, is a white solid of specific 
gravity -996. About 1 per cent, dissolves in water, communicating to 
it, as " camphor water," its odour, Avith its stimulant and antiseptic 
properties. It is very soluble in alcohol ; the tincture in moderate 
doses is an irritant poison. Dr. Kubini in Naples used it largely in 
cholera and diarrhoea. 

Camphor has some repute as a personal prophylactic, but it is obvious 
that there cannot be sufficient of the vapour to disinfect the air. It is 
irritant to the skin. It burns with a luminous sooty flame ; but when 
burnt, either alone or with spirit, the products of combustion contain 
little or no camphor. Spirit lamps containing this and essential 
oils in spirit have often been proposed for fumigation, but are 
obviously of little value. 

There are numerous inventions relating to camphor. " Sanoscent " 
is a block disinfectant containing camphor, eucalyptus, pine-oil, " and 
other germ-killers." The basis of most of the cakes or blocks commonly 
met with is either naphthalene, paraffin, or plaster. " Hebden's Cam- 
phortar" is camphor, eucalyptus, and tar distillates, similarly made 
into blocks for lavatories, &c., and also recommended to be gra,ted 
among clothes for insects (see under Naphiludene, p. 148). 

A mixture of equal parts of camphor and animal (vegetable?) 
charcoal is recommended by Barbocci for preventing the offensive odour 
and removing the pain (T) of old excavated ulcers.* 

Kylet has shown that camphor combines in molecular proportions 
with menthol. Symes % has made a similar compound with menthol. 
These compounds, like that with phenol, are generally liquids. Hille§ 
suggests its use with magnesium or calcium chloride for drains and 
for dressing vines. 

Bromo- and iodo-camphor are strongly antiseptic, but irritant. 

Eucalyptol, or eucalyptus camphor, O^QHjgO, was first isolated by 
E. Jahns from the essential oil of various species of Eucalyptus. 
Since then it has been detected in numerous other oils. Besides six 
species of Eucalyptus there are 15 plants which yield it. It is a 
colourless liquid, smelling like camphor, of specific gravity 0-930, 
boiling point 176° C, and crystallising point — 1° 0. It is practically 
insoluble in water, but is miscible with alcohol, ether, chloroform, and 
fatty oils. The Eiccalyptus trees have long been famous for their 
anti-malarial action, and are largely planted on the Continent in 
marshy districts. According to Cloez, the half-dried leaves contain 
€ per cent, of the oil. It is used in the antiseptic treatment of atonic 

• Clien. and Drug., 1887, p. 373. i Am. Journ. Pharm., 1885, p. 429. 

J Pharm. Journ., 3, vol. ix p. 598. § Patent No. 6,411, 1889. 


ulcers, gangrene, (fee, internally and by inhalation for pulmonary 

Candles containing 5 to 10 per cent, of oil of eucalyptus or cajeput 
with or without a little phenol were patented by "Wright. f In all 
these fumigating appliances the greater part of the organic matter 
is destroyed in burning, only a fraction being volatilised unchanged, 
■while the peculiar odour becomes after a time sickly and insupport- 
able. All fumigating candles, except the so-called "sulphur candles" 
(p. 93) and some bromine and iodine forms (p. 73), are therefore 
unsatisfactory. Tablets containing eucalyptus oil and chalk, which 
have a powerful and pleasant odour, have been introduced for domestic 
use. J 

Eucalypto-resorcin is a hard amorphous mass obtained by mixing 
eucalyptol with excess of resorcin in the cold. It crystallises from 
chloroform, is insoluble in water, but very soluble in alcohol and in 
ether. It is said to have some advantages as an antiseptic. 

Myrtol, from essence of myrtle, is a clear liquid of pleasant odour, 
boiling between 160° and 180° C. Eichorst recommended it as an 
internal antiseptic. It is a mixture of dextro-pinene (the main hydro- 
carbon of turpentine, juniper, eucalyptus, and sage oils, &c.) with 
eucalyptol, and would be advisedly replaced by the latter (Jahns). 

Terpin Hydrate, C^oHig(OH)o,H20, is prepared by the interaction of 
a mixture of 4 parts of oil of turpentine, 3 parts rectified spirit, and 
1 part of nitric acid in shallow porcelain dishes during some days. It 
occurs in large colourless and inodorous crystals with a faint aromatic 
taste. On warming there is a separation of the water and formation 
of terpin, CjoHi8(OH)2. The development of tubercle bacilli is arrested 
by a 0"25 per cent, solution (Colpi). It has been used internally in 
lung and kidney diseases (^Manasse and Talamon). 

" Terpineol " is the product obtained by boiling terpin or terpin 
hydrate with dilute mineral acids. According to Wallach it is a 
mixture in variable proportions of terpineol (CjoHjgO) and several 
terpenes. Guelpa and Morra have proposed it as an antiseptic in 
■cases of bronchitis. 

Absynthol is an isomer of camphor from oil of wormwood. 

Caryophyllin, CgoHg^Oo, is a polymer from oil of cloves ; Eugenol, 
CjqHjjOo, an unsaturated compound, being the chief constituent of 
the oil. 

Bomeol or Borneo camphor, CjqHjjjO, from Dryohalanopa campliora, 

* See Gimbertj Eucalyptus globulus, and its Importance in Agriculture, Hygiene, 
and Medicine (Paris, Delahaye, 1870). Demarquay in 1872 recommended euca- 
lyptol in surgery. Sir J. Lister has used it as a substitute for carbolic acid. 

t Patent No. 11,963, 1884. X Lancet, vol. xi, 1890, p. 724. 


is a white crystalline solid with an odour like pepper, resembling 
ordinary camphor in properties. It is slightly more antiseptic than 
camphor (Selmi). 

An "Improved Disinfecting Fluid"* consists of 28 lbs. chloride of 
lime, 14 lbs. of camphor, and 50 gallons of " black varnish" (a coal-tar 
product) mixed together. "After standing for eight days the resulting 
substance is ready for use in urinals, &c." 

Camphoid, though in itself only feebly antiseptic, is a useful vehicle 
for applying more active agents to the skin, and forms a protective 
coating. It is a mixture of camphor, pyroxylin, and alcohol. Several 
so-called disinfectant washing powders have been patented. These 
usually consist of a mixture of disinfectants with soda crystals. R. P. 
Hicks t makes a saturated solution of sodium carbonate in boiling 
water, and then on cooling, as it crystallises, a mixture of diamylene 
(or decylene, CjoHgo), cam])hene (one of the terpenes, C^oH^g), raenthene, 
terebene, cymol, thymol, and sometimes phenol is added. 

Many of the essential oils are used as disinfecting powders. Under 
phenol (p. 154) the bases of the most common powders have already 
been mentioned. Lime, magnesia, and alkaline bases unite with the 
disinfectant when it has acid properties. The volatile oil is then 
only slowly evolved by the action of the carbonic acid of the atmo- 
sphere. Sand is too coarse for general use, but infusorial earth 
and artificial silica (Calvert), being inert bases, give off the volatile 
matters completely. For use in wet places, such as urinals, inorganic 
bases are the best ; while for stables, rooms, «fec., sawdust and peat are 
most serviceable. Plaster of Paris and cement are sometimes used ; 
whilst dry earth and burnt clay are suitable for rough work. 

The Oxidising Power of Essential Oils. — Sanitas. — Schonbein first 
observed that in all slow processes of oxidation a small quantity of the 
oxygen is converted into ozone. This is the case in the slow burning 
of phosphorus. If any organic matters be present, they are rapidly 
oxidised by the ozone formed. He remarked that oil of turpentine 
and other essential oils were specially active in this way, and that 
ozone, probably from being continually re-formed, was permanently 
present in small amount as long as any oxygen was left. 

He attributed the purifying action of perfumes entirely to this 
ozonising effect. But Angus Smith J proved by experiments that the 
explanation v.'as not suflacient, and that their antiseptic action must 
also be taken into account. He suspended ozone paper (blotting- 
paper dipped in potassium iodide and starch paste) in a large flask 
containing a thin layer of the essential oil, and judged the amount of 

* Lees, Patent No. 1,738, 1893. t Patent No. 6,209, 1887. 

:;: Disinfectants, Edinburgh, 1869, p. 1 18. 



ozone by the degree of blueing of the paper, taking 10 degrees as an 
arbitrary maximum. He gives the following table : — 

Degree of Blueing of the Ozone Paper. 


After 18 hours. 


48 hours. 

72 hours. 

Oil of Orange-peel, 


Strong Colour. 



Essence of Turpentir 

le. Feeble. 




Oil of Juniper, . 





„ Cumin, . 





„ Lavender, 






Phenol, pure, . 



Creosote (Wood), 



Pyroligneous Acid, 




Oil of Thyme, . 


Naphthalene, . 


This test is not very delicate, as there is no doubt that traces of 
ozone are produced with all the above compounds except naphthalene. 
Other observers have found oil of thyme to give more than cresol. 
Yet the fact is obvious that the antiseptic action is not proportional 
to the small quantity of ozone formed, though the slight disinfectant 
power may be. Although, relatively, there is only a mere trace of 
ozone, amounting perhaps to 1 in 1,000, nevertheless it may form a 
considerable quantity in a large volume of air. 

Scoutteten * found that ozonised air rapidly removed the odour of 
foul manure ; Kichardson and Wood, that of putrid blood that had 
been kept in a flask for two years. Bond attributed the disinfecting 
action of permanganate to its production of ozone, f Boillet proved 
that ozone not only destroyed a putrefactive odour already formed, 
but actually prevented putrefaction. J Chapuis collected the germs 
and dust from contaminated air by filtering it through cotton wool ; 
he then submitted some of the wool plugs to the action of ozonised 
air. On then placing the wool in a nutrient solution (wort), the 
untreated plugs caused rapid turbidity and growth, the ozonised ones 
remained clear for twenty days.§ From the known fact that the 
hygienic condition of a locality varied with the proportion of ozone in 
the air as shown by test papers, and that several epidemics liad been 
preceded by a sudden fall in ozone, he very naturally argued that 
ozone must have the power also of destroying pathogenic organisms. 

Miquel asserts that ozone attacks gaseous emanations before it acts 

• L'Ozone, Metz, 1856. 

t Compies Rendus, 1875, p. 1258, 

t Brit. Med. Joum., 1875, p. 239. 
§ Bull. Soc. Chimique, 1881, p. 290. 


on bacteria or spores. Subsequent investigations have sho\m that it 
does attack the latter (see Ozone). 

Thenard was one of the first to show, and Ireland,* Barlow,t and 
others to confirm, that this gas is a poison, and was capable of causing 
asphyxia and fatal bronchitis, and that even a very minute quantity 
was irritant to the mucous membranes. 

These facts have a direct bearing on the claim of many advertised 
** disinfectants " to give ozone. The odour of turpentine, the smell 
of a newly-painted house, even the proximity of a pine forest, though 
supposed to be good for consumption and pulmonary complaints, 
undoubtedly cause in many people considerable irritation of the eyes, 
nose, and lungs. Still, in most cases, the freedom of the air from germs 
produces manifest improvement. 

C. T. Kingzett, about 1874, noticing that in presence of excess 
of warm water, peroxide of hydrogen, which is not irritant, is produced 
in solution rather than ozone, together with oxidation products of 
the terpenes, which acted as strong antiseptics, introduced a new 
disinfectant under the name of " Sanitas." 

In the first patent | turpentine oil is floated to a sufficient depth 
on the surface of warm water in large jars called oxidisers, and 
•currents of warm air or oxygen are forced through the mixture 
continuously for seven to ten days, maintaining the temperature con- 
stantly at 60°. The proportions used are 9 parts of turpentine oil 
to 1 of water. 

Berthelot has also shown that oil of turpentine is capable of dissolving 
from 3 to 5 per cent, of oxygen. The action in the presence of water 
is, therefore, of a dual character, the atmospheric oxygen molecules 
simultaneously producing molecules of peroxide of hydrogen, HoOg, 
which dissolve in the water and oxidise the turpentine, yielding 
camphors, camphoric acid resins, minute quantities of formic acid, 
cymene, &c., and a substance named by Kingzett "camphoric peroxide." 
Part of these dissolve in the water, part remain in the oil. The 
products are : — 

1. "Sanitas fluid," of a light straw colour and pleasant aromatic 
odour. It contains camphoric acid, camphoric peroxide, and gives a 
distinct purple reaction with sulphuric acid and potassium bichromate, 
showing the presence of hydrogen peroxide, amounting, according to 
the Lancet, to such a proportion that twice its volume of oxygen is 
given off" when it is decomposed. 

2. " Sanitas oil," a brown syrupy liquid, lighter than water, and 
insoluble in it, but soluble in alcohol, and having a similar odour to 

* AnncUe8 de ffygiine, vol. xir., p. 439. t Joum. of Anal, and Physiol., 1S79. 

X No. 274, 1876. 


that of the liquid. "When shaken with water, the latter acquires 
a peroxide of hydrogen reaction which is not so strong as that 
produced by the fluid.* It burns like camphor with a sooty flame. 

Patent No. 5,572, 1882, added resin and resin oil, and camphor or 
thymol. Turpentine, oil of eucalyptus, and " camphor oil " are also 
among the ingredients used. 

The " Sanitas air purifier " consists of fine wood flour impregnated 
with camphoric peroxide. A Sanitas toilet soap is made, and soft 
soaps, veterinary washes, and emulsions of the oil with gums, &c. 
Patent No. 1,589, 1890 (Kingzett), refers to " oxidised turpentine mixed 
with soft or hard soap." In patent No. 276, 1887, it is proposed 
to use : — 

1. Tin instead of earthenware for storing, as Sanitas is not corrosive 
to metals. 

2. Sea water instead of ordinary water, as the hydrogen peroxide 
keeps better in a saline solution. 

3. " One or more antiseptics added before or after oxidation." 
Horgreavesf mixes Sanitas oil and other disinfectants with laundry 

blue for linen. 

Dr. A. B. Griffiths, in testing the germicidal powder of the various 
Sanitas preparations, and particularly of "Sanitas oil" as liquid and 
vapour, on the bacilli of diphtheria, tuberculosis, glanders, cholera, 
typhoid, and scarlet fever, found that : — 

1. "One-tenth per cent, of the oil was incapable of destroying the 
microbe of typhoid in bouillon, but 1 per cent, prevented its develop- 

2. "One-quarter per cent, completely destroyed Micrococcus scarlatlnce 
in nutrient gelatine, ^ per cent, prevented its development (six tubes 
in each case)." 

3. "Eight tubes, each containing 100 c.c. of nutrient gelatine, were 
inoculated with Bacillus diphtherice from pure sub-cultures of the 
microbe; and after three weeks' incubation at 20° C, h c.c. of Sanitas 
oil was added to each tube, and the incubation continued four days. 
As a result, the microbes in all the tubes were found to have been 
destroyed, as animals susceptible to diphtheria on being inoculated 
were unaffected." 

4. " The bacilli of tuberculosis and of glanders were destroyed 
respectively by 1 per cent, in six, and by ^ per cent, in seven days." 

5. " The spirilla of Asiatic cholera (Koch) in ten tubes of bouillon 
(slightly alkaline) were killed in five days by 1 per cent, of the oil. 
It was further demonstrated that it is quite impossible to inoculate 
gelatine plate cultivations containing 1 per cent, of Sanitas oil with 

* Lancet, vol. i., 1890, p. 809. t Patent No. 2,524, 1883. 


the microbe of cholera ; although when Sanitas was absent the microbes 
gave rise to colonies." 

6. An apparatus was fitted by which the vapour of Sanitas oil from 
a flask heated to 100° C. in a water bath was passed into test-tubes con- 
taining nutrient media in which the above-mentioned organisms were 
growing. They were all destroyed in from four to fifteen minutes. 
From this it is concluded that the vapour itself possesses genuine 
germicidal powers, and should be of service in the treatment of 
diseases of the throat and lungs. It must be remembered, however, 
that these are not quite the conditions under which the agent would 
be employed in practice ; the bacterial growths seem to have been at 
or near the surface of the nutrient gelatine, instead of having pene- 
trated deeply into the tissues. No mention is made as to whether any 
water was placed in the flask with the oil ; the vapour of a fluid with 
so high a boiling point as Sanitas oil seems hardly likely to pass over 
at the temperature of boiling water except in the presence of steam. 

Dr. Bond, of Gloucester,* Dr. Poehl,t and Mr. Kingzett himself J 
have placed "Sanitas" and its varieties in the very first rank of 

On the other hand, Vallin§ says that the statements should be 
accepted with reserve, admitting, however, that " this product, being 
unknown in France, we have not been able to experiment on its 
efficacy." Harding Crowther|| points out that equal parts of vaccine 
lymph and Sanitas fluid did not prevent the inoculation succeeding. 
It might therefore be used as a preservative. 

Tripe and Stevensonll and Longstafi" and Hare,** after numerous 
experiments, arrived at the conclusion that " the Sanitas fluid and 
powder do not disinfect better than slaked lime;" they recognise, 
however, that this substance retards putrid decomposition, but that 
"it is little active in deodorising substances already putrid." 

It is obvious that Sanitas, like some other preparations, has sufiered 
by being over extolled ; its chief points of interest are : — 

1. The " fluid " is non-poisonous, non-corrosive, and does not stain. 

2. It certainly oxidises most organisms and their products when in 
sufficient quantity and strength, say 1 or 2 parts per 100. 

3. In antiseptic power it is about equal to the cresol preparations 
and superior to the carbolic ; over both it has the advantage, shared 

* Brit. Med. Joum., 1876, p: 239. + Sevue d'hygiene, 1879, p. 510. 

t Sanitary Record, 1879, p. 370, and 1880, p. 348. 

§ Diainftctants, 1882, pp. 177 and 316. II Med. Times and Gaz., 1879, p. 361. 
^ Med. Times and Oaz., 1880, p. 51, "Disinfectants in contradistinction to 
Deodorants and Antiputrefactive agents." 
♦• Sanitary Record, 1878, p. 353. 


with permanganate and the halogens, of chemical destruction of the 
microbes and of exhalations. 

4. Its action on sulphuretted hydrogen is not great, that on ammonia 
is almost 7iil. It can, however, be used with an absorbent like chloride 
of zinc, but not with ferrous sulphate, sulphurous acid, or other re- 
ducing agents. 

5. Its price is decidedly higher than some other disinfectants if 
quantity required be considered. A " Sanitas water-cart block, con- 
sisting of Sanitas in a highly concentrated (solid) state," intended to 
be placed inside the cart for disinfecting streets, has been proposed, 
but it is more than doubtful whether this could be done efficiently 
•except at a prohibitive cost. 

6. It is valuable for toilet use when a persistent odour is not an 
objection. Many people find it very agreeable. It ranks about equal 
to sodium hypochlorite (liquor sodse chlorinata, p. 63). 

7. More evidence as to its stability or constancy of composition is 

8. Further independent investigations as to its efficacy in epidemics 
like typhus, cholera, &c., as to the poisonous dose of " Sanitas oil," and 
whether it has irritant external effects, seem also desirable. 

Kingzett calculates that the eucalyptus forests of New South "Wales 
and South Australia alone contain, at any moment, sufficient oil in 
the leaves, ready to be evaporated into the atmosphere under the 
-agency of warm winds, to form no less than about 93 million tons of 
peroxide of hydrogen, and 507 million tons of camphoraceous prin- 

A fluid called " Pinol " is advertised, derived from Pinus pumilo. It 
resembles other terpene preparations, but is somewhat more pleasant 
in odour. We have no experience of its efficiency. 

The Wandsworth Chemical Works manufacture "the Pineotas 
series," including fluid, oil, sawdust, and soap, also carbolic prepar- 
ations, sheep dips, &c.t 

* Social Science Congress, Manchester, 1879 ; also see the same author's Nature''8 

t For further chemical information as to the terpenes and their derivatives, see 
O. Wallach, Liebig's Annalen, vols, ccxxvii., ccxxx., ccxxxix., ccxlvi., &c., also 
■on essential oils, &c., Journ. Soc. Chem. Ind., 1888, p. 226. 

On cresols, Frankland and Ward's Second Report, abridged in Journ. Soc. 
Chem. Lid., 1893, pp. 1,051-3. 

On phenol and camphor in antiseptic dressings, see Gosselin and A. Bergeron, 
Comptes Rendus, Sept 29, 1879, " Experiments on the Behaviour of Blood mixed 
with known quantities of Phenol, Alcohol, and Camphorated Spirit." 



Methyl Alcohol: Wood Spirit — Methyl Chloride — Chloroform — Methene Bi- 
chloride. Formic Aldehyde or "Formalin": its Properties and Disinfectant 
Value — Action on Bacteria — Other Aldehydes. Ethyl or Ordinary Alcohol : 
Not a Reliable Antiseptic except when Concentrated — Higher Alcohols — 
Acetone. Formic Acid and Sodium Formate. Acetic Acid : Aromatic 
Vinegar — Acetic Acid as a Poison — Pyroligneous Acid — Acetates. Glycerine : 
its Uses — Glycerine Soaps — Preservation of Food. Oleic Acid, Oils, and 
Fats: Lanolin. Petroleum: Hexane — Vaseline. Vegetable Acids : Tartaric, 
Citric, Malic, Oxalic, Succinic. 

Methyl Alcohol, CH3.OH, is a colourless liquid closely resembling 
ethyl alcohol, but boiling at a lower temperature, 66° C. In the 
crude form of wood spirit it has long been used to preserve anatomical 
specimens, owing its efficiency in great part to the creosote, &c., it 
contains. It is fatal to insects and micro-organisms in the moderate 
proportion of about 5 per cent., and were it not for its volatility and 
the fact that its vapour when mixed with air is explosive as well as 
narcotic, it would take a high rank as an antiseptic. Its relative 
cheapness makes it a better vehicle for those aromatic antiseptics 
which are insoluble in water than ethyl alcohol, which is commonly 

Tollens has devised a lamp for the slow combustion of methyl alcohol, 
forming formaldehyde, and thus ensuring aerial disinfection.* 

Methyl Chloride or monochlormethane, CH3CI, is a colourless gas of 
sweetish odour, soluble in water, and neutral, compressible by a pres- 
sure of 3 to 7 atmospheres into a colourless liquid, boiling at 21° C, 
in which state it is sold in commerce in iron cylinders. Its vapour is 
antiseptic, but no experiments are extant as to its relative value. 

Methene or Methylene Dichloride, CHoCI^ (boiling point, 42° C), is 
very similar to, but less powei'ful than, chloroform. 

Chloroform, trichlor methane, CHCI3, has already been referred to 
<p. 76). 

Formic Aldehyde, Formaldehyde, or "Formalin," H.COH, is only 
known in solution and in a state of vapour, since if an attempt be 
made to condense it, it polymerises to a white crystalline solid called 
para-formaldehyde, CgHgOg. Formaldehyde is readily soluble in water, 
giving, if perfectly pure, a neutral solution ; commercially it is always 
slightly acid, from the presence of a little formic acid. The odour is 
* Ber. d. deutach. Chem. Gesells., 1895, vol. xxviii., p. 261. 


very pungent, causing irritation to the eyes and nose. It is not a 
poison. The aqueous solution is stable when kept in well-closed 
bottles, but loses some of the gas on exposure. Loew and Fischer, in 
1886,* discovered that it possessed powerful antiseptic properties; 
Trillat, in 1888, showed that the presence of a minute quantity of this 
substance in urine effectually preserved it from putrefying. In a 
further paper he remarks that " hitherto it has been thought that the 
most powerful antiseptic bodies belonged to the hydroxyl compounds 
of the aromatic series of hydrocarbons (the phenols) and to the metallic 
salts. Formaldehyde is, however, a very powerful antiseptic, being 
actually superior to bichloride of mercury in this respect. The result 
is quite unexpected, as acetic aldehyde does not possess this property."! 
It is prepared by passing methyl alcohol vapour mixed with air over 
a red hot platinum spiral or heated platinised asbestos, condensing 
and purifying the vapours. | 

Buchner,§ Aronsohn,]] and F. Cohnll have investigated the pro- 
perties of formaldehyde, while Lehmanu, Gegner, and Blum** have 
examined its value as a general disinfectant, and Stahl,tt Hauser,|| and 
Liebreich S§ have reported on its suitability for special purposes. All 
these writers are agreed in attributing to formaldehyde powerful anti- 
septic and deodorant properties. Blum, however, points out that 
micro-organisms are only killed in somewhat strong solutions (2 per 
cent.). A recent paper by C. Slater and the author confirms Blum's 
statements, jl II 

With reference to the antiseptic power of formaldehyde, Trillat 
states HIT that " the addition of 1 to 50,000 to meat extract had a 
decided preservative action, while with 1 in 25,000 no change could 
be noticed in the extract after the lapse of four days. Mercuric 
chloride in these proportions has no effect, the extract showing change 
in twenty-four hours. "With 1 in 12,000 the extract is kept good for 
several weeks, while change occurs in five days when using an equal 
weight of mercuric chloride. Several kinds of bacilli are destroyed by 
a solution of 1 in 25,000, such as that of the saliva, &c." For the 
preservation of meat, Trillat tried (1) immersion in the solution, 
(2) exposure to the vapour, (3) wrapping the goods in coverings soaked 

• Journ.f. praktische Chemie, vol. xxxiii., p. 221. 
t Monileur ScienL, 1892, p. 490. 

:{: Trillat and Berlioz, Compt. Rend., vol. cxiv.,p. 1,278 ; cxv., p. 290; cxix.,p. 563. 
§ Munch. Med. Wochenschr., 1889, No. 20. |1 Berlin Klin. Woch., 1892, p. 749. 
IT Botan. Centralblatt, 1894, p. 573. ** Munch. Med. Woch., 1893^ p. 32. 

t+ Pharm. Zeit., 1893, p. 22. Jt Miinch. Med. Woch., 1893, pp. 567 and 655. 
§§ Therap. Monatschrift, voL iv., p. 183. ||li Lancet, April 21, 1894. 

HIT Moniteur Scientifque, 1892. 



with the aldehyde solution. One hour's soaking in a 1 in 500 solu- 
tion preserved the meat for twenty-five days; five minutes with a 1 in 
250 solution kept it for twenty days, when exposed to air at 23° to 
30° C. " The vapour was found to stop all decomposition, keeping 
meat fresh for months and stopping fermentation in organic liquids." 

Carabier and Brochet have shown that by heating dioxymethylene, 
the vapour of formaldehyde produced effects the complete sterilisation 
of household dust.* 

Slater and Rideal's re-examination, f in which formaldehyde was 
added to tubes of bouillon in proportions varying from 1 in 1,000 to 
1 in 20,000, the tubes then inoculated with vigorous cultures of 
different micro-organisms, and placed in an incubator, showed the 
following results for inhibitory action : — 

Proportion of 





allowing some 


Staphylococcus pyogenes aureus, 

lin 5,000 

1 in 10,000 

Growth poor — 1 in 
10,000, and much 
delayed 1 in 20,000. 

Bacillus typhosus, 

1 in 15,000 

1 in 20,000 

Very scanty growth. 

,, coli communis. 

lin 7,000 

1 in 10,000 

After seventy-two 
hours' incubation. 

„ atithracis. 

1 in 15,000 

1 in 20,000 

Scanty growth on 
sixth day. 

Spirillum cholerce. 

1 in 20,000 

• •• 


Bacillus mallei, 

1 in 20,000 

• •• 

... ... 

,, pyocyaneus. 

1 in 7,000 

1 in 10,000 

On the third day. 

„ lacticus, . 

1 in 20,000 


„ hutyricus (Hueppe), 

1 in 20,000 



Micrococcus prodigiosus. 

1 in 20,000 


The authors remark, " This would place formaldehyde among the 
first three or four antiseptics in Koch's tables. It is to be noticed 
that even when the proportion is too small to prevent growth, the 
cultures then obtained are scanty, and their development is long post- 
poned. The fact that growth does not take place in the bouillon is 
not proof that the microbe has been killed. Thus Bacillus mallei, 
which showed no growth after four days' incubation in a 1 in 15,000 
strength, when transferred to a fresh nutrient solution, gave rise to a 
culture normal in all respects, except in requiring an unusually long 
time to develop. Blum has shown with regard to anthrax that ex- 
posure to the antiseptic does not cause attenuation." As to commercial 
yeast, 1 in 2,500 of wort was required to prevent fermentation. In 
lesser quantity the rapidity was diminished, but the final amount of 

Compt. Rend., vol. cxix., p. 607. 

-f Lancet, April 21, 1894. 


alcohol was the same as if no antiseptic had been added. Hence 
formaldehyde might be useful fo arrest secondary fermentations in 
alcoholic liquids. 

To determine the amount required to kill microbes, sterilised silk 
threads were soaked in cultures of the various micro-organisms and 
then transferred to the antiseptic. After exposure for various periods 
the threads were withdrawn, well washed in sterile water, transferred 
to bouillon tubes, and kept at 37° C. for more than eight days. The 
tubes in which no growth took place were tested by inoculation in 
order to determine whether they were still suitable for growth of the 
microbes or whether the sterility was due to transferred antiseptic. 
They all yielded copious growth on second inoculation. Control ex- 
periments v/ere made in all cases. The results obtained were : — 

" Time required to kill the microbes with a 1 per cent, solution. 
S. pyogenes aureus, between 50 and 60 minutes ; B. typhosus, 40 to 50 ; 
B. colt communis, 30 to 40; B. anthracis and S. cTwlerce, less than 15 

" With a 1 per 10,000 solution (threads examined every half hour, 
at first, then hourly, then every twenty-four hours), B. anthracis (no 
spores) killed in thirty minutes ; S. cholerce in two hours ; but putre- 
faction organisms were not killed after twenty-four hours. Experi- 
ments were made to see how far these solutions might replace the 1 or 
2 per cent, solution of carbolic acid frequently used for the disinfection 
of soiled linen before washing. Soiled clothes from the post-mortem, 
room and sterilised clothes soaked in cultures were left for from twenty 
to twenty-four hours in 1 per cent, and 1 per mille solutions of 
formaldehyde. After washing in sterile water they were examined 
by cultivation : — 

1 per cent, 
solution. 1 per 1,000. 

Clothes from 2>os<-»iortem room, . . Sterile. Not Sterile. 

Clothes soaked in B. typhosus, Spirillum 

cholercB, or St. pyog. aureus, . . „ Sterile. 

" The solutions are without any ill effect on clothes, and are efficient 
as antiseptics, more especially the 1 per cent, solution, and the more 
so as in practice the adherent formaldehyde solution would not be 
removed." It seems especially suited for the disinfection of leather 
goods and general articles, like combs and brushes, which cannot be 
satisfactorily sterilised in other ways. 

The action of the vapour evolved at 19° 0. from a 40 per cent, 
solution was examined by exposing to it glass slips of dry bouillon 
cultures under a bell-jar for ten minutes, B. typhosus and coli; M. 
prodigiosus and Sp. cholerce were killed in less than ten minutes ; S. 
pyogenes aureus in twenty ; B, pyocyaneus in thirty minutes. As to 


the disinfection of rooms, 1| ounce of 40 per cent, formaldehyde was 
evaporated by a spirit lamp in a room of 1,548 cubic feet (about 11^ 
feet side). The dust was disturbed by vigorous sweeping, then ex- 
amined bacteriologically. After four hours' exposure to the vapour, 
the dust was again disturbed, and a sample examined. In other 
experiments threads soaked in various cultures were suspended at 
different heights and at about 3 to 5 feet from the source of the 
vapour. The results were not decisive, but showed decided eflfects of 
the vapour. There is no reason why much larger quantities of the 
antiseptic should not be used. The air before disinfection contained 
429 organisms for 10 litres, afterwards only 71. 

The threads after disinfection in all cases produced more scanty 
cultures and more slowly. Some of those impregnated with B. typlwsus^ 
and coli were sterile. 

It seems also to be possible to sterilise the skin with formalin, and 
as it does not hinder the formation of a lather with soap, as mercuric: 
chloride does, it seems a desirable substitute. 

Trillat states that formaldehyde precipitates the tannin and colouring 
matters of urine. It is also incompatible with ammonia, forming with 
it a non-volatile crystalline compound. It is of course a reducing- 

In commerce it is found as "Formalin," a solution in water con- 
taining about 40 per cent, of formic aldehyde with a minute trace- 
of formic acid, made by Schering of Berlin. A " formalin " dusting 
powder is also available. 

Berlioz and Trillat say that the vapour can be inhaled or injected 
in throat and lung disease with marked benefit and without toxic 
effects.* J. Stahl generally confirms the value of formaldehyde. f 

Ethyl aldehyde and paraldehyde seem to be useless as antiseptics. 
Chloral has properties similar to those of chloroform. 

Alcohol, 02Hj(0H), coagulates albumen, hardens animal tissues^ 
and renders them imputrescible, hence it is used for preserving 
anatomical specimens, bodies, <fec. For this purpose the old form of 
** methylated spirit," containing 10 per cent, of crude wood spirit, is 
better and cheaper. The new form, mixed with petroleum, is not 
available, as it becomes turbid with water ; for other antiseptic 
purposes, however, it is equally serviceable. 

Bucholtz observed that a 1 in 30 solution of alcohol did not prevent 
the development of vibrios. J Calvert and M'Dougall found that 1 in 
20 prevented the putrefaction of beef-juice and egg-albumen for six 
days. Wemitz established the fact that 1 in 3 to 1 in 10 destroyed 

♦ Comptea Rendus, vol. cxv., p. 290. + Pharm. Zeit., 1893, p. 173. 

+ Archiv.f. exp. Pathol., 1875, p. 159. 


the activity of non-organised ferments (ptyalin, Sic.).* Jalan de la 
Croix t found that it required a solution of 1 in 21 to prevent the 
growth of adult bacteria transferred into bouillon, but the organisms 
were not killed below 1 in 4*4, or 22 per cent., and the germs not 
below 1 in 1-18, or 83 per cent. Meat broth freely exposed to air 
remained free from bacteria when the proportion was 1 in 11, Gosselin 
and Bergeron I exposed fresh blood in vessels covered with folds of 
muslia to the vapour of strong spirit under a bell-jar. Putrefaction 
was deferred to the eighth day by six drops of alcohol, whereas natur- 
ally it would have appeared on the third or fourth day. Miquel's 
statement is that " 95 parts of alcohol neutralised 1 litre of beef tea," 
about 10 per cent.§ 

It has been suggested that the gradual re-appearance of bacteria 
when the solutions are exposed to air is due to the loss of strength 
by evaporation of the alcohol. But Geissler has disproved this, 
finding that open tubes containing a mixture of water and alcohol at 
the end of seventy-two hours still contained 32 per cent, of alcohol, 
the original amount having been 33 per cent. So that, as with other 
antiseptics, the bacteria have the power of slowly becoming accustomed 
to their environment. || With alcohol this toleration appears to be 
very marked. 

Alcohol, therefore, in itself is not a reliable antiseptic, although it 
has been found useful for washing open wounds and even cavities. 
Here of course its absorption and stimulant action must be taken into 
account. With water, it is chiefly used as a vehicle for other com- 
pounds, to whose efficacy it adds. Indeed, in some cases it probably 
takes the principal part, the other materials, such as essential oils, ttc, 
being in such small quantities as to act mainly as scents. 

Dr. J. J. Ridge H describes the effect of minute quantities of alcohol 
on cell protoplasm, and points out that it causes a shrinkage of the 
protoplasm, by withdrawing water, slowly hardens and thickens the 
walls and hinders nutrition.** To these phenomena must be attri- 
buted its inhibitory action on bacteria, and its destruction even of 
germs, when the solution is strong. Minute quantities have no action 
in preventing putrefaction. Wines, for example, if of weak alcoliolic 
strength, become sour, and even putrid. A mixture of acetic ether 
and alcohol, with or without acetic acid, constitutes the antiseptic 
and preserving agent called "Salubrine." ft 

• Wirhung der Antiseptica, 1880. t Archiv. /. ezp. Pathol., 1881, p. 175. 

t Arch, de MM., 1881, p. 16. § Org. viv. de I'Atmosph., 1883, p. 289. 

II See Salicylic acid, p. 201 ; Watson Cheyne, Med. Times and Gaz., 1879, 
p. 561. 
IT Brit. Medical Association, 1890. ** Brit. Med. Journ., vol. i., 1891. 

•H- Hakansson, Patent No. 10,465, 1893 ; J. S. C. I., 1894, p. 898. 


Formic Acid, H.CO.OH, resembles its homologue acetic acid. Its 
antiseptic power is less than that of acetic and propionic acid, and 
according to Duggan,* in the series of fatty acids the antiseptic power 
is proportional to the molecular weights. Sodium formate, H.COONa, 
is a soluble salt resembling the acetate, but possessing reducing pro- 
perties ; it has the advantage of dissolving many compounds which 
are sparingly soluble in water alone, such as arsenious, boric, and 
salicylic acids, and it does not favour the growth of moulds like 
sodium acetate ; consequently it has been incidentally mentioned in 
several patents, as, for example. No. 3,153, 1882, "Boric acid melted 
with sodium phosphate and formate, can be cast into homogeneous 
solid cakes, which are inodorous, very soluble and almost tasteless; 
to be used by dipping or soaking to preserve provisions." It would 
leave a white efflorescent crust, which ^ would undoubtedly be anti- 
septic, and could easily be washed off. 

Acetic Acid, CH3,C0(0H), in the pure state or "glacial," is a 
crystalline solid melting at 17°, and boiling at 118° C; specific gravity 
1*055. It has a strong pungent odour, and is very caustic. The 
"strong acetic acid" of the British Pharmacopoeia contains about 
30 per cent, of real acid ; vinegar from 3 to 5 per cent. 

A more or less concentrated acid, scented with spices, was much 
used in the middle ages under the name of " aromatic vinegar," to 
drive away plague. Glacial acetic acid dissolves considerable quan- 
tities of camphor and essential oils, and does not wholly deposit them 
on dilution. 

Acetic acid is the chief product of the action of Mycoderma aceti on 
alcohol. When it has reached a certain amount, it checks and finally 
stops this fermentation, and, if sufficiently strong, it inhibits the 
growth of all bacteria, hence its use for pickles, <fcc. But, as is well 
known, if the vinegar be weak, it turns cloudy, and itself undergoes 
a putrefactive change. The old idea that vinegar is an antiseptic is, 
therefore, only a question of degree, inasmuch as most micro-organisms 
thrive best in a neutral or alkaline medium ; any acid whatever will 
act as a restrainer of their growth (see Hydrochloric and Sulphuric 
acidSf pp. 69 and 97). Calvert and M'Dougall say that 10 per cent, 
of acetic acid was necessary " to prevent animalcules in beef-juice and 
egg-albumen for six days. The effect of 10 per cent, on animalcules 
in already putrid beef-juice was none." Liebig defended the popular 
opinion by pointing out that it fixed ammonia and the organic bases 
Accompanying fermentation.! 

" Aromatic vinegar," diluted with water, is frequently used to bathe 

ihe bodies of patients in typhoid fever and scarlatina; it certainly 

• Am. Chem. Joum., voL vii., p. 12. t Vallin, Diamfictants, p. 155. 



assists desquamation, acts as a cooling tonic to the skin, aftd removes 
or hides any offensive odours. It lends itself admirably to mixing 
with resorcin or a sulphocarbolate (p. 158); so yielding a powerful 
and eflBcient antiseptic. The acetates are not antiseptic. 

Pyroligneous Acid, or crude vinegar, is used in curing hams and 
fish. It owes its undoubted antiseptic power chiefly to the creosote it 

Propionic acid, C2H5COOH, has been tested by Duggan on 
B. subtilis.* 

Glycerine, C3Hg(OH)3, is a colourless, inodorous, and neutral syrup, 
of specific gravity 1*27, boiling with partial decomposition at 290° C. 
It is miscible with water and alcohol, and dissolves a large number of 
salts and organic compounds. Under ordinary circumstances it is not 
fermentible. Strong solutions are antiseptic, but weaker ones undergo 
fermentation, yielding butyl alcohol, caproic and butyric acids, and 
other products of very disagreeable odour. It has been used for the 
following purposes : — 

. 1. On account of the sweet taste, non-fermentibility, and antiseptic 
tendency, it is largely used for sweetening wines, temperance drinks 
(e.g., " Hygeia "), syrups, artificial cordials, and " British wines," and 
for the preservation of beef-juice extracts. On this subject Lehmann 
remarks! : "An addition of glycerine, as it can be practically applied, 
should not be pronounced hurtful, for, even if large quantities of 
glycerine taken at once act as a purgative (say 15 to 30 grammes), and 
if very large quantities have an action resembling that of alcohol, there 
is no doubt that the addition of a few grammes of glycerine (5 grammes 
per litre) is perfectly harmless in such dilution. Experiments on the 
guinea-pig, a very susceptible animal, prove ^ gramme daily per kilo- 
gramme of body weight can be mixed with food without injury." 
Miquel J says that to prevent putrefaction of bouillon it is necessary 
to add 225 grammes of glycerine of specific gravity 1-25 to a litre — 
a very large dose, which implies that an amount to preserve food 
would also confer a penetrating and unpleasant sweetness. It has 
also been employed instead of sugar in beverages for diabetic patients, 
but causes purgative and griping effects. No prosecution is recorded 
under the Food and Drugs Acts. 

2, In surgery, to keep the skin pliable. It does not maintain the 
surface moist, as, being very hygroscopic, it acts as a drier ; on this 
account its habitual use for the hands or face i^ well known to make 
the skin transparent, thin, and wrinkled. Bacteria and insects are 
killed by undiluted glycerine, since, having very low diff'usive power, 

* Am. Chem. Journ., vol. vii., p. 62. t Hygiene, 1893, vol. xi., p. 247. 

X Org. vivantSf chap. 9. 


it causes death by desiccation. Germs, with thicker envelopes, resist 
it indefinitely, and on dilution commence growing rapidly. Its 
chief use has been as a medium for other medicaments, which it 
keeps liquid and allows to readily diffuse. It is largely employed in 

3. Glycerine soaps do not enjoy the same repute as formerly, on 
account of the above-mentioned objectionable action on the skin if 
their use is long continued. " Glycerinum saponatum " is largely used 
by Prof. Hebra in his clinic at Vienna by reason of its rapid solubility 
in cold and warm water, and its advantageous property of dissolving' 
a large number of substances and of holding other pulverulent insoluble 
substances in suspension.* It is a faintly yellowish, more or less 
elastic mass, perfectly inodorous, and melting at the body temperature. 
Its composition varies from 80 to 92 per cent, of glycerine, with 20 to 
8 per cent, of a neutral cocoa-nut oil soda soap. 

4. Hams and dried fish have been soaked in 20 per cent, glycerine 
with the idea of preservation. 

Boroglyceride has been described at p. 101. 

Oleic Acid, the fats, "Lanolin," &c., have no antiseptic power in 
themselves, but act as convenient vehicles for the application of anti- 
septics. Oleates of mercury, zinc, <kc., have, within late years, been 
found to possess a rapid absorption, to be more powerful than simple 
ointments, and to be less irritating. It has been pointed out (p. 151) 
that " carbolic oils " are less efficient than aqueous solutions. 

Oils and ointments when applied to the skin may prevent infection 
by the exclusion of the germs, but Vicario has observed that the 
fixed oils may contain germs, and that both they and any solutions 
to be mixed with them must be sterilised by heating to 100° C, or 
preferably to 120° C, in a digester, especially in the case of hypo- 
dermic injections of guaiacol, iodoform, and eucalyptol with olive oil, 
for phthisis, kc. f 

Petroleum Jelly and the paraffins, although almost insoluble in 
water, are used diffused through it or through soap and water, as in- 
secticides in horticulture. Under the name of vaseline it is used as 
a medium for antiseptic compounds. 

Marco Polo, in the thirteenth century, said that petroleum from the 
Caspian Sea was used "to anoint camels that had the mange."f 

Vegetable Acids, like tartaric, citric, and malic, have the general 
power of inhibiting bacteria which prefer a neutral to an acid medium, 
but their effect is much less than that of mineral acids, and, as is well 

• Pharm. Zeit., July 19, 1890; Pharm. Joum., 3rd series, vol xxi., p. 1,040. 

t American Druggist, June 15, 1891. 

t Encyclopcedia Brilannica, vol. iii., p. 259, 


known, their solutions quickly become covered with mould in warm 
weather. Reinsch * states that '028 per cent, of tartaric acid in water 
" began to diminish the bacteria, and 0'2 per cent, killed them." 

Patent No. 1,297, 1893, proposes the use of tartaric acid for purifying 
water, and a filter has been devised to carry out this idea. Many 
patents use tartaric and malic acids to increase the solubility of boric 
acid and borax {q.v., p. 102) ; it would seem as if they would rather 
diminish the eflficiency by providing nutrient material, as exemplified 
by Pasteur's solution, which is used for growing organisms. 

Oxalic Acid is an irritant and corrosive poison, and is said to be 
antiseptic. Its solutions certainly do not develop organisms; even the 
oxalates only allow their growth slowly. But in practice they are 
inapplicable. Succinic acid is slightly antiseptic. 


Towns : Limited Areas — Administration. Sewers and Drains : Ashpits and 
Dust-Holes. Houses : Walls and Wall Papers — Furniture and Wood Work 
— Sinks. Sick Rooms : Isolation — Clothing — Excreta — Removal — Light and 
Air — Spray — After- Disinfection — Phenol — Sulphurous Acid — Chlorine — 
Liquid Disinfectants by Spraying — Hot Solutions — Cisterns — Water-Closets 
— Earth-Closets — Middens — Cesspools — Infection by Flies — Automatic Dis- 
tributor — Wood Paving — Urinals — "Urinal Cakes"— Stables — Pigstyes and 
Cowsheds — Cattle Markets and Fairs — Slaughter-Houses — Dairies — Bake- 
houses — Pigeon and Fowl Houses — Rabbit Hutches— Cats and Dogs — Vehicles 
— Skins, Furs, Wool, and Hair — Rags. Disinfection of Air : Impurities — 
Sewer Gas — Vaporisers and Filters for Air — Water and its Purification. 
Preservation of Timber : Copper Sulphate — Creosote Oils. 

In early times it was almost considered presumptuous to combat by 
natural methods the great plagues which frequently devastated the 
country, and only trifling efforts were made to control the ordinary 
infectious diseases that are always with us, such as diphtheria, typhoid, 
and other fevers. It is true that vinegar, camphor, and perfumes were 
used to protect the person from contagion, and that fumigation with 
aromatic woods was sometimes employed, but these, as has already 
been shown, have only feeble powers in this direction. As the popula- 
tion increased, and overcrowding in towns became general, the fatality 
from epidemics became excessive. Amulets of all kinds were the only 
remedies relied on. Even now, in the bubonic plague which was 
* Centrcdhl.f. BahterioL, 1891, vol. x., p. 415. 


recently raging in Hong Kong, the faith of the people in charms, 
and their opposition to sanitary measures, was so intense that it was 
only under military force that the work of sanitation could be under- 
taken. Yet it is scarcely open to doubt that this plague, identical in 
its symptoms with the great plague of 1666 and other years, as shown 
recently by Kitasato, and is still endemic in certain parts of the East, 
the Black Death, and the Sweating sickness, and, to a great extent, 
the cholera, are only kept out of Europe by modern applications 
of sanitary science. Harvey in the sixteenth century, and Bishop 
Berkeley in the eighteenth, seem to have been the first to advocate 
the combating of disease from the outside. England was the first 
nation to organise a systematic campaign against infectious diseases. 
After the great outbreak of cholera in 1832, Parliament energetically 
resolved to frame regulations for public health. These emanated 
from the elected authority, and not, as in other countries, entirely 
from the police. The Public Health Act of 1848 constituted the 
Local Government Board as the executive sanitary power. Statistics 
were collected. The country was divided into limited areas, which 
were distinguished as Urban and Rural Sanitary Districts, each with 
its Local Board of. Health. The Urban districts included all towns 
except London, which has a special sanitary organisation. Scotland 
and Ireland also have in part their own laws. The Urban authority 
centred in the Town Council. In rural districts the Board of Health 
and the Guardians are now merged in the Rural District Councils. 
Each body sends an annual report to the Local Government Board, 
which from time to time sends out recommendations in the form of 
a circular to the Local Authorities. Measures of disinfection are per- 
formed, superintended, or directed by the Sanitary Officer (Inspector 
of Nuisances) under the control of the Medical Officer of Health. 

Sewers and Drains. — It has already been pointed out that the old 
system of pouring large quantities of liquids, like carbolic acid, sul- 
phate of iron, or permanganate down the drains with the object of 
disinfecting the sewage, is really useless, inasmuch as the reagents 
are practically lost in the immense volume of water, and fail to 
reach a proportion sufficient to destroy the bacteria, although they 
may partially remove the smell. If an attempt is made to hermeti- 
cally close the sewers, as was formerly supposed to be the best method 
for preventing a nuisance, the sewer gas, by backward pressure of 
rains or tides, passes through any form of trap into the houses, and, 
although sewer gas has been proved, probably owing to subsidence in 
the quiet atmosphere, to be almost free from germs,* yet there can be 

* Joum. Soc. of Chem. Ind., 1888, p. 911 ; also J. Parry Lawes' Report to the 
L. C. C, 1893. 


no doubt that it has a depressant effect, and lowers the vitality in such 
a way that men subjected to its influence are therein predisposed to 
infection. The fact that a few germs may be present must also be 
borne in mind. Consequently, the modern system is mainly confined 
to ventilation and flushing. Charcoal and disinfecting ventilators 
are elsewhere discussed (p. 246). Drs. Arthur and Illingworth have 
recently proposed a new system of sewerage in which the side drains 
enter at the bottom of the main sewage.* 

In workmen's dwellings it is customary in London for the gratings 
of the house drains to be daily sprinkled with some disinfecting 
powder. M'Dougall's, Calvert's, or a pine-oil powder such as Sanitas, 
are commonly used. In a number of experiments on this practice, 
gratings were selected which evolved a distinct quantity of sul- 
phuretted hydrogen, as proved by lead paper 1 foot over the drain 
being in most cases discoloured. After sprinkling with either of the 
powders, the fetid odour, both of sulphuretted hydrogen and of sewage, 
seemed to be actually removed, and not merely disguised, as the lead 
paper was no longer affected. The effect, however, only lasted from 
an hour to an hour and a-half ; after this the smell was as strong as 
ever, and the lead paper was again discoloured. The odour was 
most powerful in the mornings, or on the approach of a thunder- 
storm. It may be mentioned that in this instance several cases of 
diphtheria had occurred, and a general cachexia was noticed in 
the inhabitants, in all probability attributable to this sewer gas. 
Yet in many of these places, when a complaint is made, a roadman 
is sent with disinfecting powder, and the nuisance is temporarily 
abated, instead of the defect in the drain being seen to by the sani- 
tary inspector. So that this method of disinfection is not only 
useless, but is positively to be condemned, as it leads to a false idea 
of safety, and hinders genuine sanitation. Sanitary inspectors should 
always visit these places in the early mornings before the roadmen 
have sprinkled the disinfecting powder. 

Chloride of lime retains its power for a very much longer time, on 
a,ccount of the gradual evolution of chlorine by the action of the 
carbonic acid of the atmosphere. But even this is inefficient. Its 
smell to most people is exceedingly unpleasant, and the gratings and 
pipes are quickly corroded ; hence its general abandonment for this 
purpose. A daily flushing of the drains, except in rainy weather, with 
water seems to be one of the best methods for preventing a nuisance. 
It has been proposed in several recent patents to suck the smoke from 
house and other fires into the sewers, not only to get rid of the soot, 
but with an idea of disinfection, but as it is necessary for workmen to 
* Sanitary Feord, 1894. 


enter the sewers, it is not easy to see how the smoke could be tern-; 
porarily suspended. 

As to Ashpits and Dust-holes, if they are frequently emptied, and 
care is taken to burn putrescent matter and not to throw it into these 
receptacles, there is not much danger. Portable ash-bins of galvanised 
iron are much used in London. To sprinkle disinfectants over the 
refuse is futile, though they may be used with some advantage in the 
empty dust-bin after removal, and over the contents of the dust-carts 
in their passage through the streets. Stingl and Neuman have a 
patent* for an improved refuse collecting van, with double dust closure 
and an automatic disinfecting device. A portable petroleum destructor 
for house refuse has also recently been advocated for this purpose. 
Most urban authorities have now a difficulty of disposing of their 
refuse, and many refuse-destructors and cremators are now on their 

Houses. — Fresh air, light, and frequent cleansing seem to be the 
essentials to be aimed at in thickly-populated districts. In washing 
floors a strong carbolic soap, or better, a cresylic preparation, are very 
useful. Curtains and bedding must be occasionally brushed and 
shaken in the open air. When sweeping floors and carpets, teaJeaves 
or damp sawdust should be used to prevent the difi"usion of germs in 
the dust. Oil paint, or a well-varnished paper, are preferable for 
walls, as they can easily be washed. Flock papers have become 
obsolete, from their forming such a favourable nidus for the growth of 
organisms. Ordinary wall-papers can be cleansed down with the 
crumb of bread, which mechanically removes any bacteria. 

Hygienic Wall-papers prepared with various disinfectants incor- 
porated in the pulp have been suggested. Mercuric chloride has even 
been proposed to be introduced, but its use should not be permitted 
on account of the danger of its being evolved in the dust. Resorcinol, 
1 in 2,000, is patented by Sinclair and Brown for this purpose. f 
Salicylic acid is non-volatile and inodorous, but it is doubtful if it 
would be efficacious. It has been proposed to incorporate it with the 
plaster coating of walls (p. 198). It always communicates a pinkish 
colour, owing to the presence of iron salts. Herr Kosinski of 
Warsaw has invented a machine for drying and disinfecting walls. 
It is a portable air-heating chamber with pipes to the outside of the 
room, capable of heating surfaces of about 108 square feet by an air- 
blast directed by radiating pipes on to the wall or other surface. The 
air is mechanically renewed at the rate of about 1,000 feet a minute. 
It is also intended for large disinfecting chambers, in which the 
rapidity with which the air passes, combines with the high tempera- 
• No. 47, Jan., 1894. + Patent No. 12,217, 1886.- 


ture (stated in the report to be 660° F., but this is obviously an error) 
in bringing about the desired result. It is also suitable for warming 
buildings, and for removing vapour and moisture from crowded rooms 
— e.g., in a theatre, after the exit of the audience, to prevent the con- 
densation and settlement of injurious moisture and dust. An official 
commission at Warsaw proved that a private house, the building of 
which was commenced in May, 1882, with the capacity in ground floor 
and first storey of 7,000 cubic feet, was completely dried in fourteen 
days, and severe sanitary inspection proved the building to be com- 
pletely sterilised. 

Furniture and Woodwork can be washed and scrubbed, or, in special 
cases, should be washed with 1 in 1,000 mercuric chloride (in a few 
instances this may cause discoloration). Beeswax and turpentine 
are better than the common furniture polishes for polishing, as the 
surface is to some extent disinfected and rendered non-absorbent. 
All cracks and crevices should be carefully filled up with putty 
to prevent the lodgment of vermin or germs. 

Sinks, if made of stoneware, can easily be cleaned. Here Oondy's 
fluid (permanganate) is serviceable, but strong soda is ordinarily 
better. For toilet utensils sodium hypochlorite (chlorinated soda) 
in 5 per cent, solution should be occasionally used, also for milk 
cans and pails. In the case of metal baths it should not be used 
too strong as it removes paint. Bedsteads, in addition to scrubbing 
with soap and water, can be afterwards washed with chloride of 
lime and water, 10 per cent., and left in the air till the odour 
has almost disappeared. Paraffin oil is sometimes used, but its 
odour is very persistent. Polished floors are to be recommended 
in preference to porous floors and carpets. 

Sick rooms cannot be disinfected in presence of human beings. 
All placing of saucers with chloride of lime, permanganate, &c., 
under the bed, or about the room, all hanging up of sheets dipped in 
disinfectants, are simply illusory. Similarly fumigation by medicated 
lamps or candles, burning pastilles, or brown paper, are useless. 
Sufficient of the disinfectant to kill the micro-organisms of the air 
would make the air unfit to breathe. The following precautions, how- 
ever, will be of service. 

1. Isolation. — If possible, the other inmates of the house should 
live on a different floor. Where this, on account of poverty or other 
cause, is unattainable, contact should be carefully avoided. 

2. Clothing. — The attendants should wear cotton and linen, not 
woollen, garments. This is now compulsory in hospitals and most 
institutions. The greatest personal cleanliness should of course be 
observed. The following is the best way of removing soiled clothing 


from the room : — At the bottom of a large air-tight tin trunk, such as 
is used for travelling to India, is placed a piece of felt or blanket, or 
three or four thicknesses of flannel. This is sprinkled with crystals of 
carbolic acid, and covered with a linen cloth. The crystals will soon 
deliquesce, and soak into the stuff. The lid should never be left open. 
The soiled clothing is put in, and when full it is left for an hour for 
the phenol vapour to penetrate, and then carried out into a yard, 
where it is filled with boiling water containing soda, and washed as 
soon as possible. The washing must never be done, nor the clothes 
hung out to dry, on the same day as the ordinary house washing, nor 
should they be ironed or starched in the same room or with the same 
utensils. This dry method of removal of clothing is probably better 
than the usual one of plunging into a disinfectant solution (phenol or 
mercuric chloride), as it is easier, and the weight of the water and 
constant carriage are avoided. 

3. Excreta, vomit and sputa should be received into about a pint of 
mercuric chloride solution, 1 per mille, with 10 per millo of common 
salt and 1 per mille of hydrochloric acid, and coloured with indigo to 
avoid mistakes. A large quantity of such a solution should be kept 
ready. (See also p. 141.) Dr. Fischer recommends aniline water as 
the best disinfectant for tuberculous sputa (p. 184), "Five per cent, 
phenol did the same in twenty-five hours ; mercuric chloride, 1 in 500, 
failed. Dry heat of 100° C. sometimes failed, though it acted for sixty 
minutes. Boiling ten minutes, or steam for fifteen minutes, succeeded."* 
Disinfected excreta must not be thrown away before the agent has 
had time to penetrate. If disease begins in houses where the sick 
person cannot be properly accommodated and tended, medical advice 
should be taken as to the propriety of removing the patient to an 
isolation hospital. Where dangerous conditions of residence cannot 
be properly remedied, the inmates, while unattacked by disease, should 
remove to some safer lodging.! 

4. Light and air should be freely admitted. Vallin strongly recom- 
mends the use of water spray in the room, as he says that the water 
entangles the bacteria and dust, and the dissolved oxygen in the water 
destroys them. He also approves the use in the water of a small 
quantity of resol (dimethyl-resorcin), a body proposed by M. Pabst, as 
agreeable and non-corrosive. A 1 per cent, solution of peroxide of 
hydrogen, or a preparation like Sanitas might also be employed for 
the same purpose. The sick person should be protected by a screen 
from this process, from draughts, and from too much light. % It is 
well known what benefit is derived in some lung diseases from the 

* MUthe'U. Kais. Oesundh., 1884. t Circvlar of Med. Off. Local Gov. Board. 
X Dia'mfectants, p. 407. 


common bronchitis kettle. Dr. W. Ferguson has suggested its use 
as a fumigator in pneumonia and diphtheria by the following simple 
modification: — "Take an ordinary bronchitis kettle, remove the first 
joint, and replace it by a common tin funnel loosely filled with tow. 
Pour on the tow 1 drachm of pure phenol, and at intervals more. The 
steam carries off the phenol."* Curtains, hangings, carpets, and all 
^unnecessary furniture should be removed. 

After-disinfection. — Phenol, chlorine, and sulphurous acid have each 
had their advocates. 

{a) Plienol. — Pouring strong carbolic acid on a hot shovel is 
dangerous to the operator. Calvert manufactures a perforated iron 
cylinder delivering a mixture of 2 parts phenol and 1 part water on 
to a red-hot iron heater ; the whole is compact and can be carried by 
a hook. There is also Savory and Moore's vaporiser, in which phenol 
falls on a hot plate ; and many others. But phenol is not reliable as a 
disinfectant {Miquel and others), and the smell remains persistent. 

(6) Sulphurous Acid. — After the removal of such articles as are best 
disinfected by heat, and the closure of windows and crevices, the gas 
in ample quantity should be evolved, the doors being closed for six 
hours or more. The amount of gas required for the disinfection of a 
moderately-sized room can be obtained by burning 1| lbs. of roll 
brimstone in a pipkin over a small fire placed in the middle of a room, 
with an old tray or the like to protect the flooring. These processes 
should be effected by skilled persons acting under the directions of the 
Medical OflScer of Health. All wall-paper should be stripped from 
the walls and burned, and the same room ought to have its ceilings 
and walls thoroughly washed and lime-whited.f Boake's liquid sul- 
phurous acid, bottles or tins, are much more convenient in careful 
hands (see p. 92). 

(c) Chlorine. — 3 lbs. of good chloride of lime and 3 lbs. commercial 
hydrochloric acid should be used for every 1,000 cubic feet. This 
quantity should be divided into several parts and placed in deep 
vessels as high as possible (since chlorine gas is heavier than air), and 
the acid allowed to drop in gradually by a funnel partially blocked by 
a cork pierced with a small hole (try the dropping rate beforehand 
with water). The room should then be closed for twenty-four hours. 
Before opening, cover the mouth and nostrils tightly with a towel 
soaked in weak solution of ammonia, i to 1 per cent. Close the other 
doors of the house and open the windows. Sprinkle a little strong 
emmonia in the passage around the room door. Now open the sick- 
room door, rapidly throw the windows wide open, and as quickly 
r.etire. Another person similarly protected should be at hand in case 

* Lancet, 1880, vol. xi., p. 757. ' f Circular of Med. Off. of Health, L. G. B. 



of accident. If the eyes are affected, wash them with luke-warm 
water, without any ammonia. In case any irritation remains in the 
lungs or nose, inhalation of the vapour of ether will afford relief. 
With these precautions the operation is perfectly safe. All metal 
fixtures should be removed beforehand; if this is not possible, they 
must be well rubbed 
over with vaseline or 
lard. This is un- 
doubtedly the most 
thorough method of 

there is a 

Fig. 20. — The Equifex disinfectant sprayer. 

In both 
omission. Inasmuch 
as neither dry chlorine 
nor sulphurous acid 
will act, it is necessary 
to generate steam by 
a boiler or large kettle 
over a good fire for 
some hours before com^ 
mencing, so as to make 
the whole room and the 
air thoroughly damp. 
Then put out the fire, 
close the chimney, and 
proceed to the disin- 

(d) Non-volatile dis- 
infectants can be ap- 
plied by mechanical 
means. Thus bleach- 
ing powder can be used 
as a wash, and the 

walls, floor, and ceiling coated by means of a brush. Mercuric chloride 
solution and formalin, or, in fact, any liquid disinfectant can be sprayed 
into the room. The Equifex sprayers have been specially devised for 
this work. Two forms are shown in Figs. 20 and 21. The spray is so 
constructed that the fineness of division and the force and velo- 
city of projection can be varied at will. For this purpose the 
channel for the disinfectant is arranged to reduce the velocity of the 
liquid at the point of delivery to a rate which is very small, and 
capable of being exactly controlled by turning a cock. For a given 


Fig. 21. — The Equifex disinfectant sprayer 
(another form). 


velocity of air, regulated by another cock, the force of projection will 
therefore be determined by the velocity of the air, which is controlled 
by the pressure to which the pump is worked, and the degree to which 
the air cock is open. The importance of a fine division of liquid 
depends on the fact that it enables the work to be done with the 
minimum useful amount of disinfectant, saving the expense and incon- 
venience of waste liquid. 

The parts containing the disinfectant are lined with ebonite, so that 
these sprayers may be used with any liquid disinfectant without any 
risk. The cost will vary slightly with the disinfectant used. Taking 
perchloride of mercury 1 in 1,000 solution, it is found that an ounce 
of salt disinfects more than 3,000 square feet of surface. The time 
occupied in the operation is about an hour per 1,300 square feet. 

Clothes, bedding, mattresses must be removed at once in a closed van 
to a disinfecting station, to be treated with superheated steam. Dry 
hot air is now only used in special cases (books, leather, and some 
other materials), and in practice the apparatus is no longer constructed 
(see p. 27). Occasionally, however, a baker's oven may serve, if not 
for the destruction of the spores of splenic fever, for killing the non- 
sporiferous bacteria of cholera, typhus, and diphtheria, and especially 
of animal vermin {Klein). The bodies of persons who have died of 
infectious diseases should be at once wrapped in a cloth soaked in 
1 per cent, solution of mercuric chloride prior to burial or cremation. 
Adolf and Heider find that hot solutions of disinfectants are much 
more active than cold.* In Belgium infected clothes are boiled in a 
solution of zinc chloride, or with a mixture of 240 grammes zinc 
sulphate and 120 grammes salt dissolved in a pail of water. Com- 
mercial zinc salts cannot be used, as the presence of iron salts causes 
them to produce stains on linen. 

In Hospitals special precautions are obviously necessary, and it is 
natural to expect in them the most improved methods of disinfection. 
Most of the larger hospitals in England are now fully equipped with 
modern steam disinfecting plant for bed-linen, clothes, and the like, 
and, in one or two, special cremating apparatus are in operation for 
the destruction of infectious stools, bandages, dressings, and valueless 
articles. The floors of the wards are preferably of polished wood, and 
they and the walls near the beds may be mopped with 1 in 20 carbolic 
acid solution from time to time. The bedstead and bedding may be 
conveniently disinfected by sulphurous acid, and the smaller wards 
may also be disinfected by this gas. Carbolic acid, 1 in 20, can be 
used in bed pans, spittoons, and other dejecta receptacles. For 
surgical dressings, diluted liquor soda chlorinate or carbolic acid 
* Arch, f. Hygiene, vol. xv., p. 55. 


(1 in 40) are generally employed. Eucalyptol is still frequently used 
in bronchitis kettles for diphtheria and pulmonary diseases. In the 
operating theatres and obstetric wards mercuric chloride 1 in 1,000 
finds most favour. In London the Metropolitan Asylums Board has 
been constituted a Local Authority under the Diseases Prevention 
Act, 1883 and 1885, and in 1891 its powers were increased so that it 
is enabled to secure accommodation for cholera patients in the event 
of an outbreak. The arrangements in 1892 provided for 1,700 beds, 
not including 250 available at the Board's Hospitals. These cholera 
beds were secured partly by the acquisition of sites for temporary 
huts, and partly by special arrangements made with the larger hospitals, 
infirmaries, and workhouses. This constitutes the first line of defence 
in London in the event of an outbreak. 

Cisterns for drinking water must not, obviously, be connected with 
the water-closet tanks. They must be occasionally scrubbed out, every 
three or six months, according to the quality of the water. If made 
of lead, care should be taken not to expose the metallic surface, or 
lead may get into the water. If any foul deposit, or confervse, have 
collected on the sides, the cistern should be brushed over repeatedly 
with a solution conta,ining 5 per cent, permanganate crystals and 5 
per cent, sulphuric acid. Householders can have a quart of this 
solution made up at a chemist's (water 1 quart, potassium perman- 
ganate crystals 2 ounces, sulphuric acid 2 fluid ounces ; cost about 
6d.). The solution should be used till the pink colour of the perman- 
ganate remains for an hour, then it should be well flushed till all colour 
has been removed. A slight brown coating of peroxide of manganese 
on the walls will be advantageous, by serving as an oxidiser, and 
preventing further growth. Several inventions have been introduced 
for allowing a small quantity of permanganate solution to be constantly 
admixed with the water, but any admixture of a chemical, except a 
minute quantity of slaked lime, properly used as in Clark's process 
(p. 15) would be injurious; they are, however, of service in small 
cisterns used for closets and urinals. One of these inventions places 
the crystals in a horizontal bottle with a narrow tube, another in 
tablets,* a third is a closed porous pot hung in the cistern.f Straling's 
sanitary tube is somewhat similar. When a rain supply is used for 
drinking in cottages in remote parts, care must be taken that the 
water-butts are kept very clean. Iron tanks are better than wooden 

Water-Closets should be of modern patterns, admitting of washing, 
flushing, and proper cleaning of walls and pans. The walls should be 
of cemented tiles or lime-washed. The solution of acid permanganate 

♦ Symonds, Patent No. 8,351, 1885. t Austin, Patent No. 4,981, 1885. 


should be used occasionally to cleanse the pans. Chloride of lime' 
should not be used, as it corrodes the metal fittings, and has often 
caused serious mischief by eating holes in lead or iron siphon traps. 
Mercuric chloride also corrodes lead pipes. The flush of water at each 
using should be preferably 3 gallons. A valve closet, though rather 
expensive, seems to be the best form for indoor use. 

Earth-Closets are daily diminishing in number, owing to the fact 
that the rapid and inoffensive removal of excreta is most economi- 
cally efiected by the water-carriage system. The mass of water with 
which each excretal mass is mixed, the perpetual movement of water 
in the sewers, and the low temperature in them, are unfavourable 
to bacterial development. Pathogenic microbes soon die in a mass 
of water owing to their conflict with non-pathogenic microbes and 
perhaps also as the result of other unrecognised factors. The system 
is, however, objectionable, because of its fouling so large a mass of 
water. It is nevertheless a mistake to suppose that faeces pollute 
sewage any more than any other waste matter discharged into the 

It was with the object of saving the manure, as well as the 
immediate disinfection of the faeces, that Moule, in 1863, intro- 
duced the earth-system of closets. Earth is popularly believed to 
be a universal disinfectant, yet it abounds in microbes, some of 
which are pathogenic (Koch). Indeed the very nitrification, upon 
which the purifying action of earth is so largely dependent, is in 
great part due to the life and growth of microbes. The earth should 
be dried or, preferably, baked before using. In some districts this is 
done every day over the oven ; it could also be baked in larger 
quantities over a baker's oven or in a special furnace. So dried the 
earth is very absorbent, and instantly removes all odour when only 
a light covering is spread over the excrement. But its effective 
use is ruined by the discharge of urine at the same time ; if this 
could be kept separate and used for agriculture, the process would 
be excellent. Unfortunately the manure is of hardly any value, 
on account of the rapid loss of ammonia. Dr. Rolleston showed that 
as the earth became damp, this gas was evolved. Success depends 
more on the quality than on the quantity of earth. Sand and gravel 
are inert, chalk feeble and dry clay good, whilst garden soil, loam, and 
peat give the best results;* 2 lbs. of dried earth at least are required 
for each evacuation. At Wimbledon camp in 1869, when 140 tons 
of dry earth were used in a fortnight for 30 tons of excreta the 
deodorisation was complete.! Green and white moulds destroy the 
faecal matter, and in 5 or 6 weeks it is undistinguishable from 
* Bnchanan and Radcliffe, Heport of 1869. t Lance(, July 24, 1869. 


ordinary earth, so that it can be safely spread on gardens or on 
land, provided that it is ploughed or dug in. Although of so little 
manurial value, containing only about O'l per cent, of nitrogen and 
0*5 per cent, of phosphoric acid, it has been found beneficial for 
soils. Although pathogenic organisms are not killed by the process, 
they do not in jiractice escape, and there is no record of epidemics 
having been caused. For places without a copious water supply, this 
system is better than pails, and much superior to privies. Dr. Poore 
has recently advocated an earth system for rural sanitation. 

The Goux-Thulasne Method is a combination of the earth and the 
pail systems. In an iron barrel with handles a slightly conical core is 
held, and the intervening space packed with dry earth or a pulver- 
ulent disinfectant. When the core is withdrawn, a cavity of the same 
shape is left. These are carried round on a dray and left at the houses. 
At the end of a few days they are collected, shaken so as to cover the 
exTcreta with powder, and covered with an air-tight iron lid before 
removal. They must be kept from the rain. There should be urinals 
in the neighbourhood, or a funnel can be arranged in the front part of 
the closet opening to collect the urine separately, so that the earth or 
powder is not wetted. This is an excellent mode of disinfection of 
fjecal matters, especially in sick rooms when the excreta must remain 
all night in the room. 

A Self-acting Earth-Closet has an upright box at the back containing 
the dry earth, &c. By a rack-work and lever worked by a handle in 
the ordinary water-closet fashion, a valve at the bottom of the box is 
opened, allowing a certain quantity of earth to fall on the fseces at 
each evacuation. The receptacle is a large ordinary zinc pail. Or the 
arrangement may be made automatic by a hinged seat. By Norris's 
patent,* the solids are separated by a grating and mixed with earth, 
the liquid portions pass down the drain, which is ventilated by a 
current of fresh air and connected with an ordinary ventilating shaft. 

Pail System. — In villages and some towns on the Continent the 
excreta are discharged into pails, which are collected at night-time, 
and the contents, with or without a perfunctory disinfection, emptied 
into ditches or pits, which when full are covered up with earth. 
From this primitive and dangerous practice, the material has come to 
be called night-soil. Even this is, however, preferable to the old 
system still surviving in English country districts, and even improperly 
permitted in some towns (but not in London) — namely, that of 

Privies, wherein the fseces and urine fall into a brick well, which is 
cleared out at intervals. The soil is infiltrated, and the infected 
drainage has often peneti-ated for years into wells used for drinking 

* No. 20J26, 1S91. 


water, and has been the cause of numerous epidemics. At Rochdale 
an improved pail system is giving good results. The excreta and 
ashes are collected separately and the former converted into dry 
manure, whilst the latter yields fuel for a refuse destructor and steam 

Cesspools can only be dealt with by pumping out the contents and 
distributing them over land. They cannot, obviously, be disinfected. 

S. von Gerloczy,t in an investigation of disinfectants at the Pesth 
Hygienic Institute, found that a practical disinfection of night-soil 
was all but impossible. Even 2^ per cent, of mercuric chloride was 
insufficient to render it germ-free (costing £9, 10s. per cubic yard). 
Complete disinfection resulted when 4 per cent, of cupric sulphate was 
used, but the cost of it would also be prohibitive. In sewage matter 
1 per mille of copper sulphate destroyed all germs and rendered it 
clear and inodorous. 

According to the model bye-laws of the Local Government Board, 
the occupier of any premises shall cleanse every earth-closet on his 
premises, or fixed receptacle, at least once every three months (this 
interval is found sufficient for sanitary purposes, as under the proper 
use of dry earth the stools and even the paper become disintegrated 
and disappear without foetor in the compost — Newsholme) ; those with 
a movable receptacle at least once a week (so that the pails may be 
manageable during scavenging) ; privies and ashpits once a week ; and 
cesspools every three months ; and that between 6 and 8.30 a.m. in 
summer, and 7 and 9.30 a.m, in winter. 

One of the great dangers of leaving faecal matter exposed is the 
visits of flies. The bacteria of tubercle, splenic fever, typhus, and 
European cholera pass through the digestive organs of flies, and re- 
appear in their excrements with unabated virulence. J They are also 
carried adhering to the feet and legs of these and other insects. A 
covering of chloride of lime or of a coal-tar powder has the merit of 
keeping them away. There is a vast number of patents having for 
their object the introduction of disinfectants into the pan or into the 
flush water of closets. Cakes of naphthalene, tablets of plaster of 
Paris mixed with manganate or permanganate, zinc sulphate, thymol, 
&c., are of little value. Automatic distributors designed to keep the 
drains flushed with liquid disinfectants give better results. The 
construction of Jeyes' model is easily understood from the appended 

The contrivance is filled by removing the screw seen in the front, 

* Joum. Soc. Chem. Ind., 1895, p. 340. 

t Deutsche Vierteljahreab. 6ff. Oesund., 1889, p. 433. 

t Centralblatt/. BacierioL, 1888, vol. iv., p. 486. 



then filling the receiver. After the screw has been tightly replaced, 
the machine is raised to a vertical position and suspended inside the 
water waste-preventor in the water-closet. On the water rising, the 
ball acts on the lever, moving the 
plug, which pressing into the well, 
as is seen in the figure, expels the 
fluid in the trough, which falls 
over the sides and mixes with the 
waste water. Each discharge of 
water from the cistern, followed by 
its refilling, automatically mixes a 
portion of the fluid with the water 
for use. Panario* and Skudderf 
have also invented similar con- 
trivances. In the latter the flush 
passes through a perforated tube 
containing the disinfectant in the 
upper portion. Similar devices for 
automatically discharging perman- 
ganate have been proposed (see 
under Cisterns, p. 237). To con- 
tinually supply sufficient of a dis- 
infectant to a closet would, however, 
be very expensive. 

Sanitary officers must proceed 
with caution in disinfecting private 
dwellings, and must give proper 
notice, as it has been proved that 

an action for damages can be maintained unless the disinfection is 
legally carried out. J 

Streets are watered and cleansed by the Vestries and Local Boards. 
It is important to remove refuse and animal excreta immediately, as the 
surface, even when paved, is porous, and the soil is a very favourable 
nidus for the growth of micro-organisms, which escape in the dust 
(p. 223). Mixing disinfectants with the water in the carts is of 
doubtful utility, as the chemical must be much diluted, and the area 
to be covered is often large. It is of course impossible to disinfect 
the open air. Such a procedure may perhaps ofier a certain restraining 
influence on the microbes, but, as ordinarily done, it is often a waste 
of public money. The main work must be done in houses, and in 
narrow streets and courts. It would be better if these latter were 

* Patent No. 4,287, 1891. t Patent No. 10,301, 1885. 

t For particulars of such a case at Filey see Lancet, April 10, 1880. 


Fig. 22. — Jeyes' Automatic Dis- 
infectant Distributor. 


paved with asphalt or some similar non-porous material. An asphalt 
pavement made properly is aseptic, and to a certain extent antiseptic. 
For disinfecting courts and streets a distributor like Bishop's or the 
Equifax sprayers (p. 235) would be of service. The former consists 
of an ordinary rose-jet capable of attachment to an india-rubber hose 
or to the cock of the water supply. A vessel at the side holds a 
supply of disinfectant, which is drawn through a tube into the current 
of water and ejected in spray through the rose. By measuring the 
relative volumes of water and disinfectant passing through in a given 
time and regulating the stopcocks, a perfect mixture in any required 
proportions can be delivered. It is usually made to work with 1 in 
40, 1 in 80, or 1 in 160, by marks on the top, which can be set by 
a key. Such an arrangement is also well adapted for urinals, ships,, 
stables, &c. 

Corrosive disinfectants, such as acids or chloride of lime, could not 
be used with this apparatus. The most suitable would be one of th& 
cresol or pine-oil class (see p. 160 et seq). 

Wood Paving, although it is cleaner than macadam, and less danger- 
ous to horses than asphalt, has been seriously objected to for sanitary 
reasons by Mr. Isaacs.* The same view is taken by Mr. Morgan in 
a recent report to the Liverpool Engineering Society. As the blocks 
are almost non-porous, and do not readily decay, the objection to their 
use is not general ; no increase of illness itt wood-paved as compared 
with other districts has been noticed.! A creosoted wood paving is 
now largely used. J. Tottrell % proposes to mix disinfectants, such as 
carbolic acid, carbolates, sulphites, or bleaching powder, with the 
ordinary cements employed in paving roads, basements, walls, &c. 
The cost would be immense, and the utility seems doubtful. 

Urinals require somewhat different treatment, on account of the 
deposit (containing Bacterium urece and other organisms) which forms 
from the urine and promotes ammoniacal fermentation. Their sides 
should be made of slate, or of enamelled, not painted, iron; then they 
can at intervals be washed down with a solution of sulphuric acid 
2i per cent., and permanganate 2 per cent.; this, of course, must not 
be put into metal pails unless they are tarred. The sides have been 
sometimes constructed of glass, but they are too liable to fracture, and 
then the urine penetrates, and putrefies at the back. Well-tarred iron 
is the next best material, but is easily scratched, and then rusts into 

One form of urinal-cakes consists of sulphates of copper, iron, zinc, 
and soda, with some alum, heated with resin, and pressed. They 

* Q. J. San. Institute, June, 1894. t Lancet, July, 1894. 

J Patent No. 8,317, 1884. 


absorb ammonia, and are, of course, locally disinfectant, but would not 
supersede cleanliness and the process just mentioned. Naphthalene 
tablets are almost useless (p. 148). Disinfecting powders are only 
temporary in their action. 

Stables, pig-styes, and cowsheds require to be regularly cleaned, 
and to be periodically disinfected, like rooms, with removal of the 
animals, to prevent disease occurring. Some varieties of antiseptic 
litter have already been mentioned (p. 12). It is of little use to be 
perpetually deodorising with powders. Dryness, ventilation, and 
cleanliness are better safegiiards. 

For Cattle Markets and Fairs a cresol disinfectant is probably the 
best. A description of the chief ones is given at p. 165. 

Slaughter-houses are pai-ticularly difficult to disinfect on account of 
the large amount of albuminoid matters present. It has already been 
noted that it is almost impossible to sterilise blood. Mercuric chloride 
cannot be used because of its action on albumen (p. 137). Phenol is 
inapplicable for the same reason. Copper sulphate is one of the most 
useful agents in these places. Chlorine and sulphurous acids are 
rarely to be recommended. Cleanliness and rapid removal of offal are 
the first consideratioi\s. Cunliffe and Barlow * subject the refuse to 
heat and destructive distillation. Wood charcoal only serves to 
deodorise, and does not destroy. Slaughter-houses for infected or 
suspected animals are usually situated near seaports, and require 
special methods of isolation, and extra precautionary measures to be 

Bakehouses. — There has been much agitation lately with reference 
to their insanitary condition. Under the Factory and Workshops 
Act, 1891, local authorities have power to act, but the recommenda- 
tions of the London County Council on the bill of 1894 have not yet 
become law. 

Dairies and the Milk Trade will be alluded to under Food, p. 272. 

Pigeon and Fowl Houses, Rabbit Hutches, &c., often become very 
offensive, and are dangerous breeding houses of disease. Legislation 
with regard to them is difficult and hazardous, but at least more 
attention should be given to secure that, especially in crowded 
neiglibourhoods, they are kept in a sanitary condition. They should 
occasionally be disinfected with sulphurous acid, the animals being 
removed. This is only a partial precaution, as their feathers and hair 
are likely sources of infection. Some effect is produced by dusting 
them with flowers of sulphui*. Poisonous disinfectants obviously cannot 
be used. 

Cats, from their prowling habits, have been proved to frequently 
* Patent No. 19,967, 1890. 


carry infection, especially of diphtheria. Dogs are more easily kept 
clean. Rats, as coming from the^ewers, and even mice, are sources of 
infectious danger. 

Vehicles. — The following is from the Report of the Society of Medical 
Officers of Health^ Nov. 19, 1886, on a communication addressed by 
the Commissioner of Police to the Metropolitan Sanitary Authorities. 
In cases of supposed infection. Sanitary Inspectors are authorised to 
disinfect without charge, and give a certificate. " I hereby certify 
that cab . . . has been this day disinfected by me after the manner 
prescribed by the Medical Officer of Health. Signed . . ." 

The cushions, and as much of the internal fittings as are movable, 
should be taken out and put in a disinfecting oven, where such is 
available. If not, they are well beaten and dusted, returned, and 
placed on end so as to expose both surfaces to disinfection. All 
exposed woodwork is washed with carbolic soap, and carbolated oil is 
smeared over metal work with the view of disinfecting it and also 
protecting it from chlorine. The chlorine is evolved inside (see p. 57), 
and the vehicle shut and left so for an hour. 

A process was patented for enclosing vehicles in a kind of chamber 
made of tarpaulin, and then injecting steam or disinfecting spray, but 
it does not seem to have come into use, being cumbrous and expensive.* 

Skins, furs, wool, and hair are constant sources of infection. Wool- 
sorter's disease, anthrax, charbon, and splenic fever, was many years 
ago proved by Pasteur to be due to Bacillus anthracis. Machines are 
now devised for carrying the dust away by fans, and for disinfecting 
by steam ; the trouble is, that the wool will not bear a temperature 
sufficient to kill the anthrax spores, which are, moreover, very highly 
resistant to chemical agents (see Mercuric cJdoride, p. 136). So that 
the only means practicable are cleanliness on the part of the workmen 
and the use of fans. Arsenic is used in the preparation of furs and 
skins, but of the chemical disinfectants, formalin seems to be the 
most suitable for general disinfection of such articles. 

Rags are exceedingly dangerous, because they often come from fever- 
stricken districts, and convey bacteria as well as vermin. Their 
importation in cholera times is generally prohibited, but as they carry 
other diseases besides cholera, they are at all times to be regarded 
with suspicion. It is difficult for steam or heat to penetrate the tight 
bales into which they are compressed by hydraulic pressure. 

Parker and Blackman f force hollow screws into the bales by means 

of suitable machinery, and then introduce a disinfectant through the 

screws, and afterwards air, which displaces any noxious smell. This 

apparatus is used in America. An improved process has been devised 

• Patent No. 5,434, 1883. t Patent No. 16,539, 1884. 


by Paton and Ransom.* Conical perforated pipes are first driven into 
the bales, and then hot air is forced into the bales to heat the interior 
and prevent the steam which is subsequently introduced from con- 
densing. Steam at 10 to 25 lbs. to the square inch is then forced in 
for fifteen to twenty minutes, succeeded by hot air for ten minutes to 
remove moisture, and cold air for about the same time to finally cool 
the mass. It is adapted for cotton and textile goods as well as rags. 
The disinfection of rags is now necessary under the new Act of the 
United States Legislature. All rags used for paper-making must, 
prior to shipment, be disinfected by one of the following methods : — 
First, boiling the unbaled rags in water for half an hour ; second, expos^ 
ing them to the action of steam between 100° 0. and 1 15° C. for a similar 
period ; third, exposing them for six hours in an atmosphere of sulphur 
dioxide, made by burning 3 lbs. of sulphur to every 1000 cubic feet of 
space ; fourth, exposing them six hours in an atmosphere containing 
3 per cent, sulphur dioxide gas liberated from liquid sulphur dioxide. 
By the third and fourth methods the rags must not occupy more than 
50 per cent, of the total cubic space. 

Disinfection of Air. — This is impossible except in confined spaces. 
The germs of cholera and of a large number of other diseases are 
known not to be carried by air, as an exposure to free oxidation in the 
atmosphere (possibly to ozone in addition to common oxygen) and to 
light soon destroys the majority of bacteria. In still air the organisms 
sooner or later settle, especially if the air is damp and the walls are 
moist. The number of microbes is least in pure external air. It is 
greatest in places where the population is dense and the ventilation 
defective. In inhabited houses the impurity is due to the products of 
combustion and respiration. S. Merkel f states that air expired from 
man and from animals even in a good state of health contains a minute 
quantity of a volatile organic base, poisonous in a free state, but losing 
its toxic effect when combined with acids. Brown Sequard, Arsonval, 
and Wurtz X found that (a) vapour expired is alkaline ; (b) its toxicity 
is not destroyed by heating in a closed retort ; hence they conclude 
that the " esprit de corps" as it has been facetiously termed, has the 
characters of an alkaloid. Animals confined in a space from which 
the carbonic acid produced by respiration is continually removed die 
long before the oxygen is consumed, although nitrogen is not poisonous. 

In inhabited districts the air contains, in addition to micro-organisms, 
fragments of carbon, of hairs, fibres of tissues, particles of starch, pollen 
granules, epithelium, &c. These can be removed by filtration through 
cotton wool, also in great part by passage over damp surfaces, or by 

* Patent No. 7,735, 1894. t Archiv. f. Hyg., vol. xv., p. 1. 

X Acad, des Sciences, Jan., 1888. 


subsidence. Breath is ordinarily free from microbes, and sewer gas 
contains exceedingly few. In both tbese cases the freedom from 
germs is due to the subsidence on the damp surfaces present. 

Prof. Klcbs remarks* that the cause of malaria is probably a specific 
organism. From the air of malai-ial districts aspirated through suit- 
able apparatus he obtained organisms about 0'95 micro-millimetre in 
diameter, capable of producing malarial fever on inoculation. He 
proposes the name Bacillus malarice for them. They are developed in 
the presence of free oxygen, hence are aerobic. The subject has been 
more recently studied at some length by North. In addition to the 
apparatus for the disinfection of air already alluded to, there are a 
vary large number of other inventions, of which the following is a 
summary : — 

For Sewer Gas. — Keelin's apparatus : the air is passed through gas 
furnaces, t Eecent experiments with refuse destructors have, however, 
established the fact that, although a comparatively low temperature is 
sufficient for killing micro-organisms, a temperature of at least 1250° F. 
is essential for entirely destroying any noxious vapours. 

Vaporisers. — 1. In M. Godin's vaporiser the fluids are poured on a 
porous stone on a stand heated by a lamp. J 

2. An inlet ventilator in the wall of a room 6 ft. from the ground ; 
the air entering horizontally is deflected through a short tube into 
a well containing a disinfectant; and the charged air then passes 
upwards into the room.§ 

3. Strips of linen are stretched on a series of frames radiating from 
a central hinge, and are syringed with a disinfectant (or it is simply 
poured on them) so as to expose a large surface. The whole apparatus 
is enclosed in a case for carriage. || 

4. Barlow's exhausting ventilator IT is similar, but contains filters of 
antiseptic wadding, and heating chambers for sterilising the air at 
the outlets. 

5. Bristow Hunt ** draws the ventilated air through a coil heated 
by an ordinary stove. This apparatus is recommended for sewers, 
cesspools, holds of vessels, «fec., but is open to the following objec- 
tions : — (a) If the air passes rapidly, there is danger that the central 
parts of the current will pass without being sterilised, on account of 
the bad conducting qualities of air ; (6) the air so ti'eated is rendered 
unfit to breathe ; (c) the coils, if narrow, become clogged and coated ; 
(d) they are uncertain in action, depending on the working of the 

• Atti della R. Acad, dei Lincei^ vol. vii., 1879. 

t Lancet, 1888, vol. i., p. 486. t Chem. and Drug., vol. xxv., p. 89. 

§ Brit. Med. Juurn., 1889, vol. xi., p. 771. II La7icet, 1889, vol. xi., p. 121. 
IT Patent No. 194, 1878. ** Patent No. 1,321, 1878. 


stove ; (e) if made of firebrick flues or fireclay tubes, instead of iron, 
they are easily broken in stoking, stirring, or cleaning; (/) they have 
been known to cause fires by passing near woodwork. Nevertheless, 
a method of this kind is cleaner, cheaper, and more effectual thau 
any chemical disinfection for constant use. 

6. Water or a disinfecting fluid flows in a thin film over rods or 
metal-gauze tubes into a lower receiving tank from which the liquid 
is pumped up again into an upper receptacle. The air to be purified 
is guided by louvre plates or shutters over the wet surface.* 

7. J. S. Mur t draws the air through revolving drums with opposing 
slots, dipping into disinfecting fluid. 

8. J. F. Johnson I proposes to use a rapidly revolving fan which, by 
means of peculiar paddles, disperses the disinfectant as spray through 
the current of air. This is a good apparatus where the motive power 
can be obtained. 

9. C. C. Leathers § also by means of a fan draws air through sawdust, 
tow, (fee, impregnated with disinfectant. 

10. W. H. Spencer || suggests the use of an open water-bath carrying 
a porcelain pan containing eucalyptus or other oils which is heated 
by a lamp underneath, and adjustable as to height above the flame. 

11. Mr. W. Key's screen U is formed by stretching thousands of cords 
of suitable material from ceiling to floor, interlaced with horizontal 
copper wires stretched tight so as to form a flat surface like coarse 
cloth. Water trickling down washes the air which passes through the 
minute holes in the screen. Experiments done in a dense fog showed 
that no fog passes through, and that the air thus purified is bright, 
clear, and free from odour. In the case of dust the results were not 
so satisfactory. A non-corrosive disinfectant or deodoriser could be 
added to the water. If all the air could be made to pass through 
such screens in sufficient volume, it would probably be one of the best 

12. Kingzett** suggests a wick with one end embedded in a block 
of plaster or other absorbent substance, the other dipping into a 
reservoir of a disinfectant so that the evaporating surface is increased. 
This device is also suggested as a means of supplying liquids to 
surgical dressings or bandages. 

Water for drinking and cooking is in London and several large 
towns supplied of very indifferent quality. As obtained from deep 
wells it has been naturally filtered, is free from germs, and almost 

* J. Stanley, Patent No. 3,705, 1880. + Patent No. 2,781, 188.3. 

t Patent No. 5,379, 1883. § Patent No. 22,258, 1881. 

II Patent No. 8,629, 1891. TT Hygiene, May 13, 1893. 
** Patent No. 3,830, 1893. 

248 - 


devoid of organic nitrogenous matter (which has been oxidised into 
nitrates), but is of considerable hardness. River water is stored in 
settling tanks, where, by oxidatfon and subsidence, the microbes are 
mostly removed (see p. 15) ; then it is filtered by two methods — 

(1) Natural filtration ; large reservoirs are dug parallel with the 
banks of the river, being filtered through the ground in transit. 

(2) Artificial filter beds, composed of layers of sand, gravel, and stones, 
through which the water passes into the mains. In most districts it 
is intermittently delivered into house cisterns ; some have a constant 
supply (see p. 237). 

feit/jifi/^ ?* !' 

Fig. 23.— The Equifex Water Heat-steriliser. 

Occasionally the water supplied is turbid, showing that the filter- 
beds are not acting properly; it always contains micro-organisms, 
greatly reduced in number, and usually non-pathogenic. It may also 
be contaminated on its way to the consumer, from the ground through 
leaky joints in the pipes (even full pipes carrying a current of water 
will draw in surface drainage from the soil) or from the atmosphere 
in the cisterns. Absolute safety can only be attained by boiling, or 
by filtration through a Pasteur-Chamberland filter. A temperature 
of 100° 0. does not kill all the germs {Tyndall, Koch, and others) 
unless continued for a long time; hence it has been proposed to 
sterilise water by heating under pressure.* 

* Society Geneste, Herscher & Co., Paris. J. Y. Johnson's Patent No. 2,051, 
Feb., 1891. Also J. Soc. Chem. Ind., May 31, 1892. 


Under the name of Equifex water heat-sterilisers, the Geneste- 
Herscher patent has been recently introduced into this country. It 
is shown in Fig. 23, and continuously sterilises water, and cannot 
work unless the temperature for which it is set is applied for the 
necessary time. 

This control is effected by means of a valve which only lifts and 
permits the passage of sterilised water at the necessary pressure and 
temperature. The sterilising vessel is kept for fifteen minutes at the 
required temperature, and by means of a cock the discharge pipe is 
then opened. The capacity of the sterilising vessel and its discharge 
orifice, and the pressure for which the safety valve is set, determine 
the minimum time in which the vessel can empty itself; and the 
control valve ensures that no part of this time can be occupied in 
passing water below the desired temperature. 

By allowing the sterilised water to heat the incoming water, 
economy is effected, and the sterilised water may be delivered within 
2" to 3° C. of the temperature of the service water. The high pressure 
at the same time prevents the loss of dissolved gases, except in so far 
as they re-act with dissolved organic matter on the water, and reduces 
to some extent the precipitation of dissolved salts. The sterilised 
water is passed through sand, and is discharged from the apparatus 
cool. The course taken by the water is shown in the diagram, in 
which the feathered arrows represent sterilised, and the others un- 
sterilised, water. 

The form shown in the diagram is that of an apparatus used in the 
operating rooms of hospitals, and supplying about 8 gallons cold and 
8 gallons hot sterilised water per hour. When heated by gas it 
consumes about 45 cubic feet of gas per hour. 

KUhn of Paris uses a similar sterilising plant for beer and other 
organic liquids.* 

Boiled water is not palatable ; filtration afterwards aerates it and 
restores the proper taste ; hence, as it is proved that boiling does not 
completely sterilise, boiling first and filtration afterwards through a 
good and clean filter may be recommended. Water after boiling must 
be kept in very clean vessels, and should not be exposed to air long 
before drinking, as the multiplication of bacteria goes on far more 
rapidly even than in unboiled water. f Boiled water may be artificially 
aerated with carbonic acid in a gazogene apparatus. Dr. Altehoefer's 
suggestions as to the use of hydrogen peroxide have been already referred 
to (p. 85). Water in cisterns with constant supply lying stagnant 
while families are away for the holidays may be a source of danger. 

• Joum. Soc. Chem. Ind., 1894, p. 1133. 

t Miquel, Analyse Bad&rioL des Eatix, Paris, 1891, p. 146. 


The recent report of the Royal Commission on Metropolitan Water 
Supply (1893) has drawn attention to the present unsatisfactory nature 
of our bacteriological knowledge of river waters. Although there are 
abundant opportunity for pathogenic organisms to enter the Thames, 
hitherto investigators have failed to detect their presence in the water 
supplied by the London companies. This result may be partially due 
to the filtration which the water receives, but is probably mainly to 
be attributed to their rapid attenuation and death when introduced 
into a river water containing numerous non-pathogenic organisms. 
It must not, however, be forgotten that the fate of these pathogenic 
organisms has not been properly studied, and it is quite possible that 
they may be present in such filtered water in a modified form, and 
capable of giving rise to the original pathogenic forms so soon as they 
are brought into a suitable medium. It seems, therefore, essential 
that adequate precautionary methods of boiling and filtration should 
be adopted by householders in towns possessing a river-water supply, 
especially in warm weather and when there are any indications of 
epidemic disease. 

Preservation of Timber. — Although not strictly hygienic, attention 
may be drawn to the use of antiseptics for preventing the decay of 
wood. Two methods are in use : in the first, hydraulic pressure is 
employed for injecting the preservative liquid into the lower end of 
the log; in the second, the liquid is drawn in by vacuum pumps at 
the upper end, the logs being encased at the end by india-rubber or 
leather. These processes equally saturate the tissues, if thoroughly 
cai'ried out, with the antiseptic, and prevent the penetration of the 
disintegrating mycelium of fungi such as Merulius lachrymmts (dry 
rot). The first method is the quicker. Either of them presupposes 
the driving or sucking out of the natural juices, and replacement of 
them by the antiseptic solution. Both of them are analogous to the 
injection of corpses by preservatives. 

Copper Sulphate (Kyanizing) was the earliest agent used, and is still 
found eflfectual, although the corrosion by galvanic action of any iron 
nails, screws, or bolts embedded in the wood is a serious disadvantage. 
Mercuric chloride is precluded by the expense. 

Creosote Oils are now commonly used. Well-seasoned timber is 
placed in a vessel so constructed that a more or less perfect vacuum 
can be obtained by an air-pump. The creosote oil, previously heated 
from 35° to 50° C, is allowed to enter the exhausted receiver, and pres- 
sure is then applied by pumps in order to efiect the better penetration of 
the antiseptic fluid. In S. B. Boulton's improved process, the exhaus- 
tion is continued after the entrance of the creosote, which is heated to 
a temperature somewhat above 100° C. By this method the moisture 


contained in the pores of the wood is volatilised and removed by the 
pump, and the oil subsequently penetrates the wood very thoroughly. 
A great advantage of this process is that wet timber can be at once 
treated without being previously seasoned. The amount of creosote 
oil taken up by the timber varies considerably, but is usually about 
1 gallon per cubic foot of wood. The smell of creosote oil is much 
disliked by the lower animals (white ants, <fec.), while certain of the 
constituents have a powerful antiseptic action. S. B, Eoulton and 
Ooisne, on behalf of the Belgian Government, have proved that in the 
course of a few years the tar-acids (phenol, &c.) in railway sleepers, &c., 
completely disappear by dissolving and by volatilisation, whereas the 
semi-solid constituents, such as naphthalene, and the higher boiling 
oils (above 315° 0.) remained, and could preserve the wood for sixteen 
to thirty-two years.* Hence the phenoloid bodies of high boiling 
point and slight solubility are probably of more value for creosoting 
timber than carbolic or cresylic acids themselves. But the lower 
phenols are doubtless of value in coagulating the organic matter 
present in the sap, and should be present in creosote oils in sufficient 
quantity to effect this. 

* Allen's Commercial Org. Analysis, 1886, vol. xi., p. 552; S. B. Boulton, Froc. 
Inst. Civ. Engineers, M&y, 1884. 




Personal Disinfection : Sachets and Lockets practically useless — Cleansing the 
Hands — Soloids — Gloves — Caustics — Snake-Bites — Burns and Scalds. Disin- 
feotion of Cavities of the Body : (a) By Washing out— (6) By Spray — (c) 
Gargles — (d) Injections of Gases or Vapours — (e) Inhalations. Antiseptic 
Dressings : Sulphocarbolate of Zinc — Salufer Cubes — Sozal — Gauzes and 
Wools — Antiseptic Paper — Rinsing Surgical Instruments. Hypodermic In- 
jections. Antiseptic Soaps : Mouth Washes — Ointments. Respirators : 
"Sanitary Wool" Clothing. Internal Disinfection: Charcoal — Sodium 
sulphethylate — Chlorinated Soda— Oxygen — Sulphides. Internal Antisepsis : 
Phenol — Creosote — Essential Oils — Mineral Waters — Acids — Sulphuric Lem- 
onade — The Vienna Mixture — Betol, &c. — Quinine — Benzosol — Phenosalyl — 
Vaccination. Preservatiox of Food : Causes of Change in Foods — (1) 
Oxidation — (2) Reduction — (3) Metallic Contamination — (4) Organisms — 
Methods of Exclusion of the Latter — Drying — Smoking — Necessity of Proper 
Cooking — Curing by Wood Vinegar — Danger of Poisoning by Stale Fish. 
Infection by Milk : Tyrotoxicon in Cheese, Milk, &c. — Infection of Food 
by Bacteria in Air — Precautions. Preservation by Cold : Does not Kill all 
Bacteria — Downward Draught — Methods of Freezing Meat — Large Refriger- 
ators — Hydrocarbonic System. Preservation by Chemicals : Not Successful 
— Sulphites, &c. Preservation by Heat : Canning Processes — I. Chloride of 
Calcium Process — II. Aberdeen Process — III. Jones' Vacuum Process — IV. 
Salzer's Baltimore Process — V. Budenberg's Steriliser — VI. Hartmann's 
Method. Milk : A Common Vehicle for Contagion — Precautions — Heating 
under Pressure — Preservatives. Condensed Milk : The Anglo-Swiss (Borden) 
Process — Hooker's Cream Milk — Condensed Beer. Butter : Conditions affect- 
ing Rancidity. Cheese : Aseptic Wrappers — Pickling and Cleansing Grain. 
Bread : A Means of carrying Infection. 


Thk "last line of defence" includes the precautions taken by the 
private individual. These may be considered to include cleanliness of 
the home, cleanliness of the person, and purification of the clothing. 
The first and third have been discussed, and it has already been 
pointed out that individual immunity cannot be ensured by carrying 
about the person camphor, aromatic vinegar, eucalyptus, or other 
chemical substances, which in former times found favour as charms, 
since these agents cannot reach an effective proportion in the atmo- 
sphere. Many devices of little value have, however, been patented 
for personal protection in even recent years. Thus Woodthorpe and 


others* suggest an ingenious arrangement like a vesta-box, with a 
sliding perforated case, to be kept in the pocket, and a mixture of 
bran 4 ounces, camphor 1 ounce, eucalyptus oil 2 drachms, hydro- 
naphthol 1 drachm, carried in a linen sac, has been seriously 
recommended to ensure wearers against infection in houses. 

In fever cases it is now generally customary to sterilise the hands 
by washing in a 1 per mille solution of mercuric chloride with a little 
salt and hydrochloric acid (p. 138), and rinsing them with plain water 
before washing with soap. In cases of very great danger the clothes 
are afterwards disinfected by steam. Notwithstanding the fact that 
many other antiseptics have been proposed for the hands, mercuric 
chloride seems still to be the best. A few ounces are quite sufficient, 
and should not be diluted beyond 1 in 1,000. The same solution 
should also be used by nurses and attendants when leaving the room ; 
a convenient way of preparing the solution is to dissolve one " soloid " 
in a pint of water, taking care to stir well till all has dissolved. One 
of the soloids in a pint of water makes a 1 in 1,000 solution. They 
are characteristically coloured and shaped to avoid mistakes. In- 
fectious matter is particularly liable to remain under the nails. 

It is well known that any cut or abrasion of the skin when handling 
septic matter inevitably causes blood-poisoning, which, if not fatal, 
leaves dangerous after-effects ; also that specific diseases can be inocu- 
lated in the same way. Waterproof gloves are manufactured for 
operations involving such risk, but as they very much deaden the 
delicacy of touch, they are seldom used. If a cut or wound has been 
accidentally produced, cauterising with nitrate of silver, nitric acid, 
phenol, permanganate, or osmic acid is frequently recommended, but the 
eschar left is often very painful and troublesome to heal, besides not 
being thoroughly safe against inoculation. Covering with lead or court 
plaster, or with collodion ; painting with iodine or iodoform tincture ; 
thoroughly drying the cut and painting with a solution of Stockholm 
tar or Burgundy pitch in alcohol, ether, or acetone, are among the 
other treatments suggested. None of these methods give absolute 
immunity, so that, in case of accidental puncture during a post-mortem 
or operation, or in handling contagious matter such as dead meat, 
skins, or evacuations, it is probably safest to wash immediately with 
mercuric chloride, dry, and at once cauterise, and thus combine the 
two precautionary measures. "When, unfortunately, the abrasion has 
not been noticed at the time, this treatment should still be resorted to. 
Afterwards, hypodermic injections of an antiseptic have been recom- 
mended, and cinnamic acid, styrol, phenyl-propionic acid, /3-naphthol, 
and betol are used for this purpose ; phenol or any other reagent 
* Patent No. 2,770, 1891. 


which coagulates the blood is of course inapplicable. For ordinary 
bites and scratches similar treatment may be adopted ; the part should 
be afterwards protected by antiseptic gauze or wadding, iodoform 
powder, or, failing these, by lead plaster, an ointment, or flour paste. 

Snake-bites are considered to owe their virulence to an ill-defined 
poison of an albuminoid nature (a " leucomaine," Selmi and others), 
or to the crystalline cobric acid of Blyth. Filtration, which removes 
micro-organisms, does not afiect the potency of snake-venom. Hypo- 
dermic injections of diluted ammonia, after sucking out the poison 
(it is almost inert internally), seems the best remedial treatment. 
Burns and scalds are liable to septic poisoning if the epidermis is 
broken, so that they also should be protected, but not cauterised. 
Wasp-stings and insect-bites have caused death. The best remedies 
are liquor plumbi subacetatis (p. 134) or Goulai'd's extract, and the 
old-fashioned hartshorn and oil. 

Disinfection of Cavities of the Body. — Cavities of the body, such as 
the lungs, larynx, nasal passages, throat, urethra, bladder, and uterus, 
are peculiarly liable to the attacks of microbes, causing inflammatory 
and purulent conditions, and even absorption and specific diseases. 
Several modes of treatment are in use, and have been several times 
alluded to in the chemical section. They may be thus summarised : — 

(a) Washing out by inflow and outflow tiibes with lukewarm water, 
then with a weak solution of an antiseptic, which should not be one 
with a strongly poisonous action on the system. Phenol, resorcin, 
and mercuric chloride have been absorbed with dangerous, and even 
fatal, effects. Iodine is very irritant. lodol has been recommended, 
likewise betol and phenyl-propionic acid.* Salicylic acid is dangerous, 
irritant, and not effective. A solution of silver nitrate in distilled 
water has been tried with great success : the objection to it is that if 
weak (1 in 1,000) it is almost wholly precipitated by the chloride of 
sodium in the fluids of the body, and if stronger (1 in 200) it has on 
some occasions caused sloughing. Sulphocarbolate of zinc, 1 in 1,000, 
has the advantage of being mildly astringent, and seems to be safe. 
A sulphocresylate would probably be still safer, and is a stronger 
antiseptic. Alumnol (p. 179) is a useful and powerful astringent. 
Glycerine is irritant to mucous membranes, but it is useful when it is 
necessary to keep surfaces moist. On boric solutions see p. 101. A 
number of the newer antiseptics are advocated for this special branch 
of antisepsis, but they await more extended and impartial surgical 
trials, as many of the earlier statements have not been verified by 
recent experiments. 

(6) Spraying. — Any of the former may be used in the form of spray, 
* Klein, in Stevenson and Murphy's Hygiene, p. 261. 


the advantages being that stronger solutions may be used, that only 
the affected parts are treated, that the irritating and depressant action 
of large volumes of water are avoided, that a local refrigerant effect 
may with safety be produced, that much less of the medicament is 
required, and that the action can be watched, and the process repeated 
with facility and without shock. The various spray-producers nearly 
all act on the same principle ; a current of air is blown by an india- 
rubber ball, with a second ball to render the blast steady, across the 
narrowed orifice of a vertical tube dipping into the liquid in the bottle. 
The strength and fineness of the spray are regulated by the relative- 
size and position of the orifices, and the amount of liquid delivered is 
known by the graduations on the bottle. The use of chlorine water, 
with or without cocaine hydrochloride, has already been alluded to 
(p. 59), and boric sprays are frequently used for the throat. Solutions 
in ether were recommended by Philip Sterne, as far back as 1767,* 
as antiseptic spray. Sprays are much used in Vienna on the ground 
that they more easily penetrate parts covered with hair — e.g., mercuric 
chloride, 1 to 2 per cent,, for mucous membranes, and chrysarobin, 
10 per cent., for mycosis of the skin, f In hooping-cough, 2 per cent, 
resorcinol in water, sprayed on the nose, pharynx, and larynx every 
two hours, is said to give speedy relief. 

(c) Gargles are a form of washing out only applicable to the throat. 
Honey and borax, tannin, and alum have been used from time im- 
memorial. This method is easily used by unskilled persons, but is 
inferior to that of spray, as there is no certainty that the parts affected 
will be reached. It is evident that no drug which will be poisonou» 
if swallowed can be employed. 

(d) Injections of Gases or Vapours. — It is a familiar fact that if 
an abdominal cavity be wounded, septic poisoning and peritonitis is 
almost certain to supervene, and that washing out may be dangerous, 
owing to the intense irritation, and may even cause the above 
disastrous result. In these cases spraying is also interdicted. Life 
has frequently been saved by gaseous injections, and sulphur dioxide 
seems to be the best remedy to employ. This is most readily obtained 
by blowing a current of air through a tube containing some fragments 
of sulphur, and allowing the gas produced to enter the cavity. The 
part of the tube containing the sulphur is heated by a spirit lamp, 
taking care that the end of the tube is kept cool. Blowing air through 
a saturated solution of sulphurous acid or through a mixture of a 
sulphite with acid is inferior to the above, as the quantity delivered 
is uncertain. Liquefied sulphurous acid from a Boakes' bottle cannot 
be used for this purpose, as the cold produced is intense and would 

• Advice to the Consumptive. J Pharm. Jcum., voL xxi., p. 1040. 


produce shock. Unfortunately sulphurous acid, by being absorbed 
into the system, is recorded to haye produced fatal effects in one or 
two cases. Baxter experimented specially on its effect on the virus 
of peritonitis * with favourable results. Chlorine, bromine, and iodine 
vapoui's are irritant and dangerous. Many others, such as chloroform, 
ether, phenol, &c., are excluded by their narcotic action. Iodoform 
vapour has caused poisonous effects. Carbonic acid is very soothing, 
and rapidly subdues inflammation, but for this purpose the gas must 
be thoroughly washed. It is only a feeble antiseptic, but would be a 
better medium for other antiseptics, such as eucalyptol, than air. 

(e) Inhalatiotis. — Chloride of ammonium is beneficial in bronchitis 
and asthma. The simple breathing of the vapour of vinegar and hot 
water also gives relief. Koch proved that a number of essential oils 
when inhaled with steam are inhibitory to tubercle, f 

Antiseptic Dressings usually include cotton-wool, wood-wool, or 
gauze, which act as germ excluders ; they are [kept moist with 
diluted soda chlorinata (p. 63), or with boric acid solution (p. 99) ; 
sometimes phenol 2\ per cent., or mercuric chloride 1 in 1,000, are 
used, but they are liable to produce ill effects on absorption. A large 
number of other preparations have been already described in the 
chemical section. Sulphocarbolate of zinc is one of the best. There 
is a great advantage in changing the agent every few days ; even the 
most innocuous are liable to become irritating if continuously used. 
Diluted cresol and Sanitas fluid are useful in rotation with boric and 
with chlorinated lotions. Glycerine is objectionable. Salufer cubes 
(see Silicojluoride, p. 79) are portable and convenient. One cube 
dissolved in a quart of water is used for dressings, or with a pint of 
water for washing the hands. Sozal, aluminium sulphocarbolate, is a 
strong astringent and antiseptic lotion (p. 158). Diaphtherin (p. 193) 
in 1 per cent, solution has been much used in Germany. Tichborne 
recommends J zinc sulphite as non-poisonous and not irritating. 

Gauzes and Wools are described under iodoform, boric, and salicylic 
acids, and zinc-mercuric cyanide (p. 142). Hydronaphthol gauze (p. 179) 
has recently been much praised. Salicylic gauze is irritating. Thymol 
or eucalyptus gauze would seem to be the best and safest. Benzoated 
gauze, 5 per cent, has also been recommended. 

Mr. Duquaire, of Lyons, has invented an ingenious antiseptic paper. 
The material is asbestos with about 5 per cent, of ordinary paper pulp, 
worked into soft paper and soaked in a petroleum-benzene solution of 
beeswax. The solvent having been evaporated off in the open air, the 

* Appendix to the Report of Med. Off. of the Privy Council, 1875. 
t Marshall Ward, Journ. Soc. Chem. Ind., 1893, p. 943. 
Z Brit. Med. Journ., 1890, p. 1064. 


tissue is ready for use. When required it is set on fire, and is so 
made aseptic, and may be employed at once for dressing wounds.* 

Unfortunately many of the antiseptic wools and dressings met with 
commercially are of uncertain composition, and insufficient attention 
has hitherto been paid to the importance of storing these articles in 
such a way that the antiseptic present shall not be volatilised. 

In France their sale, except by duly qualified pharmacists, is for- 
bidden, but the question does not seem to have been discussed in 

Surgical instruments must be rinsed in a disinfectant which does 
not corrode steel ; the various cresol preparations are much used for 
this purpose. Those that turn turbid with water have the disadvan- 
tage that the instruments cannot be so well seen (see p. 163). A good 
preparation seems to be potassio-mercuric iodide, 1 in 4,000, or two of 
the soloids to a pint, for hands or instruments. 

Antiseptic Hypodermic Injections. — Several of these have been 
much employed recently in France, particularly for phthisis; the 
basis is olive oil, and all the ingredients are carefully sterilised by 
heating to 120° 0. 

Picot uses guaiacol 5, iodoform 1, olive oil to 100 ; Morel-Lavallees' 
solution consists of eucalyptol 12, guaiacol 5, iodoform 4, olive oil 
to 100. 

Also solutions in olive oil of creosote 1 in 15, and eucalyptol 2 to 
4 in 10 have been suggested.! 

A number of mercurial compounds are used specially in syphi- 
litic affections. They have been already enumerated and described 
(p. 143). 

Antiseptic Soaps. — The incorporation of a suitable antiseptic with 
soap has long been recommended by medical men as being a con- 
venient method for ensuring a regular use of an antiseptic. Coal tar 
was one of the earliest materials used in this manner, and coal-tar 
soaps, containing, however, mainly the phenoloid derivatives of tar, are 
frequently employed. At the present time many other bodies are 
utilised. The Sanitas Company since 1888 have incorporated their 
" Sanitas fluid " with an ordinary soap, and advocate this preparation 
for a variety of uses. These soaps are prepared as follows : — Resin or 
crude turpentine is dissolved in alcohol, and sufficient potash added 
to saponify the resin, and to leave an excess to combine with some 
fatty acid which is subsequently added in alcoholic solution. Soap, 
essential oils, or any disinfectant can also be added at the same time, 
and the alcohol recovered for a second operation. 

* Chem. and Drug., 1890, p. 36. 

t Vicario, Amer. Druggist, June 15, 1891. 



The Jeyes' patent covered the use of gas tar from which the light oil 
has been distilled off. To the heavy oil an equal weight of caustic 
soda and twice its weight of cocoanut oil are added, and the mixture 
saponified in a jacketted pan. The addition of rosin, sulphate, and 
carbonate of soda is also provided for, if deemed desirable. Quibell's 
disinfectant soap and powder belong to this class ; they are made from 
a liquid which seems to be a mixture of cresol and pine oil.* Calvert's 
carbolic soap and Wright's coal-tar soap have long been recognised as 
proprietary articles. The manganates have also been suggested for 
rendering soap antiseptic. The salts must be mixed with the cold dry 
soap. They cannot be recommended, as besides being poor disinfec- 
tants, they are liable to leave a brown stain on the hands. 

Eucalyptus, thymol, and terebene soaps are very pleasant prepara- 
tions, and are, of course, antiseptic, but only feebly disinfectant. 
Terebene and glycerine jelly decrease inflammation. Perhaps more 
satisfactory than any of the foregoing are those soaps which contain a 
salt of mercury, of which mercuric iodide is the best (p. 141). It is 
dissolved in potassium iodide, and added to the soap in the proportion 
of from 1 in 10,000 to 1 per cent., according to the purpose. Resorcin 
and salicylic acid soaps are used by Hebra in his clinic at Vienna, and 
are said to be powerfully bactericidal. Max Jolles has recently shown 
that ordinary soaps without any added antiseptic have marked disin- 
fectant properties. 

Mouth washes and Tooth powders. — These are too numerous to be 
discussed here. They are chiefly empirical mixtures which owe their 
reputation to custom or advertisement. Some people use only water 
with a little soap in it to clean the teeth, but it is of advantage to 
assist the friction with a powder, and also to use an antiseptic which 
will penetrate the crevices which cannot be reached by the brush. 
Wood-charcoal powder is excellent, but rather disagreeable. The 
best is said to be Areca nut ; it should not be used constantly, as it is 
apt to scratch and wear away the enamel. Prepared chalk is the best 
foundation for tooth powders, as it neutralises any acid, and being 
softer than the enamel, it polishes but does not scratch. Powdered 
myrrh, Peruvian bark, quinine, and other ingredients are frequently 
added. Honey, borax, varioiis scents, such as orris and rose, are 
among other substances which are commonly found in dentifrices. 
As a mouth wash, where there is decay and the breath is offensive, 
one of the best applications is chlorinated soda diluted to about 
1 per cent., and used occasionally. It is not very pleasant, but it 
removes all odour. Saccharin, sodium bicarbonate, oil of peppermint, 
benzoic and boric acids, tannin, tincture of iodine, and tincture of 
myrrh are also occasionally met with. 

* Lancet, 1889, vol. xi., p. 701. 


Ointments. — With the exception of vaseline, which in itself is 
decidedly somewhat disinfectant, and to a certain extent the prepara- 
tions of glycerine such as " glycerinum saponatum," described at 
p. 227, the bases of ointments are only antiseptic in the sense that 
they exclude air and moulds and bacteria from the surface covered. 
Otherwise their virtues are simply emollient, or depend on the drug, 
such as mercury or zinc, which is incorporated with them. 

G. H. Fox* recommends sulpholeate of sodium as having a remark- 
able power of dissolving antiseptic drugs and of yielding them to the 

Respirators for asthma, &c., are made of thicknesses of silvered 
copper gauze. The air is warmed and filtered before entering the 
lungs. Almost all microbes are removed by the moist sides of the 
little tubes formed by the gauze, which has to be occasionally cleared 
from the dust. Several patents have had for object the introduction 
of a disinfectant into the respirator. Only one that is non-volatile 
would be permissible, as the constant inhalation of any medicated 
vapour would be injurious. Permanganate, charcoal, and various 
tissiies have been tried, but Avithout success, as they obstruct the 
breathing. Every arrangement for filtering air by the action of- the 
lungs must obviously place an additional burden on the muscles of 
respiration, and the supply of air will almost certainly be lessened. 
Hence the use of respirators has become much less frequent. Tyndall 
is credited with suggesting that the human frame should be encased 
in cotton wool to keep out germs. Many of the patents are quite as 
impracticable. Wool clothing comes near to this ideal, permitting 
free egress to perspiration, while excluding dust and microbes. Its 
film of air keeps the body warm, like a respirator. Pasteur, in 1879, 
recommended cotton wool respirators for doctors and attendants in 
fever wards, in the same way that Alphonse Guerin in France, and 
Lister in England, protect wounds. 

Internal Disinfection. — In the alimentary canal, and sometimes in 
other parts of the body, there are always present large numbers of 
micro-organisms, and it is probable that the process of digestion 
itself may be assisted by certain microbes. Even pathogenic bacilli 
•may enter in limited numbers without producing disease. They 
are not destroyed by the gastric juice, but rarely survive in the 
struggle for existence with the far more numerous non-disease- 
producing organisms. They only produce dangerous results when, 
multiplying beyond control, they penetrate the blood and tissues, 
interfere with nutrition, set up irritation by their presence, or poison 
the system by their products of excretion. If they are present 
* Therapeutic Gazette, 1891. 


largely in food, water, or air, it is impossible to exclude them from the 
body, and equally impossible to kill them when they have entered, 
since, as has been insisted on before, any chemical agent of suflicient 
power to destroy the germs would also be noxious, or might even be 
fatal, to the higher animal. All disinfectants must necessarily be 
more or less poisonous. 

The removal of bacteria may, however, be brought about by hasten- 
ing their elimination by purgatives, or by entangling them and their 
products by inert substances like wood-charcoal, which is known to 
have proved most beneficial in indigestion and flatulency, states which 
are probably due to, or at least intensified by, organisms promoting 
abnormal fermentations. Charcoal biscuits are not so efiectual as a 
large dose of fresh charcoal in water. Opinions difier as to whether 
bacteria are eliminated by the skin in profuse perspiration ; there is 
no doubt that the latter frequently gives great relief in fevers, &c. 
Saline purgatives are specially indicated. One of the best for this 
special purpose is sodium sulphethylate, which has been much used in 
Prance, but rarely in England. The alcohol basis which it contains 
renders it slightly stimulant and antiseptic. It is distinctly worthy 
of an extended trial. 

It has been hoped that oxidising agents like chlorinated soda, 
peroxide of hydrogen, potassium permanganate, and even potassium 
•chlorate would be capable of attacking bacteria in the alimentary 
canal. But the last-mentioned passes right through the system into 
the urine without change, while the others not only disturb digestion, 
but are rapidly used up by the easily oxidisable organic matters 
present — i.e., they act on the food before afiecting the far more stable 
bacteria. Much was expected from hydrogen peroxide, but results 
have been disappointing. An oxygenated milk, also an effervescing 
water saturated with the gas under pressure, have also been intro- 
duced, under the idea that the free gases would destroy bacteria. 

Sulphuretted hydrogen water and sulphites were formerly given 
with the object of destroying organisms. They are unpleasant, dis- 
turb digestion, and do not seem to bring about the desired effect. 

Internal Antisepsis. — Although it is impossible to kill the bacteria 
within the body, it is quite feasible to hinder their growth and the 
development of spores by an inhibitory or antiseptic treatment, and 
so at the same time to lessen their irritant and poisonous action. If 
the contents of the stomach were undergoing fermentation by the 
action of yeast, &c., it would be quite possible to stop the process by 
means of phenol, creosote, or an essential oil, with a dose so small as 
not to injure the coats of the stomach. But the same dose would also 
stop or at least impede salivary, pancreatic, and gastric digestions. 


Therefore these powerful agents, though occasionally given in capsules, 
are not in general favour. It has been suggested in a previous chapter 
that the use of condiments such as salt, vinegar, pepper, mustard, and 
spices is really an instinct founded on their antiseptic action, since 
many animals resemble man in this respect. The effect of mineral 
waters, too, depends in a large measure on the antiseptic action of 
carbonic acid, and not on the alkali, since soda water generally does 
not contain soda. 

It has been already pointed out that acids are antagonistic to most 
bacteria (p. 69). Dilute sulphuric acid has been preferred in many 
diseases, especially cholera, on account of the additional advantage of 
its astringent action. Sulphuric lemonade, made by the addition of 
the acid, which should be perfectly pure, to sweetened and sterilised 
■water in quantities sufficient to give a marked, but pleasant, acidulous 
flavour, may be employed freely, and according to all experience with 
much benefit. Dr. Waller Lewis, the late General Medical Officer of 
the Post Office, attributed excellent effects to the habitual and free 
supply of a pleasant-flavoured sulphuric orangeade among the employes 
of the Post Office during several cholera seasons. It is cheap and 
innocuous, and is vefy likely to do much good. Although ordinary 
lemonade contains citric acid, it is more costly, and is inferior to 
sulphuric for this special purpose. 

The Vienna mixture for choleraic diarrhoea consists of 15 drops of 
aromatic sulphuric acid (sulphuric acid 1 in 12, with rectified spirit, 
cinnamon, and ginger) to 1 ounce of sweetened water ; to this is often 
added, under medical advice, 5 or 10 drops of ether and 5 drops of 
laudanum. The mixture has been much used and highly thought of 
in Austria, Germany, and France, and by the English Local Govern- 
ment Board. 

For intestinal antisepsis neither phenol nor creosote can be em- 
ployed, being too poisonous and irritating. Betol, however (p. 179), 
has been successfully used, the ]8-naphthol produced by its decom- 
position being comparatively non-injurious. Resorcinol, thymol, and 
sodium benzoate are sometimes used as internal antiseptics, but they 
have mostly the same objection to their use as phenol. Sodium 
sulphocarbolate (p. 158), on the other hand, is safe and is much 

Quinine and its source, cinchona bark, probably owe a great deal of 
their power in fevers to their antiseptic action. None of the substi- 
tutes for quinine are equal to it in general utility, and many of them, 
such as kairine, have proved very dangerous. 

Several of the derivatives of guaiacol, such as benzosol, have been 
highly recommended, and are described under their respective heads. 


Pheno-salyl (p. 200) is a good preparation for washing out the bladder 
and urethra. 

Vaccination. — Vaccination and other preventive measures of inocu- 
lation are at present foreign to the scope of the present work, but may 
properly be regarded as precautionary measures relating to personal 
disinfection. Modern research seems to indicate that the toxines 
produced by the micro-organisms of infectious disease are the natural 
disinfectants for combating the disease, and there seems good ground 
for believing that progress on these lines will be rapid in the near 
future. The present absence of definite chemical knowledge as to the 
nature of these remedies for phthisis, hydrophobia, diphtheria, and 
similar diseases, renders the subject unsuitable for treatment here, 
although their investigation from a bacteriological point of view has 
yielded, without doubt, some of the most valuable and suggestive 
results obtained in recent years. 

Natural immunity is produced either by dissolved alexines or from 
the resistance of the tissues, whilst acquired immunity is due to the 
presence of modified bacterial products. Roux has shown that the 
serum of animals vaccinated against cholera and pneumonia has no 
antitoxic properties, although it is germicidal on the microbe. With 
diphtheria and tetanus the antitoxin is properly so called, as it is 
destructive to the toxines secreted by the micro-organisms.* 


Among the principal food preservatives are boracic acid (p. 99), 
glycerine (p. 22G), salicylic acid (p. 198), bisulphites (p. 96), carbonic 
acid (p. 104), creosote (p. 161), acetic acid (p. 225), and formaldehyde 
(p. 220). The changes which food substances may undergo before 
consumption may be classified under the following heads : — 

Causes of Change in Food. — 1. By Oxidation. — This is comparatively 
rare and slow in the absence of microbes. Dilute alcohol is trans- 
formed into acetic acid by air when in contact with platinum black, 
but the process is quicker under the action of the vinegar fungus, 
Mycoderma aceti. As far as is known, simple oxidation never renders 
substances injurious. 

2. JBy Reduction. — The only reducing agent that could naturally 
occur in this connection would be sulphuretted hydrogen, which would 
involve putrefaction in the substance or in the neighbourhood, and 
■would therefore presuppose the presence of bacteria. It has been 
suggested that the peculiar taste of certain canned foods depends on 
the reduction of the fluids by the metal, on the ground that its degree 

* Buchner, Amer. Journ. Med.Sci,,J&n., 1895; Roux, Med. Week, Sept. 14, 1894; 
Pagano, Brit. Med. Journ., Dec. 1, 1894. 


is out of proportion with the traces of metal dissolved, and that it is 
caused with such extreme rapidity, as, for example, when an apple or 
fish is cut with a steel knife. In this latter case the taste is often 
imaginar}', as blindfold experiments with apples and fish show that 
the majority of persons are unable to detect which was cut with clean 
steel and which with silvei-. Of course if the metal is allowed time to 
become acted upon, a ferrugiuous taste is imparted. Zinc gives a 
different flavour. Magnesium gives none. Hence the cause would 
seem to be the metal, not reduction. There is no evidence that a 
slight reduction would be at all injurious. Sulphites and formalde- 
hyde, if used for preserving, would cause some reduction in unstable 
constituents of the food. 

3. By Metallic Contamination. — Vegetable substances coming iu 
contact with iron are blackened and their flavour spoilt. This has led 
to the use of copper vessels for preparing jams and syrups ; even 
pickles were formerly made in copper vessels. The employment of 
this metal for vinegar or very acid juices is most reprehensible, as 
even if the surface is clean, an unknown and often considerable amount 
of metal finds its way into the food. Mainly through Dr. Hassal and 
Messrs. Crosse & Blackwell, apparatus of wood, stoneware, and evea 
silver and platinum have displaced copper in making pickles. Enam- 
elled iron should be used for making jams. The presence of copper in 
preserved peas has been defended on the ground that (a) it improved 
the colour ; (h) being antiseptic, it increased the keeping properties ; 
(c) it was not poisonous in small quantities, but acted as a bene- 
ficial tonic. The best authorities regard it as irritant ; it is probably 
cumulative, and it should certainly be prohibited. Lead may be 
present from the solder, and Hehner has drawn attention to the fact 
that almost all canned provisions contain tin in solution. Superior 
goods are put up with oiled paper linings, so as not to come in contact 
with the metal. The irritant efiects of some tinned goods have been 
attributed to chloride of zinc, which had entered in the soldering; 
this, and also the dropping in of particles of solder containing lead, 
have been since prevented by a guard-plate underneath the hole, or 
by the use of resin for soldering instead of zinc chloride. W. Reuss* 
has noticed the presence of lead in preserves contained in tinned- 
iron canisters. The latter were constructed by bending some sheet- 
metal together, thereby avoiding contamination with lead by means 
of solder, and hermetically sealed by india-rubber bands. He subse- 
quently traced the lead to these bands, which owed their colour to red 
lead. On examining red india-rubber bands of French, German, and 
English manufacture, he found them to contain as much as 60 per cent. 
. * Chem. Zeitung, 1891, pp. 1522 and 1583. 


of red lead. Many of the india-rubber bands used for sealing pickles, 
jams, meats, and preserves owe their red colour to sulphide of antimony, 
and are free from lead, but antimony has not been found in the food 
itself. In New York, glass vessels have been tried to overcome these 
difficulties; but, owing to the expense, breakage, and unsightly 
appearance of some forms of soups and meats, have not met v/ith 
much success. For brawn and potted meats earthenware is used. 
Its weight and fragility are the only disadvantages. 

Attempts have been made to coat the inside of the tin with varnish, 
paraffin, &c., but have not been successful. 

If the inside of the tin be much discoloured, or if tinned fruits show 
a strongly marked crystalline appearance on the interior surface they 
are unsafe to be eaten. Any discoloration of the contents, or any 
peculiar odour or taste, should also be distrusted. 

4. By Organisms. — Yeast, moulds, and bacteria of all kinds can be 
carried in the dust of the air, on to the surface of any exposed food. 
There they develop their mycelium, which ramifies throughout the 
substance and accomplishes fermentative and putrefactive changes. 
It would be supposed, therefore, that exclusion of air and dust would 
suffice to preserve changeable bodies. With this object receptacles 
exhausted by an air pump and afterwards hermetically sealed have 
been patented. Pasteur and Tyndall's experiment?, which proved 
that air purified from germs by filtration through cotton-wool caused 
no alteration in urine, beef tea, milk, or sugar solutions, showed 
also that these must be previously collected so as to exclude the 
microbe, or must be sterilised by sufficient heat. It is impossible, 
however, to preserve most alimentary substances in the raw state 
without the addition of spices or chemicals, because the air con- 
tained in them, and the few germs which it is impossible to keep 
out, are sufficient to bring about their decomposition. However, 
eggs can be preserved for months by keeping them in a pan of lime 
water, or by dipping them in a cream of slaked lime and water ; in 
each case the shell is rendered impervious by a coating of carbonate 
of lime, and the albuminous inner lining of the shell is coagulated 
and rendered aseptic, as can be proved by breaking and examining. 
Smearing with fat or varnishing gives a bad flavour. Paraffin wax 
easily peels off", and is expensive. Fruit has been kept from decay by 
a coating of melted wax, when gathered fresh and not quite ripe. 
Jams are usually covered with parchment paper sealed down by white 
of egg. This membrane does not necessarily exclude air, but its tiny 
holes must be small enough to exclude bacteria and spores of mould. 
Generally a disc of tissue paper is laid on the jam, when hot, as 
an additional precaution. It will be found sometimes that mould 


has grown on the top of this, but has not penetrated to the pre- 

Coating with glue, gelatine, or melted fat has been tried for meat 
without success. Meat is preserved to a certain extent by membranes 
such as sausage skins. 

L. Smith, of Chicago,* proposes to store the goods in air-tight vessels 
from which the air can be exhausted, while by a three-way tap 
carbonic acid is admitted in its place. This gas is antiseptic, has 
no eflfect on the foods or containing vessels, and does not alter the 

Drying alone is the subject of a large number of patents, differing 
only in mechanical details. Expression of water and desiccation leave 
the fibre and dried juices incapable of putrefaction, but the flavour 
and digestibility are much impaired. Charqui, South American dried 
beef, and pemmican are well known. Dried vegetables are manufac- 
tured by several firms. Soup-tablets and desiccated soup are generally 
made with vegetables and meat extract, with very little fibre ; many 
of them are wholesome and palatable, and keep well in closed tins. 

Smoking is accomplished properly by hanging up in peat or wood 
smoke. The surface .becomes dried, and also impregnated with acetic 
acid, wood spirit, and creosote. Although the two former eventually 
volatilise from the food, the surface retains a good deal of the 
creosote, and undergoes no change except that the fat in time 
may become rusty or rancid. A great part of this rankness may 
be removed by putting about half a dozen lumps of freshly-burnt, or 
re-heated, charcoal in the water in which the meat is boiled. The 
charcoal removes the odour, but does not thereby render the article 
wholesome, hence the change must not have gone too far. Smoking 
has only a surface preservative action, and does not reach the interior, 
so that the ova of trichina, tapeworm, ic, remain undestroyed. In 
countries like Germany, where smoked sausages are consumed raw, 
or nearly so, the ravages of these parasites are frequently severe. In 
England, where thorough cooking is the rule, such epidemics are very 
rare. Still it must be remembered that neither di'ying, smoking, nor 
salting secures safety against the ova of parasites. To save time, hams, 
haddocks, «kc., are often cured by dipping in pyroligneous acid, or 
crude wood-vinegar, with or without brine, or even by being merely 
brushed over with this solution. Kippers and haddocks are often 
prepared under most unsanitary conditions, and as the treatment is 
often far from complete, may be a source of danger. Very slight 
evidences of decomposition in fish are suflficient to indicate the possi- 
bility of an extremely poisonous] product in the body of the animal, 
• Patent No. 2,444, A, 1891. 


SO that fish must never be trusted in. the same way as high game 
and mutton sometimes are. The faintest trace of decomposition in 
fish forbids its use as an article of food. 

B. Pifiard* prepares an antiseptic liquid by burning wood in a 
suitable furnace and conducting the smoke into a tube or chimney 
through which steam is propelled from a boiler ; the vapours are then 
condensed in a suitable apparatus. The woods employed vary according 
to the nature of the food and the flavour it is required to impart. The 
patentee uses oak for pork, peat for fish, birch for tongues, and so on. 
The length of time during which the food is immersed in the liquor 
varies according to the nature of the article and the strength of the 
antiseptic. When the liquor is of a dark straw colour, the time is 
from three to six days for pork, a few hours for fish, and one minute 
for imported preserved meat, which is thereby much improved in 
flavour and keeping properties. 

It must not be forgotten that as, in the first instance, micro- 
organisms settle on the surface of foods, such food may often present 
a normal appearance, and consequently be passed by inspectors and 
■others as suitable for consumption. 

Milk has been shown to be a frequent source of danger, and many 
epidemics have been traced to its pollution, either through the water 
supply of the cows, carelessness in the dairy, or in the conditions 
obtaining between the time when it is supplied by the farmer and 
■when it reaches the house of the consumer. Vaughan has further 
shown that in addition to the danger of milk containing pathogenic 
organisms, under certain conditions tyrotoxicon, a ptomaine produced 
by a non-pathogenic form, is produced which gives rise to summer and 
infantile cholera. As the poison is destroyed by boiling, its absence 
may be assured by this precaution. Vaughan has also demonstrated 
its presence in cheese, ice creams, and stale fish. 

Cold. — It has already been shown that most micro-organisms are 
not killed by cold. Nevertheless, various methods of refrigeration are 
largely employed for preservative purposes. In Russia and Canada 
carcases are buried in frozen earth from November to May. Fish and 
poultry are constantly brought to town packed in ice. Ships fitted 
with refrigerating apparatus bring meat from Australia and America. 
One of the earlier forms of cooling plant is the downward draught 
method of Kent, in which the cooled air being denser descends from 
the ice-chambers and passes round the meat. It has been found in 
practice that it is not absolutely necessary that the meat should be 
perfectly frozen, a low temperature approaching freezing point is all 
that is required for temporary preservation. In Gamgee's process the 
* Patent No. 21,305, 1891. 


rapid evaporation of sulphurous acid, aided by pumps, produces intense 
cold, circulating by glycerine and water through pipes' Liquid am- 
monia is also used in a similar way. 

At the Victoria Docks there are twenty-one refrigerating chambers, 
holding at times 200,000 carcases of sheep. At Smithfield Market 
the refrigerating space is equal to 250,000 cubic feet, in addition to 
the cold rooms in the basement of the building. The walls and roof 
are insulated by an inch of hair-felt between two thicknesses of deal 
boards joined very closely and with an air-space separating them from 
the building. The floor is rendered a non-conductor of heat by two 
layers of deal separated by a layer of finely-divided charcoal. Re- 
frigerating machinery on the hydrocarbonic system is erected in the 
basement. In this system carbonic acid gas, produced by the com- 
bustion of coal or otherwise, is forced by a pressure of several atmo- 
spheres into cooled water. On removing the pressure by means of 
reversible air pumps the gas escapes rapidly, thereby abstracting heat 
from a reservoir of brine (which stands a low temperature without 
freezing) ; the brine circulates by pipes throughout the building, and 
also cools the inlets of fresh air. The gas is forced again into another 
cooled condenser, and when the excess has been transferred, the 
apparatus is reversed, and the gas escapes back again, cooling another 
reservoir of brine, in the second vessel. By a couple, or a series, of 
these twin vessels, and a system of valves for the brine tubes, the cold 
is kept constant, using the same carbonic acid and the same brine. 
The apparatus is safer in case of leakage or accident than those using 
sulphurous acid and ammonia, and does not involve such high pressures 
as when liquefied carbonic acid is employed. A leak is discovered by 
the hissing sound, or by a light being extinguished when applied. It 
is obvious that in case of emergency the solution of carbonic acid 
could be used like the ordinary fire extincteur. Arrangements are 
provided by which the temperature of the various sections of the 
building may be regulated to requirements, and special precautions 
have been taken for the ventilation of the building, and for changing 
the air very rapidly if need be, so that in the event of a carcase going 
bad from any cause, the risk of its tainting the rest may at once be 

Preservation by Chemicals has not hitherto been successful. Either 
the food has acquired a peculiar flavour, or has lost a great deal of its 
nutriment and digestibility with its juices, as in ordinary salting. 
Sugar-curing aims chiefly at excluding air, as the antiseptic properties 
of sugar are very feeble, but where it is employed for preserving 
jams and candies, it is the heat that is the real agent, since a solution 
of sugar boils at a much higher temperature than water. Protection 


from air is also an effect here, since the viscosity opposes resistance 
to the penetration of germs. Saltpetre, ammonium acetate, acid sul- 
phate of potash, ammonium chloride, lactic, tartaric and citric acids, 
&c., have appeared in several patents, but have not been successful. 
When using these preservatives it is to be noted that (1) if the food 
be directed to be merely dipped, or to have the antiseptic rubbed on, 
so that it can be cut, washed, or rubbed off before cooking, the surface 
only is kept sterile ; (2) if it were possible to permeate the whole mass 
with the antiseptic, the result would be the presence of a quantity of 
the chemical that would certainly be unpalatable and injurious to 
health if frequently consumed. 

Gamgee invented a chemical process to be iised before the death of 
the animal. Having noticed that carbonic oxide when it combined 
with the blood rendered it almost imputrescible, he caused the animal 
to inhale this gas for two minutes. They were thereby rendered 
insensible. After slaughtering, they were hung up in chambers filled 
with the gas (produced by passing carbon dioxide from burning coke 
through layers of red-hot charcoal), and containing boxes of charcoal 
saturated with sulphur dioxide. After twenty-four to forty-eight 
hours' exposure the treated meat kept for many months. The process 
appears to have been unsuccessful on the commercial scale, owing to 
the expense. Injection of various fluids into the veins has been also 
a failure. 

It is said that in the salt mines of Cheshire the atmosphere con- 
taining salt dust preserves the miners against cold, rheumatism, 
neuralgia, and infectious diseases, without being injurious to the 
lungs, and that raw meat will keep for a very long time.* This 
effect may, however, be due to the comparative absence of bacteria 
in still air, as the salt mines are not artificially ventilated. In France 
the use of boric acid, borax, and bisulphate of soda for the preservation 
of food has been adversely reported upon by M. Nocard, and the Seine 
Council of Hygiene have prohibited their use in consequence. 

Preservation by Heat. — The conditions under which heat alone, or 
heat with steam, will sterilise have already been discussed (p. 29). 
Articles of food always contain moisture, so that the conditions 
present here are heat and steam. While the exterior of a joint 
reaches the boiling point, the interior does not attain that tempera- 
ture, so that the germs or ova that may be present are not raised to a 
sterilising temperature. In most canned meats it is probable that the 
whole of the food is raised to the temperature of the water, and, when 
of good quality, they are probably as wholesome, nourishing, and 
digestible as meat that has been cooked in the ordinary way. 
* Manley, Brit. Manuf. Industries, 1878, p. 10. 


M. Appert, of Paris, in 1810, first introduced the process of heating 
provisions in vessels which could be hermetically closed, so that the 
steam should drive out the air and a vacuum be produced. This is 
clearly seen by the fact that the ends of tins which are in proper con- 
dition are concave, that they often collapse, and that there is an inrush 
of air when they are opened. Unless these signs are observed, the tin 
is bad and must not be eaten. All tins are examined in the warehouse, 
and such as are blown, i.e., convex at the ends, owing to gases from 
decomposition inside, are rejected. Collapsed or crushed tins (which 
are sometimes offered cheap) are also dangerous, as in the sharp 
bending of the tin holes are apt to be formed. There are three 
principal processes for canning foods : — 

1. The Chloride of Calcium Process. — The tins after being filled have 
the lids soldered on, leaving a pin-hole for escape of steam. They are 
immersed to two-thirds of their depth in a bath of calcium chloride 
solution, which boils at a higher temperature than water, heated from 
260° to 270° F. for one to three hours, and the hole closed by a drop 
of solder. 

2. The Aberdeen Process. — The tins are placed in a bath as before, 
but they are entirely closed. During the heating they are raised at 
times by a frame, opeiied to let out air and vapour, so that the tin 
does not burst, closed again and the heating continued. This is re- 
peated two or three times, according to the size and substance. The 
pressure within is judged by the forcing out of the ends. Superheated 
steam is used by some firms instead of salt baths ; it is rather more 
difficult to manage, but leaves the tins clean. This process, which is 
known by the tins having two or three blow-holes, presents the advan- 
tage that more of the natural moisture and flavour are retained. It 
has superseded the former process in Scotland, Australia, South 
America, and New Zealand. 

3. Joneses Vacuum Process. — The tins are packed quite full, and 
soldered up except a small hole, with a little quill tube, in the top. 
The bath contains ninety-six 2-lb. tins. Along the centre of the bath 
runs a tube with twelve taps, each of which carries eight stuffing boxes 
connected with the tubes. By a fan or pumps a vacuum is created, 
and the bath is heated gradually to 212° F. The fluid in the tins, 
under the diminished pressure, boils at about 100° F., so that the steam 
and air are carried off" at a low temperature. After a time the exhaust 
taps are turned off. The tins then contain no air, and are full of steam. 
The cooking is continued for two hours at 250° F., letting ofiF the 
steam occasionally as the pressure increases. 

4. Salzer's Baltimore Process. — Meat is subjected to dry steam and 
compressed in moulds, then wrapped in paper or other material, coated 




■with plaster of Paris, embedded in a heated fat such as suet or lard, 
in a can or in metallic foil, with certain precautions.* 

5. In Germany, and to a certain extent in Italy and France, the 
dangerous and objectionable custom is prevalent of eating meat in the 
uncooked state, simply smoked or pickled. Raw hams and bacon only 
smoke-dried, Gotha sausages, and even chopped raw steak with bread 
crumbs and onions are commonly consumed. This practice necessi- 
tates that the meat in the markets should be rigidly inspected, and 
hundreds of carcases are seized and destroyed. With the idea of 
saving this confiscated diseased meat for food, W. Budenberg, of 
Dortmund, has invented a flesh steriliser, in which the disease germs 
are killed by steam under pressure. 

It consists of a large iron cylinder, one end of which opens on hinges 
and closes hermetically against packing. Steam at a pressure of half 
an atmosphere (112° C.) is injected at the top, circulates round the 
movable iron shelves on which the pieces of meat are placed, and 
escapes to a condenser through a tube at the bottom, or can be led 
into a fireplace to burn any unpleasant vapours from the meat. The 
temperature can now be raised to 127° 0. by letting in steam of 2^ 
atmospheres ; after two or three hours' heating all germs of disease 
are destroyed. The fat and liquor are drawn ofi" separately below. 
The fat can be used, the liquor is thrown away. At a higher tempera- 
ture the meat is much disintegrated and dried, but is still digestible 
and fit for the food of animals, dog biscuits, <kc. The temperature of 
the interior of the largest lumps of flesh, as registered by a maximum 
thermometer, remains steady at some degrees over 100° C. The loss 
of weight is from 40 to 50 per cent. 

In some cases, where the apparatus is only used as a meat-steamer 
to save large quantities of meat from being lost by putrefaction in 
summer, it can be worked throughout at half an atmosphere of steam 
pressure. At this lower temperature the meat is as juicy and savoury 
as in ordinary cooking. The interior of the pieces reaches a tem- 
perature of 100° to 120° C, so that it can be sold for eating without 
hesitation. The inventor states that the sterilisation at the higher 
temperature was found by experiment to be perfect. 

6. G. Ilartmann^s process t dispenses with the use of antiseptics, 
and consists of three steps — preliminary sterilisation, germinating 
period, and final sterilisation. The first step consists in subjecting 
the preserves to a temperature of 100° to 120° for a short time; the 
second in keeping them for some days at a temperature of 20° to 30°, 
when any germs which have not been destroyed in the primary 

* Patent No. 11,988, 189'^. t Patent No. 14,601, 1892. 


sterilising process develop. They are then completely destroyed by 
a final sterilisation process. 

7. Process for Preserving Organic Substances hy Formaldehyde. — The 
remarkable antiseptic properties of formaldehyde are said to render 
it a suitable substance to employ. Meat and similar substances are 
immersed for a few seconds in an aqueous solution of formaldehyde, 
liquids are mixed with ^-g-^xnr P^''* ^^ ^*- Solid substances may also 
be exposed to the formaldehyde vapour. Considering the "minute 
quantity employed, there seems not the slightest objection to its use ; 
moreover, meat, vegetables, and similar articles of food, when treated 
with it, do not lose anything of their appearance or freshness, or sufier 
in any other respects. 

Milk. — Bacterium lactis, the organism which turns milk sour, is not 
the only one which finds a favourable place of growth in milk. Infec- 
tion of difierent kinds apparently can be carried by it, and several 
epidemics have been traced to this cause. Hence the strong recom- 
mendations that milk should in all cases be boiled, and that dairies 
should be kept scrupulously clean, and well-ventilated. All cases of 
infectious diseases occurring on the farm must, under heavy penalties, 
be instantly reported, and the supply of milk discontinued until the 
case has been removed and the buildings properly disinfected. Milk 
cans should be washed out as soon as possible after use, and finally 
scalded with boiling water, and turned upside down, in a place free 
from dust, to drain and dry ; then they should be covered till wanted. 
Removing any stale smell by charcoal is not a safe proceeding, as the 
odour is a sign that the cleaning has not been thorough ; in such a 
case the can should be thoroughly steamed, and then washed. Water 
from ponds or contaminated wells should never be used for washing 
vessels that are intended for milk, as this has originated many cases 
of typhoid, scarlet fever, and other zymotic diseases. Strongly smelling 
disinfectants cannot be employed for dairies, since milk is so particu- 
arly absorbent of odours. Probably peroxide of hydrogen would be 
the best agent for this purpose, if it were cheaper. Formaldehyde is 
now largely used in this country and Australia. It is to be regretted 
that jets of steam are not more extensively used for cleaning milk 
vessels ; it would be easy to fit up an apparatus for this treatment at 
railway stations, where the cans could be systematically cleansed before 
going to the farms. 

Milk can be kept for an indefinite time by heating it under pressure 
to 120° C, closing it whilst hot with corks or stoppers, and storing it 
in a jool place. If exposed in a warm situation after this, the casein 
is apt to undergo some molecular change, by which it clots into 
granules, or even sets almost solid, but no putrefaction ensues. It 


does not usually pay to preserve milk ' without concentration, on 
account of the bulk. The usual methods for milk-preservation may 
be divided into two groups — (1) those based on the addition of a 
foreign ingredient ; (2) sterilisation by heat. 

1. Boric and salicylic acids, borax, formaldehyde, cane and milk 
sugars, glucose, sodium carbonate, potassium nitrate, and glycerine 
have been added. Some of these preservatives are obviously likely to 
be prejudicial to the health of young children, and should not be 

2. Bethell in 1848 patented a process for preserving milk, which 
consisted in boiling it to expel all the air, and then saturating with 
carbonic acid ; by this means, milk can be kept fresh for weeks. 

Duclaux kept milk for five years in a vessel from which he had 
previously exhausted the air and heated the contents to 120° 0. 

Sterilised milk is now supplied, in many of the larger towns, in 
bottles which are hermetically sealed. Such sterilised milk is valuable 
for voyages and for invalids. 

In GromAJoaldJs patent sterilising apparatus for fluids f the fluid is 
sterilised in the vessel used for storage ; it can be closed without 
admitting air, and allows the vessel to be filled to any desired height 
without any risk of the fluid being deteriorated, or the bottle bursting 
through an increase of temperature. 

Condensed Milk. — The process was invented by De Leinac in 1852, 
and modified later by Borden of New York, who introduced vacuum 
pans for concentrating the milk without burning. In 1866 the Anglo- 
Swiss Company started Borden's process on a large scale. The milk 
is brought in every morning by farmers, who are kept under very 
careful supervision as to cleanliness of surroundings, and absence of 
disease. It is tested, mixed, and heated in a bath, pure white sugar 
is added, generally beetroot, then run into the vacuum pans (closed 
copper vessels from which the air and steam are exhausted), and 
evaporated rapidly at a low heat for two or three hours, till it is of 
the consistence of honey. 

It has been kept in this way for upwards of twenty years. Great 
cleanliness is of course necessary in the process. The tins must be 
sterilised by scrubbing, then a jet of steam, and finally pure cold water. 
If there be any imperfection in the process, or if the tin be not properly 
sealed, the milk becomes solid and cheesy. If too highly concentrated, 
the milk-sugar crystallises, and the preparation becomes gritty. 

Condensed milk is perfectly wholesome, but the balance of its food- 
value is disturbed by the enormous proportion of sugar, about 50 per 
cent. For this reason it is unsuitable for infants. The directions on 

* See the article on Bor\c acid, p. 99. t Patent No. 1,910, 1890. 



the tin as to dilutions are frequently misleading — 1 in 5 or 6 for 
adults, and 1 in 12 for infants^ras the concentration is only 1 to 3 

A condensed milk containing no added sugar and sterilised in tins 
has recently been introduced. By diluting with twice its volume of 
boiled water a fluid of the composition of ordinary milk is obtained. 

Butter. — The production of sterilised butter has not been entirely 
successful, owing to the fact that the proper sterilisation of the cream 
is prevented by the necessary changing of the receptacles during the 
manufacture. The cream is in consequence brought in contact with 
numerous surfaces, and is necessarily subjected for a considerable 
time to the action of the air. E. E. Ritsert* points out that notwith- 
standing the occurrence of most diverse micro-organisms in rancid fats, 
both aerobic and anaerobic germs die when added to the fresh unde- 
composed fat, from which it is inferred that the change is not initiated 
by them. He also found that xinder the influence of sunlight, which 
killed the germs, the rancidity was produced more rapidly. Experi- 
ments were therefore made with sterilised lard — (1) protected from 
access of air, but exposed to sunlight, to diff'used daylight, and kept in 
the dark; (2) with access of air, exposed to the sunlight, and kept in 
the dark; (3) in atmospheres of moist and dry oxygen, carbonic acid, 
nitrogen, and hydrogen. As a general result it may be stated that 
the result favourable to the production of rancidity proved to be the 
action of light during contact with air, the change being induced the 
more rapidly the more intense the light. Thus it was found that 
sterilised lard, either moist or dry, when kept from contact with air 
in sealed tubes, remained free from rancidity for two months, even 
though exposed to sunlight and warmth. Oxygen, both dry and 
moist, was absorbed freely in the light, the fat becoming strongly 
rancid in one month ; but none was absorbed in the dark, the fat 
remaining quite fresh. Nitrogen and hydrogen were not absorbed in 
any case, and the fat remained unchanged. Carbonic acid was absorbed 
in the light, and to a less extent in the dark, but the lard only acquired 
a tallow-like taste, and no odour. 

G. Mullerf has invented an apparatus by which the whole process 
of butter-making is conducted in the same vessel with the most com- 
plete precautions. The cream is first sterilised by high-pressure steam 
at about 103° 0. Any air which may enter on cooling is sterilised by 
a cotton-wool filter. The churning is then proceeded with in the same 
vessel, the butter-milk being run out at the bottom, sterilised air 
entering at the top. Sterilised water is then added to wash the butter, 
salt and colouring matter (sterilised) is added if desired, and finally 
* Pharm. ZeUung, Sept. 13, 1890, p. 579. t Patent No. 8,264, 1892. 


the butter is churned dry to remove excess of water. The product 
is free from microbes, and will keep for a considerable time. 

Butter that has once been churned cannot be melted without losing 
its character as butter. If sterilised butter from Muller's process 
above could be delivered by a screw pug mill into sterilised tins, so as 
to fill them as nearly as possible, and then soldered up, avoiding 
exposure, the ideal conditions would be fulfilled, and the butter ought 
to keep for an almost unlimited time. It would be free from germs, 
and would be secured from access of either light or oxygen. 

Lactacidine, p. 202, is recommended for butter preservation, to be 
removed by washing before use. Since butter entangles about 10 per 
cent, of water, containing part of the butter-milk which in practice 
cannot be thoroughly removed, and can only be partially preserved by 
salt, no external application — neither this, nor boric, nor even salicylic 
acid — can be depended on. 

Cheese, as is well known, soon undergoes putrefactive changes, 
without apparently rendering it unwholesome. Antiseptic, or, better, 
aseptic, wrappers of close canvas, soaked in boric acid and boroglyceride 
(p. 101) are here of value, and unobjectionable, as the rind is not eaten. 
They may prevent the access of the organism producing ''tyrotoxicon" 
(p. 266), which is the cause of poisonous cheese. 

Wheat and other kinds of grain are subject to the attacks of numerous 
fungi, such as ergot, mildew, etc, which render the flour prepared from 
them unwholesome. The common remedy is to pickle with sulphate 
of copper before sowing. Although the quantity of copper which 
passes into the food is infinitesimal, it would be better if a less poison- 
ous disinfectant could be found. Chloride and acetate of aluminium 
have been well spoken of; they must be used very dilute, say 1 in 500, 
or germination is checked. 

Bread acquires from the air germs of all kinds, and under certain 
conditions becomes poisonous. Hence the use of a covered bread-pan, 
kept scrupulously clean and free from stale crusts, «fec., should be in- 
sisted on. In the early part of 1894 Dr. Waldo drew attention to the 
unsanitary state of London bakehouses. Filth, communication with 
drains, privies in direct proximity, and personal contamination from 
the work-people were discovered in a number of cases. Places where 
the food of the people is prepared should be above ground, in strong 
daylight (the fatal eflfects of light on bacteria have been before men- 
tioned), well-ventilated, and clean. Much more supervision should be 
exercised. It is almost useless to combat bacteria when they are 
allowed to multiply in the daily food. The London County Council 
has issued regulations on the subject, and legislation from Parliament 
is awaited. Dr. Waldo and Mr. Welsh have also shown that organisms 


and their spores are not destroyed by the ordinary proQess of baking. 
By plate cultivation they succeeded in obtaining thirteen different 
species of micro-organisms from the centre of recently baked loaves 
from bakeries in different parts of London. The results show the 
necessity of having proper regulations for bakehouses, as sewage 
pollution of such places would mean that bread might be sent out to 
customers charged with specific organisms. Microbes withstand a long 
exposure to a much higher temperature than that to which the centre 
of the loaf is exposed, without being destroyed, and there is no reason 
to believe that even the greater number of the bacteria in the loaf are 
killed. They also found that tinned and small loaves were often sterile, 
and conclude that the number of bacteria in loaves seemed to bear a 
direct relation to the dirtiness of the bakehouses. It is also important 
that the flour, which undergoes in unsuitable warehouses a rapid 
change, should be kept dry and sterile. Dr. Brown has suggested that 
the use of flour has been the cause of many cases of outbreaks of 
diseases, especially sporadic outbreaks of intestinal complaints. In 
Bristol the number of such cases in the district has directly diminished 
pari passu with the recent activity of sanitary interference with the 
dirty bakehouses of the town. 


Duties of a Medical Officer of Health, and of Sanitary Inspectors. Public Health 
Act, 1875 : Clauses relating to Infection — Hospitals for Infectious Diseases — 
Prevention of Epidemics — Mortuaries — Port Sanitary Authorities. General 
Order of Local Government Board on Cholera, 1883: Regulations as to 
Detention. Dairies, Cowsheds, and Milk Shops Order of 1885: Regu- 
lation of Bakehouses — Housing of the Working Classes Act, 1890 — Public 
Health (Water) Act, 1878 — Vaccination Acts — Burial Regulations — Merchant 
Shipping Acts— Canal Boats Acts — Infectious Diseases (Notification) Act, 1889 
— Infectious Disease (Prevention) Act, 1890. Public Health Amendment 
Act, 1890. Public Health (London) Act, 1891: Rules for Hospitals for 
Infectious Diseases, Local Government Board. Circular of the Medical 
Officer of Health: Local Government Board Remarks on the Clauses. 
Suggestions of the Society of Medical OfBcers of Health. Model Bye- 
Laws of the Local Government Board : As to Cleaning, &c. — As to Nuisances 
of Animals — As to Buildings. Metropolitan Asylums Board. Systems in 
Other Countries : Brussels : Waggon Sluices — Rules as to Meat. Paris. 
Germany. Berlin. Leipzig : The Suvern Mixture. Vienna. Complete 
Regulations in Denmark. Report of American Public Health Association. 
Quarantine: English System. Italy. 

An outline may be here given of the Sanitary Regulations that 
apply to our subject. 


Duties of a Medical OflBcer of Health (revised order of Local 
Government Board, 1891) — Rule 6. — On receiving information of the 
outbreak of any contagious, infectious, or epidemic disease of a dan- 
gerous character within the district, he shall visit without delay the 
spot where the outbreak occurred, and inquire into the causes and 
circumstances of such outbreak, and in case he is not satisfied that all 
due precautions are being taken, he shall advise the persons competent 
to act as to the measures which may appear to him to be required to 
prevent the extension of the disease, and take such measure for the 
prevention of disease as he is legally authorised to take under any 
statute in force in the district, or by any resolution of the sanitary 

7. Subject to the instructions of the sanitary authority, he shall 
direct or superintend the work of the inspector of nuisances, in the 
way, and to the extent, that the sanitary authorities shall approve. 

15. He shall give immediate information to us of any outbreak of 
dangerous epidemic disease within the district, and shall transmit to 
us a copy of each annual report and of any special report. 

Sanitary Inspectors — Rule 9. — He shall give immediate notice to 
the Medical Ofiicer of Health of the occurrence within the district of 
any contagious, infectious, or epidemic disease. 

10. He shall, subject to the directions of the sanitary authority, 
attend to the instructions of the Medical Officer of Health with respect 
to any measure which can be lawfully taken by an Inspector of 
Nuisances under the Public Health Act, 1875, or under any statute 
or statutes for preventing the spread of any contagious, infectious, or 
epidemic disease of a dangerous character. 

Public Health Act, 1875. — Earth-closets may be substituted for 
water-closets if the local authority approves, and the local authority 
may themselves undertake or contract with any person to supply dry 
earth or other deodorising substance to houses within their district 
for use in earth-closets (section 37). 

The keeper of a common lodging-house, in the first week of the 
months of April and October in each year, is required to limewash its 
walls and ceilings (section 82), and to give immediate notice to the 
Medical Officer of Health of any case of fever or infectious disease 
occurring in the house (section 84), and to give any officer of the 
local authority free access to every part of the house at all times 
when required (section 85). 

Similar regulations may be applied to houses let in lodgings. 

The following are the provisions against infection : — 

Where the Medical Officer of Health or any other legally qualified 
medical practitioner certifies that the cleansing and disinfection of any 


house or part thereof, or of any articles therein, would tend to prevent 
or check infectious disease, it is the duty of the local authority to 
give notice to the owner or occupier of the house in question requiring 
him to do the necessary work within a specified time. The person on 
whom the notice is served is liable on default to a penalty of Is. to 
10s. for every day during which he continues to make default, and 
the Local Authority is required to execute the necessary work, and 
recover the expenses incurred from the responsible party. 

If from poverty or other reason the person responsible is unable to 
carry out the requirements of the local authority, the latter may, 
with his consent, carry out the necessary work at their own expense 
(section 120). 

Any local authority may direct the destruction of any bedding, 
clothing, &c., which have been exposed to infection from any danger- 
ous infectious disease, and may give compensation for the same 
(section 121). 

The local authority may provide a proper place with all necessary 
apparatus and attendance for the disinfection of bedding, &,c., and 
may there disinfect any articles free of charge (section 122). 

They may also provide and maintain a carriage suitable for the 
conveyance of infectious patients, and pay the cost of conveyance of 
such patients to a hospital or elsewhere (section 123). 

Any person suffering from a dangerous infectious disorder who is 
without proper lodging or accommodation, or lodged in a room 
occupied by more than one family, or is on board any ship or vessel, 
or who is lodged in any common lodging-house, may, on the certificate 
of a legally qualified medical practitioner, be removed by order of any 
justice to any suitable hospital or place provided within a certain 
convenient distance. Any person wilfully disobeying or obstructing 
the execution of this order is liable to a penalty not exceeding £10 
(section 124). 

Regulations may also be made by any local authority for removing 
to a hospital persons brought within their district by any ship or 
boat, who are infected by a dangerous infectious disorder (section 125). 
Any person who — 

1. While sufiering from any dangerous infectious disorder, wilfully 
exposes himself without proper precautions in any street, public place, 
shop, inn, or public conveyance, or enters any public conveyance 
without previously notifying it to the owner, conductor, or driver, 
that he is so sufiering ; or, 

2. Being in charge of any person so sufiering, so exposes such 
sufierer ; or, 

3. Gives, lends, sells, transmits, or exposes, without previous dis- 


infection, any bedding, clothing, rags, or other thiiigs which have 
been exposed to infection — 

Is liable to a penalty not exceeding £5, and must also pay the 
amount of any loss or expense incurred in disinfecting the public con- 
veyance which lias been entered. 

Every owner or driver of a public conveyance must immediately 
provide for its disinfection after it has been used, to his knowledge, 
by an infectious person, or is liable to a penalty not exceeding £o 
(section 127). 

Any person knowingly letting for hire any house or part thereof, 
in which has been any person suffering from infectious disease, without 
proper disinfection to the satisfaction of a qualified medical practi- 
tioner, is liable to a penalty not exceeding £20 (section 128). 

Any person who, when letting a house or part thereof for hire, 
knowingly makes a false answer as to the occurrence of a case of 
infectious disease within six weeks previously, is liable to a jienalty 
not exceeding £20, or to imprisonment not exceeding one month 
(section 129). 

The Local Government Board may make or modify regulations for 
the treatment of persons affected with cholera or any other epidemic 
disease, and for the prevention of their spread, whether on water or 
land, and may prescribe by what authorities it may be enforced. 
Publication of such regulations in the London Gazette shall be regarded 
as conclusive evidence of such regulations (section 130). 

Hospitals for Infectious Diseases. — Any local authority may build 
hospitals or temporary places for the reception of the sick belonging 
to their district, or may contract with any person for the reception of 
the sick. Two or more authorities may combine in providing a 
common hospital (section 131). 

The expenses incurred in maintaining a patient, who is not a 
pauper, in such a hospital, may be recovered from the patient at any 
time within six months of his discharge (section 132). 

Any local authority may, with the sanction of the Local Govern- 
ment Board, provide, or contract with any person to provide a 
temporary supply of medicine, of course including disinfectants or 
antiseptics, and medical assistance for the poorer inhabitants of their 
district (section 133). 

Prevention of Epidemic Diseases. — Whenever any part of England 
appears to be threatened, or is affected by any formidable infectious 
disease, the Local Government Board may make and modify regula- 
tions for — 

1. The speedy interment of the dead. 

2. House-to-house visitation. 


3. The provision of medical aid and accommodation, the promotion 
of cleansing, ventilating, and disinfection, and guarding against the 
spread of disease — 

And may declare these regulations to be in force in any district, 
and to apply to any waters within English jurisdictions (section 134). 

The local authority within whose district the above regulations are 
in force shall see to their execution, and appoint the necessary officers 
for this purpose (section 136). 

The local authority and their officers shall have power of entry on 
all premises or vessels for the purpose of executing such regulations 
(section 137). 

The Local Government Board may, if they think fit, require two or 
more local authorities, to act together for the purposes of these provi- 
sions relating to the prevention of epidemic diseases (section 139). 

A penalty not exceeding £5 is incurred by any person who wilfully 
violates any of the regulations issued by the Local Government 
Board, or wilfully obstructs the carrying out of these regulations 
(section 140). 

Mortuaries. — Where the body of any one who has died of any 
infectious disease is retained in a room in which persons live or sleep, 
or where any dead body is in such a state as to endanger the inmates 
of the house or room in which it is retained, any justice may, on the 
strength of a certificate signed by a legally qualified medical practi- 
tioner, order the body to be removed, at the cost of the local authority, 
to any mortuary provided by them, and order its burial within a 
specified time. If the friends or relations of the deceased do not 
undertake the burial of the body within the time specified, it is the 
duty of the relieving officer to bury the body, but the expense may be 
recovered from the person legally liable to pay the expense of the 
burial (section 142). 

Port Sanitary Autlwrities. — The Local Government Board appoints 
the Sanitary Authorities of Ports from the neighbouring local 
authorities (section 287). The port sanitary authority may delegate 
its powers to any riparian authority within or bordering on their 
district. The Lord Mayor and Common Council of the City of London 
form the port sanitary authority of the Port of London (section 291). 

The General Order of Local Govemment Board for Preventing the 
Spread of Cholera, July 12, 1883, contains the following regulations : — 

1. Every ship is deemed infected with cholera in which there is, or 
has been during the voyage, or during the stay of the ship in a port 
in the course of the voyage, any case of cholera. 

Regulations as to Detention. — 2. If any officer of customs, on the 
arrival of a ship, ascertain, or has reason to suspect, that the ship is 


infected with cholera, he shall detain the ship and order it to be 
moored or anchored in such a position as he may direct. 

3, No person must leave the ship while thus detained. 

4, The oflBcer thus detaining any ship must give immediate notice to 
the sanitary officer of the place where the ship is detained. 

5, Such detention shall cease as soon as the ship has been duly 
visited and examined by the Medical Officer of Health, or if the ship 
is found to be infected with cholera, as soon as it has been moored and 
anchored in pursuance of Article 10 of this order. The examination 
must be commenced within twelve hours of the giving of the notice as 
aforesaid, otherwise the ship shall be released from detention. 

10. The master of any ship so certified to be infected with cholera, 
shall moor his vessel at the place fixed for that purpose under Article 6, 
and she shall remain there until the requirements of this order have 
been duly fulfilled. 

17. All articles soiled with cholera discharges must be destroyed, 
and all clothing and bedding shall be destroyed or disinfected. 

18. The ship must be disinfected and every article therein, according 
to the directions of the Medical Officer of Health. 

Dairies, Cowsheds, and Milk Shops Order of 1885. — All dairies and 
cowsheds, whether new or not, can only be occupied as long as the 
lighting, ventilation, including air space, and the cleansing, drainage, 
and water supply are such as are necessary or proper — 

(a) For the health and good condition of the cattle therein ; and 

(b) For the cleanliness of all milk vessels used therein ; and 

(c) For the protection of the milk against infection or contamination. 
It is unlawful for any person following the trade of a cowkeeper or 

dairyman, or purveyor of milk, or being the occupier of a milk store 
or milk shop — 

(a) To allow any person suffering from a dangerous or infectious 
disorder, or having recently been in contact with such a person, to 
milk cows or handle milk vessels, or in any other way to help in con- 
nection with the preparation or sale of milk ; or (6) still less himself to 
offend in a similar way. 

No water-closet, privy, urinal, &c., is allowed to communicate with 
any dairy or milk store, and the milk store must not be used as a 
sleeping apartment, nor for any other purpose incompatible with the 
cleanliness of the milk. Pigs are not allowed to be kept in a cowshed. 
Local authorities may make regulations for prescribing precautions to 
be taken against infection or contamination. The milk of a diseased 
cow shall (a) not be mixed with other milk, nor (b) sold or used for 
human food, and shall not (c) be used for the food of swine or other 
animals until it has been boiled. 


Regulation of Bakehouses (Factory and Workshops Acts of 1878 
and 1883). — Where a bakehouse is situated in a town containing over 
5,000 persons at the last census, all the inside walls and ceilings of its 
rooms, and all the passages and staircases shall be painted with oil and 
varnished with three coats, to be renewed once at least in every seven 
years, and washed with hot water and soap once at least in every six 
months (section 38, Act of 1878). 

1. No water-closet, privy, or ashpit shall communicate directly with 
the bakehouse. 

2. Any cistern for supplying water to the bakehouse shall be sepa- 
rate and distinct from the cistern supplying water to the water-closet. 

3. No drain or pipe for carrying off sewage matter shall have an 
opening within the bakehouse (section 15, Act of 1883). 

The occupier of any bakehouse whatever is liable to a penalty if the 
inspector of a local authority satisfies the court of summary jurisdiction 
that the bakehouse is, on sanitary grounds, unfit for a bakehouse 
(section 16, Act of 1883). 

The medical officer of health, for the purposes of these sections, 
has all the powers of an inspector under the Factory and Workshop 
Act, 1878. 

The Housing of the Working Classes Act, 1890, contains a number 
of regulations as to unhealthy areas. The medical officer of health is 
required, on complaint from ratepayers, to report on the condition of 
any area complained of as being unhealthy (section 5). Part II. relates 
to closing orders, demolition, re-housing, and re-building. 

Public Health (Water) Act, 1878.— It is the duty of every rural 
sanitaiy authority, from time to time, to ascertain the condition of the 
water supply within their district, and to take all the necessary steps 
for this purpose (section 7). 

The Vaccination Acts, 1867, 1871, 1874, prescribe measures to be 
taken for the vaccination or re-vaccination of unprotected persons. 

Burial Regulations. — Burials within any place of worship built since 
1848 are not allowed. No new burial ground can be opened within 
a,ny city or town, and burials within any existing one may be prohibited 
by order of the Queen in Council. 

Merchant Shipping Acts, 1854 to 1876; Passengers Act, 1855. — 
These contain orders as to the disposition of berths and air space 
allowed per person carried. 

The ventilation must be sufficient, no nuisances allowed, the drinking 
water of good quality and sufficient in amount. On long voyages each 
person must drink a daily allowance of lime juice, against scurvy. 
Every passenger vessel on a voyage of eighty days for a sailing vessel, 
or forty-five days for a steamer, when the number of passengers exceeds 


fifty, or of one day when the passengers exceed three hundred, must 
carry a medical man. In the absence of a doctor, instructions are 
given for the captain's guidance in cases of sickness. Captains are 
required to destroy the clothing and bedding of cholera patients before 
the ship enters an English port. Every passenger vessel must have at 
least two properly arranged water-closets, and sufficient space allotted 
for a hospital. 

Canal Boats Acts, 1877 and 1884. — Rules as to air space, cleanliness, 
and infectious diseases. 

The Infectious Diseases (Notification) Act, 1889. — Both the house- 
holder and the medical practitioner are responsible for the notification 
of each case of infectious disease to the medical officer of health for the 
district. This applies to any building, ship, boat (English or foreign), 
any tent, van, shed, or similar structure, whether belonging to Her 
Majesty or not. Penalty, forty shillings. The infectious diseases 
specified are : — Smallpox, cholera, diphtheria, membranous croup, 
erysipelas, scarlatina, scarlet fever, typhus, typhoid, enteric, relapsing, 
continued, or puerperal fever, and also any infectious disease to which 
the Act has been applied by the local authority. 

The Infectious Diseases (Prevention) Act, 1890. — Increased control 
over milk supply is given in section 4, which enacts that if the medical 
officer of health is in possession of evidence that any person in the 
district is sufiering from infectious disease attributable to milk supplied 
to a dairy within or without the district, or that the consumption of 
milk from such dairy is likely to cause infectious disease to any person 
residing in the district, such officer shall, after receiving the authority 
of a Justice for this purpose, have power to inspect the dairy in question, 
and, if accompanied by a veterinary surgeon, to inspect the animals in 
it. If on such inspection the medical officer of health is of opinion 
that infectious disease is caused from consumption of the milk supplied 
therefrom, he shall report thereon to the local authority, who shall 
give notice to the dairyman to appear before them, and to show cause 
why an order should not be made requiring him to discontinue supply- 
ing the milk. If in the opinion of the local authority he fails to show 
such cause, the order may be made, and shall hold good until they are 
satisfied that the cause of infection has been removed. 

Sees. 5 and 6 give increased powers of disinfection to the officers 
of the local authority. It is generally admitted that domestic disin- 
fection is of a most unsatisfactory character ; by section 6, power is 
given to remove bedding, &c., for the purpose of disinfection by the 
local authority at the cost of the latter. 

It is forbidden to retain the body of any person who has died of an 
infectious disease elsewhere than in a public mortuary, or in a room 


not used as a dwelling place, sleeping-place, or work-room, longer than 
forty-eight hours (sec. 8). 

By order of a Justice of the Peace, any person suffering from 
infectious disease, and then in a hospital for infectious disease, may, 
although unwilling, be detained there until free from infection, if it 
can be shown that he is without proper means of isolation and lodging 
elsewhere (sec. 12). 

The throwing of infectious rubbish into ashpits, &c., is forbidden 
(sec. 13). 

The local authority is required to provide free temporary shelter 
with the necessary attendance to the members of any family who have 
been compelled to leave their houses to enable them to be disinfected 
by the local authority (sec. 15). 

The bodies of persons dying of infectious diseases in . hospitals are 
only allowed to be removed for the purpose of being forthwith buried 
(sec. 9). 

The Public Health Amendment Act, 1890, does not apply to the 
metropolis. It forbids the discharge of injurious matter into the 
sewers (sec. 16), gives power to regulate public conveniences, and 
those in lodging houses, factories, or workshops. Rooms over privies, 
middens, or ashpits, are not allowed to be used as dwelling or sleeping 
rooms (sec. 24). It is not lawful to erect a new building on any 
ground filled up with offensive matter, unless the latter is removed by 
excavation, or has become innocuous. 

Urban authorities may make bye-laws for prescribing the times for 
removal through the streets of offensive or noxious matters, and for 
providing that the vessels or carts be properly constructed and covered 
(sec. 26). The section of the Public Health Act relating to un- 
sound meat is made to apply to articles which have been already 
sold (sec. 528). 

The Public Health (London) Act, 1891, consolidates and amends all 
previous sanitary enactments. Section 15 says — Any person damaging 
or destroying any drain, water-closet, or Avater-supply apparatus, is 
liable to a fine of £5 (sec. 15). 

It is compulsory on the sanitary authorities and County Council to 
make bye-laws for the cleansing of streets and prevention of nuisances 
from rubbish, offal, &c., and as to paving of open spaces about houses ; 
and on the County Council to make bye-laws for the removal of filth, 
&c., in properly covered vessels, and as to the filling up of cess- 
pools, &c. 

The petty sessional court may prohibit the using of any place for 
the keeping of any animal, if it is proved to the satisfaction of the 
court that the place is unfit for this purpose (sec. 18). (This 


section applies to fowl-houses, pigeon-houses, rabbit-hutches, <kc., and 
the keeping of cats and dogs.) 

By section 22 the removal of house refuse and street refuse is placed 
under the same category as offensive trades under private control, and 
the sanitary authority are liable to be proceeded against for any in- 
fringement of the bye-laws made by the County Council in this behalf. 
The regulation of dairies and cowsheds is placed under the control of 
the County Council (sees. 23 to 28). It is made the duty of the 
sanitary authority not only to keep the streets swept and cleaned, but 
also to secure the regular periodic removal of house refuse. If after 
forty-eight hours written notice, when the house refuse has not been 
removed from any premises at the proper period, the sanitary authority 
fail without reasonable cause to comply with this notice, they are liable 
to a fine not exceeding £20 (sees. 29, 30). 

Sec. 48 constitutes a dwelling-house without a proper supply of 
water unfit for habitation; and by section 49 makes any Water 
Company liable to a fine of .£10 if within twenty-four hours after 
cutting off the water supply to any house for non-payment of water- 
rates they do not give notice to the sanitary authority. Every sanitary 
authority is required to make bye-laws for the cleansing of receptacles 
for storage of water for drinking or domestic purposes. 

Sees. 55 to 57, on the notification of infectious diseases, make it 
compulsory on Medical Officers of Health to send a copy of the 
certificate to any school attended by any child who is an inmate of 
the infected house. 

Sees. 58 to 81 make compulsory the provision of disinfecting apparatus 
and carriages for carrying infected materials, free of charge, by the 
Sanitary Authority. 

Every Sanitary Authority is required to provide and fit up a public 
mortuary (sec. 88). 

Memorandum on Hospital Accommodation— Local Government Board. 
— When two contagious diseases break out at the same time, they 
should each be separately isolated. In towns, and for several villages 
of smaller size, there should be provided at least two special wards 
with four beds in each, in order that the sick may be isolated from 
the commencement. Proposed plans and ■ sections accompany the 

In rural districts without a hospital, a trustworthy married couple 
without children may be charged with the isolation and care of cases 
of infectious disease. In the event of a more serious epidemic several 
lodgings may be hired, or the sick may be isolated in temporarily 
erected tents or barracks. Fever hospitals in urban districts ought to 
have one bed for every 1,000 inhabitants. In a manufacturing town 


with a very dense population, the proportion oxight to be even greater. 
Permanent fever hospitals are built on the system of separate pavilions. 
Illustrations and details are given in the Memorandum, which cites 
as examples St. Thomas's Hospital, the Herbert Hospital, and the 
Royal Infirmary at Edinburgh. The laundries and mortuaries should 
be in separate buildings. 

In wards for infectious diseases there should be openings for 
admission of fresh air between each bed, a little above the floor, so 
that pure air bathes the patient's bed. They should be furnished 
with a grooved fastening, so that the admission of air can be gradu- 
ated. The openings for the extraction of foul air should be near 
the ceiling, and as remote as possible from those admitting fresh air. 
They should, unless entering into the chimney breast, be cai'ried 
vertically to the roof, and be pi-ovided with an aspirating cowl. 
2,500 cubic feet of fresh air should be supplied for each patient per 
hour. The openings should be easily cleansed and freed from dust, 
and protected by an outside grating. Every hospital should possess 
a disinfecting apparatus. 

Memorandum on Ambulances.— In the construction, special regard 
should be had to the fact that after each \ise, it has to be cleaned and 
disinfected to the satisfaction of a Medical Officer. 

Bules for Hospitals for Infectious Diseases (Local Government 
Board). — Among these are : — 

(3) No person is admitted without the permission of the Medical 

(4) No patient is permitted to leave until discharged by him. 

(5) The patient's clothes must be disinfected before being given up 
to him at his discharge. 

(6) Officers and servants are not allowed to leave without authority 
of the Medical Officer, and they must first change their clothes. 

Circular of the Medical Officer (Local Government Board). — After 
insisting on the proper ordering of houses, drains, &c., the circular 
contains : — 

"Sec. 4. In the removal of filth during epidemic disease, it is 
commonly necessary to employ chemical agents for reducing and 
removing the ofience or harm which may be involved in the disturb- 
ance of the filth. In the removal of privy contents these agents are 
more particularly wanted if the disease be cholera or enteric fever. 
The chemical agent should be used liberally over all exposed surfaces 
from which filth has been removed. Unpaved earth close to dwellings, 
if it be sodden with slops or filth, ought to be treated in the same 

" Sec. 5. Sources of water supply should be well examined. Water 


from sources which can in any way be tainted by animal or vegetable 
refuse, especially those in which there may be any leakage or filtration 
from sewers, drains, cesspools, or foul ditches, ought no longer to be 
drunk, above all where the disease is cholera, diarrhoea, or enteric 
fever. If unfortunately such is the only water to be got for the time, 
it must be boiled, and then not drunk later than twenty-four hours after 
boiling. Filtering of the ordinary kind cannot by itself be trusted to 
purify the water (see p. 15). It cannot be too distinctly understood 
that dangerous qualities of water are not obviated by the addition of 
wine or spirits." 

Sec. 6 (after remarks about dairies). ..." Even apart from 
any apprehension of milk being concerned in a particular outbreak of 
disease, it is desirable that English people should adopt the custom, 
which is always followed in some Continental countries, of boiling all 
milk at once upon its reception into a house." 

Sees. 7 and 8 deal with washing, lime-whiting, overcrowding, and 

Sec. 9 enjoins cleanliness, rapid removal or destruction of refuse,, 
and avoidance of delay in disinfecting. 

Sec. 10 gives directions as to discharges from the sick (see p. 233). 
" In enteric fever and cholera the evacuations should be looked upon 
as capable of communicating an infectious quantity to any night-soil 
with which they are mixed in privies, drains, or cesspools, and after 
such disinfection of them as is practicable they should be disposed of 
without delay and under the safest conditions the local circumstances 
permit." (It is quite impossible for this to be done by private effort ; 
the evacuations can only be securely sterilised by heat, and this would 
involve either a s'team apparatus or a dust-destructor. The local 
authorities must arrange to remove the evacuations daily in sealed 
iron receptacles, which must be heated for several hours in steam 
ovens, or steam passed through them, the gases being led into a fire 
and burnt. A small quantity, about 1 in 500, of phenol, or a cresol 
preparation (see p. 170) should be added ; it has been proved that dis- 
infectants, when hot, act with much more energy than when cold ; or 
mercuric chloride may be used. The residue is then safe.) 

"Sec. 17. Provision by the public authority for disinfection by 
heat of bulky articles, and of those which cannot without injury be 
exposed to chemical agencies, ought always to be in readiness." (Such 
provision could be associated with the arrangements for the sterilisation 
of excreta described above. Many of the existing apparatus are not 
large enough.) "Without such provision no complete disinfection can 
be eflfected. Partial and nominal disinfection, besides being wastefui, 
may be mischievous, as giving rise to false security." 


Sec. 18. This rule commends a system of domestic disinfection to 
sanitary authorities "who have already provided adequate public means 
for the disinfection and for the disposal of infected matters and things." 
Soiled linen is treated with mercuric chloride solution. 

"In places provided with proper systems of excrement disposal, 
excrements of cholera and enteric fever, after having been treated in 
detail with the same disinfecting solution (acidified mercuric chloride 
in ample quantity), may be safely put into the ordinary closet ; but 
special care as to the flushing of drains and sewers, and special frequency 
in the removal and exchange of excrement receptacles, must be insisted 
upon. Where the closet is one that communicates with the cesspool 
or privy pit, the best arrangement for the disposal of infected stools 
that under these improper local circumstances may be found practicable 
will have to be adopted." This rule ought to be reconsidered. Koch 
has proved that mercuric chloride may easily be insufficient even in 
larger amount than is here recommended (p. 137). The throwing of 
cholera excreta, even " disinfected " as here described, into closets, to 
pass thence into rivers and streams, might spread the disease through 
an entire neighbourhood. Nothing short of the sterilisation by heat, 
as detailed above, is at all certain. 

"A substance generally available in the removal of filth from privies 
and ashpits, and for application to foul earth and the like, is sulphate 
of iron (green copperas), either in a strong solution made by stirring 
crystals of the salt with five or ten times their bulk of hot water, or in 
the form of powder, to which form the crystals may easily be brought 
by desiccation. This agent should be used in quantity sufficient to 
destroy all odour, and in the removal of filth accumulations it should 
be well mixed with successive layers of the matter to be removed. 
The dry form of application is to be preferred where masses of wet or 
solid filth have to be dealt with." (But Dr. Thome himself says : " It 
cannot confidently be stated that either the iron salt or any available 
substance will effect a true disinfection of such masses of filth as are 
here in question. The removal of dangerous filth is here the object to 
be attained." It is strongly to be hoped that a protest will be made 
against the recommendation of a plan admittedly inefficient, since 
removal without exposure," and the subsequent action of heat, are the 
only courses eff'ectual. Even for temporary removal of stench, there 
are better remedies than sulphate of iron; for instance, a cresol powder, 
or liquids of the Sanitas type, or saprol, or other pyridine-containing 

"For the disinfection of the air of rooms . . . sulphurous acid 
, , . is ordered, and wall paper should be stripped." . . . 

Suggestions of the Society of Medical Officers of Health. — Most of 



these have been previously noticed. The following are the chief 
points : — 

" 1. Hang up a sheet outside the door of the sick room, and keep it 
wet with a quarter of a pint of carbolic acid, No. 4, or a pound of 
chloride of lime, with a gallon of water. The floor should be sprinkled 
. . . and the cloths hung up." 

" 2. Everything that passes from the sick person should be received 
into ^ pint of green copperas, 1 lb. to the gallon. A like quantity to 
be added before emptying." 

" 3. Every sink, closet, or privy should have a quantity of one of 
the above-named disinfectants poured into it daily, and the greatest 
care should be taken to prevent the contamination of well or drinking 
water by any discharges from the sick person." 

" 4. All cups, glasses, spoons, &c., used by the sick person should he 
first washed in the above-named solution of carbolic acid, and after- 
wards in hot water, before being used by any other person," (It 
would be better to insist that the utensils used by the sick person 
should not be used by any one else. At the end of the illness, 
they are better destroyed, but if they must be used, they should be 
boiled for an hour or two with water and washing soda, and then 
wiped dry. No carbolic acid is necessary.) 

" 5. All the bed and body linen . . . before being taken from 
the room, should be first put into a solution of carbolic acid . . ." 

6. Prescribes linen garments for nurses, and washing the hands 
with carbolic soap. 

7. Visitors should not be allowed, as their clothing is apt to carry 
away infection. 

" 8. The scales and dusty powder which peel from the skin in scarlet 
fever, and the crust in small-pox, being highly infectious, their escape 
may be prevented by smearing the body of the sick person all over 
every day with camphorated oil. This and the after use of warm 
baths and carbolic soap are most essential. The sick person must not 
be allowed to mix with the rest of the family until the peeling has 
entirely ceased and the skin is perfectly smooth ; clothes used during 
the time of illness, or in any way exposed to infection, must not be 
worn again until they have been properly disinfected " (p. 283). 

9. Directions for final disinfection of the room by burning sulphur, 
and bedding, &c., by heat. The amount prescribed is not sufficient 
(see p. 94). 

10. Children from an infected house not to attend school until 
they obtain a certificate from the medical attendant. 

11. In case of death the body should not be removed from the 
room except to a mortuary ; a pound or two of carbolic powder should 



be put into the coflBn, which should be fastened down and buried 
■without delay. (Cremation is here to be advocated). 

Model Bye-Laws of Local Goverament Board as to Cleansing, &c 

The following pertain to our subject (the wording is slightly con- 
densed) : — 

Sec. 1. The occupier of any premises abutting on a street shall clean 
the adjoining pavements at least once a day, except on Sundays. 

Sec. 2. He shall remove house refuse from his premises at least once 
a week. 

Sec. 3. He shall at least once in three months cleanse earth-closets 
provided with a fixed receptacle and supply dry earth ; 

Sec. 4. Those with a movable receptacle, at least once every week ; 

Sees. 5 and 6. Privies of either kind, at least once a week ; 

Sees. 7 and 8. Ashpits, whether mixed with faecal matter ornot; and 

Sec. 9. Cesspools. 

Model Bye-Laws as to Nuisances and Animals. — Sec. 3. Salt and 
snow must be effectually removed. 

Sec. 4. Ashes, &c., must not be deposited on paths or roads, must be 
swept up, and must be removed in a covered receptacle, instead of in 
open pails. 

Sec. 4a. Privies, cesspools, <tc., must be emptied within special 
hours (p. 240). 

Sees. 5 to 8. Ashes, &c., must be removed in covered carts, to 
special depdts, 100 yards distant from houses, every twenty-four hours. 

Sec. 9. When filth is deposited for agricultural purposes, the distance 
from the nearest inhabited premises must be at least 100 yards, and 
the filth must be forthwith ploughed in or covered with mould 
(ordinary earth does not sterilise it, see p. 238). 

Sec. 10. Pigs must not be kept, nor swine dung deposited, within 
100 yards of a house, nor so as to pollute a water supply. 

Sec. 11. Cattle and their dung must not endanger any water used 
for drinking, domestic, or dairy purposes. 

Sec. 1 2. Regulations as to manure from stables, &c. 

As to Buildings. — Sees. 55 to 59. Rooms and public buildings must 
have proper ventilation according to specified details. 

Sec. 60. Drains and water pipes must be disconnected from the 
sewer by ventilated traps. 

Sec. 62. Regulates the material, diameter, setting, jointing, and 
course of drain pipes ; and 

Sees. 63, 64, and 65. The traps, gratings and ventilating shafts 
which should be carried to the top of the house. 

Sec. 66. No inlets to drains are allowed within houses. The soil 
pipe must be at least 4 inches in diameter and be fixed outside the 


building and continued upwards without bends or angles to a height 
above the top windows. All waste and overflow pipes must be taken 
through an external wall of the house, and discharge in the open air. 

Sees. G8 and 69. Water-closets within houses shall have at least 
one of their sides to an outer wall, must be ventilated, have a special 
cistern and sufficient flush, must not have a "container," or "D-trap." 

Sees. 70, 71, and 72 relate to earth-closets. 

Sees. 73 to 79. Privies must be 6 feet from a house, 40 to 50 feet 
from any source of drinking water (not sufficient — Neicalwlme), easily 
accessible, ventilated, the floor non absorbent, raised above the ground 
level, and sloping towards the door (to prevent stagnant water). 
The receptacles must not be exposed to rainfall or drainage. 
• Sees. 80 to 85. Ashpits must be 6 feet from a house, 30 to 40 feet 
from any well, &c., roofed, cemented, and easily cleaned. 

Sees. 86 to 89. Cesspools must be 50 feet from a house, 60 to 
80 feet from any well, &c., easily emptied without passing through 
the house, properly cemented, unconnected with a sewer, covered, 
and adequately ventilated (cesspools should be forbidden where 
there are sewers). 

The model bye-laws as to lodging-houses resemble those of the 
Public Health Act, 1875, with many additions and improvements. 
Those as to slaughter-houses are in considerable detail. 

Metropolitan Asylum's Board. — The disinfection of ambulance car- 
riages and steamers is done by washing with carbolic acid. 

The hospital linen is soaked in carbolic solution, and then boiled 
and washed (it requires not less than 1 in 20 carbolic to disinfect 
linen ; the solutions usually employed are not as strong as this — e.g., 
the one recommended by the Society of Medical Officers of Health 
(p. 153) is only \ pint to a gallon, or 1 in 32. This means that 
carbolic disinfection as commonly carried out is imperfect. In the 
new hospitals clothing is disinfected by steam). 

Legislation as to Vagrants.— On July 19, 1894, a conference of 
Medical Officers of Health and others was held at the hall of the 
London County Council to consider whether means could be adopted 
to prevent the spread of infectious diseases by vagrants. The matter 
is still under discussion. 


In some respects the sanitary administration of Brussels is superior 
to ours, and compulsory notification has been enforced since 1824. 

Slaughtering is only allowed in the town abattoirs. The meat is 
inspected and stamped, and the name and address of the owner, and 
destination of the meat, are recorded, with the date and hour; this 


arrangement has secured almost perfect protection against diseased 
meat, and also that it should be fresh. Even " offal " must be dressed 
at the abattoir and stamped. During transport the stamp and certifi- 
cate must be shown when demanded. The control of other foods is 
also much more satisfactory than ours. 

The Waggon Sluices used to clean deposits from the sewers travel 
along rails throughout their length. The deposits being continually 
removed, cannot decompose and produce foetid gases, and the air of the 
sewer is comparatively pure. 

The corpses of persons having died of an infectious disease are 
wrapped in linen clothes soaked in carbolic acid. The body is then at 
once conveyed to the observation chamber of the mortuary outside the 
town, and is interred as soon as certain signs of death have appeared. 
Special clothes are worn by the undertaker's men, and these are re- 
turned after use to the station for steam disinfection. 

Germany has necessarily instituted compulsory inspection of pork 
(see p. 271), and authorised inspectors are appointed for this purpose. 
If infested with trichinosis, the fat only can be used, after being 
cooked for three hours ; the rest of the meat is buried. Tuberculosis 
is also keenly looked after. 

The rules as to corpses and burials are very explicit (see p. 280). 
Corpses must not be exposed in the churches. Midwives are forbidden 
to wash or lay out corpses. 

In Berlin only water-closets and movable tubs are allowed. Steam 
disinfection is carried out at the Reichemberger Strasse station. 
Mercuric chloride is not used as in Paris, but the walls of rooms are 
rubbed with bread and then washed with 2| to 5 per cent, carbolic 
acid. Various chemical methods of disinfection of excreta are used in 
Leipzig. "The Suvern Mixture" is made by soaking 42*5 grammes of 
quicklime with 102 of water, and adding thereto 8*5 kilos, of coal-tar 
and 8 '5 of magnesium chloride in an equal quantity of water; it is 
diluted with water when used. Half a kilo, is used for each person 
per day. It is mixed with the excreta when removed ; the mixture 
then flows into settling reservoirs, the liquids run off into the sewers, 
and the solid deposit is cleared out about once a year. Palmberg 
states that both the solid and liquid matters are rendered inoffensive. 
The theory is that the carbonic acid developed by the fermentation of 
the organic matters combines with the lime to cause a deposit of car- 
bonate of lime which encrusts or petrifies the microbes ; the spores as 
they develop are destroyed in the same way. The ammonia generated 
by putrefaction is fixed by the magnesium chloride, the sulphuretted 
hydrogen by the lime. " The deposit consists of carbonate of lime 
mixed with organic matters ; it is greyish in colour, inodorous, and 


aseptic."* It is useless for manure. The process of Friedrich and 
Glass is also much used. The composition of the disinfecting powder 
is not given. 

In Vienna, 5 per cent, carbolic acid (the least eflfective strength), 
sulphurous acid fumigation, and steam are the legal disinfectants. 

In Denmark very elaborate regulations are in force, and the follow- 
ing summary may therefore be useful as a model for further legislation 
in this country. The rules were proposed by the Royal Board of 
Health for disinfection, and were carried out in pursuance with the 
Act of April 20, 1888, on measures against the spread of infectious 
diseases, and are now established in Denmark in virtue of the authority 
vested in the Minister of Justice by the said Act. It rests with the 
Boards of Health to supervise the proper carrying out of public disin- 
fection ; the Boards must also see that the necessary staff and appli- 
ances are at hand, and that the former are properly instructed in their 
duties. It is the duty of the medical man sending in the requisition 
for disinfection to state what rooms or things are to be disinfected. 

Disinfectants. — (1) Boiling in water for at least twenty minutes. 

(2) Steam under or without pressure in "disinfecting ovens"; those most 
generally used are Reek's and Geneste & Herscher's (see pp. 45, 47). 

(3) Carbolic acid in 5 per cent, solution, " strong carbolic water," or in 
2 per cent, solution, "weak carbolic water," according to the purpose 
for which it is used. (4) Chloride of lime is used partly as a powder 
mixed with twice the quantity of clean dry sand, for covering excreta, 
dung-heaps, and such like ; partly in strong solution, viz., 4 parts to 
100 parts. To be thoroughly efficient, chloride of lime must meet the 
requirements of the Danish Pharmacopoeia, and contain 20 per cent, of 
available chlorine, and must be kept in the dark in corked glass recep- 
tacles, which is also the case with the solutions. The solutions are 
prepared best in the following manner : — The chloride of lime is made 
with a little (clean) water to a smooth paste, after which the rest of 
the water is gradually stirred in for thirty minutes. An insoluble 
residue will remain, which may be removed by filtration, but this is 
not necessary when the solution is only to be used for disinfecting the 
patients' excreta, «kc. The solutions are most efficient when freshly 
made. (5) Mercuric chloride (corrosive sublimate) in a solution of 
1 part to 1,000 parts of boiled water should, on account of its poisonous 
nature, be only used under the supervision of the sanitary authorities 
or of medical men ; on this account also no vessels should be used in 
the preparation of the solution from which either man or beast drink 
or eat, nor such in which drink or food is kept. Further, the solution 
of mercuric chloride must not be thrown away in places where such 

* Pcdmberg, p. 409. 


may give rise to poisoning ; should the solution be used in the disin- 
fection of any utensil, it must, when the disinfection is finished, be 
carefully removed from the object disinfected by repeated rinsing or 
washing with clean water that has been boiled. A solution of soda 
should be employed for the same purpose in rooms which have been 
disinfected with mercuric chloride (see below). As mercuric chloride 
is decomposed by metals, metallic vessels must not be used in the 
preparation of the solution, neither must any articles made of metal 
be disinfected with this agent. 

To prevent mistakes the solution of mercuric chloride may l)e 
coloured with any dye which does not injure the objects to be disin- 
fected (especially woollens, or silks which easily take dyes), for instance 
the aniline dye, which is at present manufactured in Germany and 
known as Wasserblau, which can be obtained from C. A. Kahlbaum, 
Berlin. A little acetic acid is recommended to be added to preserve 
the colour. (6) Aeration may be employed to second any of the other, 
agents, or when it is impossible to disinfect in any other way, in which 
case it must be continued for three or four weeks. (7) All worthless 
articles (straw, hay, or seaweed mattress stuffing, old clothes, cloths 
which have been used for wiping away infectious discharges, &c.) 
should be burnt as soon as possible, the necessary precautions being 
taken to prevent the spread of the disease. 

Special Rules for Disinfection.— 1. The o?isc/tar^es of patients (dejec- 
tions, vomited mattei", sputa, urine) must be immediately mixed with 
the strong solution of chloride of lime, or with strong carbolic water. 
It is advisable to pour a little of these disinfectants into the vessel 
before it receives the discharge. The total quantity of the agent 
employed must be at least equal to that of the discharge. The mix- 
ture should be immediately poured into a tight, well-covered vessel, 
specially used for that purpose, and placed in an isolated place; in 
this vessel the mixture is to remain until the disinfectant has acted — 
viz., one hour when a solution of chloride of lime is iised ; four hours 
when carbolic water is used. This vessel should be emptied daily, 
preferably into a pit, dug especially for that purpose ; if this is not 
possible, into a privy, the contents of the pit or privy to be imme- 
diately covered with a layer of the mixture of chloride of lime and 
sand, should circumstances necessitate the immediate emptying of the 
mixture into the pit or privy. 

It should be carefully stirred with a stick, and the stick left in it. 
If the mixture is emptied into a tub, this must be changed daily. 

2. Privies. — Excreta contained in privy pits or tubs should be 
covered with a thick layer of a mixture of 1 part of chloride of lime and 
2 parts of sand. Privy tubs should be frequently emptied, and after- 


•wards disinfected with a 4 per cent, solution of chloride of lime and 
6 per cent, carbolic water ; the seat and floor of the privy should be 
washed with one of these disinfectants at least twice daily. The pan 
and pipe in water-closets, as also urinals, should be cleansed at least 
twice daily with one of these disinfectants. 

3. Clothing. — Dirty clothes, bed-clothes, pocket handkerchiefs, 
towels, cloths, and such like, should not be shaken or brushed pre- 
vious to disinfecting. In Denmark the rules in force are as follows : — 

Everything which can be washed without injury should immediately 
be put into boiling water for thirty minutes, or into 2 per cent, 
carbolic water, or the solution of mercuric chloride, for at least four 
hours ; after being wrung out, the articles should be placed in a vessel 
full of water, in which they remain until they can be washed. If the 
articles cannot be placed in the above-mentioned disinfectants in the 
sick room itself, they must only be taken from it wrapped up in a 
sheet or sack saturated with 2 per cent, carbolic water. Clothes 
should not be sent to the wash from infected places, unless they have 
been subjected to the treatment above mentioned, and should not be 
washed until they have been boiled for thirty minutes in soap and 
water. Hay and straw mattresses should be opened after being 
moistened in such a way that their opening causes no dust ; the hay 
or straw should be removed or burnt, the covers treated in the manner 
above mentioned. Persons employed in washing the articles above 
mentioned should, on the completion of their work, disinfect them- 
selves according to the rules given below for the persons engaged in 
disinfection. Everything which cannot stand boiling water or wash- 
ing should be taken in the manner above described to the disinfecting 
oven, to be disinfected with steam. If this is impossible, the articles 
should be brushed with a brush dipped in strong carbolic water; after 
which they should be aired for three or four weeks in a dry place pro- 
tected from rain — places where there is a draught being preferred. 
Spots of blood or matter must be removed by soaking in a cold disin- 
fecting fluid, previous to disinfection, either with boiling water or 
steam. Leather, morocco, or indiarubber articles (boots and shoes, 
boxes, bags, <fec.), which would be injured by steam, should be carefully 
washed over several times with 5 per cent, carbolic water. 

4. Upholstered furniture, carpets, curtains, and such like, when 
circumstances permit, should be disinfected with steam ; they should 
not be beaten or brushed previous to disinfection, and should be taken 
to the place for disinfection wrapped in sheets or sacks saturated with 
2 per cent, carbolic water. When it is not possible to employ steam, 
the articles must be brushed with a brush dipped in 5 per cent, 
carbolic water (if they can stand it), after which they should be aired 


for three or four weeks in a dry place, protected from rain; a 
draughty place being preferred.^ Polished or carved furniture, pic- 
tures, and articles which cannot stand strong carbolic water, should 
be wiped with soft cloths dipped in 2 per cent, weak carbolic water 
and wrung out; they should then be immediately dried with a clean, 
dry cloth. Any parts of the above-mentioned articles which are not 
polished or stained, should be washed twice with 5 per cent, carbolic 
water ; they must be first washed with hot soap and water, should 
they be very dirty. The cloths washed in the cleaning should be 
washed or burnt immediately. All articles which can be placed in a 
fluid without injury, should be boiled or put into a strong or weak 
carbolic water for four hours, according to their nature. Articles of 
no value should be burnt. 

5. Rooms, Carriages, &c. — The sweeping or dusting of such is not 
permissible. Whitewashed or oil-painted walls, floors, ceilings, 
windows, doors, wainscotting, and other woodwork, should be dis- 
infected with 5 per cent, carbolic water or solution of mercuric 
chloride; the latter only under supervision (see above). "With 
these disinfectants the surfaces should be wiped with cloths or, 
(when they can stand it) should be scrubbed with a scrubbing brush, 
or sprinkled by means of a syringe or spray apparatus constructed 
for that purpose. Plaster walls may also be disinfected by giving 
them a coating of a mixture of 1 part chloride of lime and 2 parts 
water. Such surfaces as cannot stand washing or scrubbing, for 
instance wall papers, covers, or fixed cushions, should be sprinkled 
with the disinfectant fluids above mentioned (which do not injure 
many wall papers) or carefully rubbed with pieces of soft bread, 
the crumbs being swept up and burnt. Surfaces disinfected with 
the solution of mercuric chloride should be washed over or sprinkled 
with a solution of soda (1 part to 100 boiled water), at least thirty 
minutes after disinfection. Care should be taken that all parts of 
the surfaces to be disinfected are thoroughly exposed to the dis- 
infectants, and that these latter penetrate into all cracks and holes, 
which, if necessary, should be scraped free from all dirt and dust, 
this being wiped away with cloths dipped in a disinfectant fluid, 
the cloths to be afterwards burnt. Special care should be taken 
in cleansing such parts of the floors or walls as have been soiled 
by the patient's discharges ; wall paper thus soiled, after having 
been moistened with one of the above-mentioned solutions should 
be taken off or burnt. Disinfection being completed, the room, 
carriage, &c., should be left for twelve hours ; after which time the 
surfaces disinfected should be thoroughly washed with warm water 
and soap. Finally, they should be exposed to a thorough draught. 


if possible for at least a week. In ships, special care should be taken 
as to the disinfection of the bilge. Ships in harbour are disinfected 
according to special rules, under the supervision of the authorities 
in question. In ships at sea, the bilge water should be pumped 
out, and the bilge thereafter rinsed out with salt water at least 

6. Persons] who have been in contact with patients suffering with 
infectious diseases, should first wash their hands, arms, and face in 
weak carbolic water or a weak solution of chloride of lime, then in 
warm soap and water. Their clothes and hair should be brushed with 
brushes dipped in weak carbolic water. Persons devoting themselves 
to the nursing of patients, or constantly staying in the sick room, 
should, when their task is completed, thoroughly disinfect themselves 
before visiting healthy persons or dwellings. This disinfection should 
consist of thorough washing of the whole body, and brushing of the 
hair with weak carbolic water, or weak solution of chloride of lime ; 
after which a warm bath should be taken, if possible ; finally, clothes 
free from infection should be put on. Clothes worn while nursing 
should be left in the infected place. Nurses should carefully wash 
their hands, first with carbolic water, or the weak solution of chloride 
of lime, and afterwards in warm soap and water, every time they 
have reason to believe that infectious germs have stuck to them. 
Nail brushes should be used for brushing the nails. Convalescents 
should be washed all over the body (hair included) with weak 
carbolic water, or the weak solution of chloride of lime, after which 
they should take a warm bath, and put on a suit of clothes free from 
infection, before they mix with healthy persons. The clothes worn 
during illness should be disinfected according to the regulations laid 
down above. Persons employed in disinfecting rooms, furniture, &c., 
should wear a linen suit consisting of a blouse, trousers, and cap with 
a brim in front and behind, which suit should be disinfected after 
having been used. The persons who have been engaged in disinfect- 
ing should cleanse their hands, arms, and faces as above prescribed. 

7. Drinking water, milk, beer, provisions, &c., which have been 
exposed to infection, should be rendered harmless in the most eflfective 
manner possible. In no case should they be consumed unless they 
have been thoroughly boiled a short time before. Any scraps left 
should be boiled before being eaten. 

The Report of tlie Committee on Disinfection of the American Public 
Health Association, Baltimore, 1885, recommends : — 

For spore-bearing bacteria {e.g., anthrax) — 

1. Combustion wherever possible. 2. Steam under pressure at 
110° C. for ten minutes (not long enough). 3. Boiling for an hour. 


4. Chloride of lime, 4 per cent, solution (almost inert unless acidified, 
see p. G4). 5. Mercuric chloride-, 1 in 500. 

For non-spore-bearing bacteria {e.g., cholera) — 

1. 'Five. 2. Boiling half an hour. 3. Dry heat at 110° for two 
hours. 4. Chloride of lime, 1 to 4 per cent. 5. Soda chlorinata (p. G3), 
5 to 20 per cent, (also almost inert unless an acid is added). 6. Mer- 
curic chloride, 1 in 1,000 to 1 in 4,000. 7. Phenol, 2 to 5 per cent. 
8. Sulphur dioxide for twelve hours, until there is 4 per cent, in the 
air, preferably moist (see p. 92). 9. Cupric sulphate, 2 to 5 per cent. 
10. Zinc chloride, 4 to 10 per cent. 

Quarantine. — The arguments for and against quarantine, as compared 
with our system of port sanitary inspection, cannot be discussed at 
length here. Quarantine has been described as an elaborate system of 
leakiness, and our English method seems to be as effective, without its 
hardships. In a commercial country, rigid quarantine regulations 
would be fatal to all interchange of commodities, whilst, if partial 
measures are adopted, there is danger to be feared from laxity on the 
part of the local authorities, who may rely on these partial measures 
ii% being complete. With infectious diseases like cholera, in which the 
period of incubation is about fifteen days, it is possible for a person to 
arrive in this country from the Continent and pass the port inspection 
before any symptoms of the disease are manifest. It is therefore im- 
portant that the local authorities throughout the country should have 
adequate provision for dealing with such sporadic cases, and medical 
officers of health receive special instructions from the Local Government 
Board when there is any likelihood of such cases reaching this country. 

In August, 1894, special regulations of this character were issued, 
and diarrhoea was scheduled as an infectious disease which might be 
reportable to the local sanitary authority. Special beds at such times 
are arranged for by the Metropolitan Asylums Board and other author- 
ities, and instant removal of suspected cases to the various hospitals is 

At the international conference held in Paris in 1894, the following 
precautions were agreed upon : — The convention regulates the pilgrim 
ships from India and Oceania, and the sanitary and police rules under 
which they shall be ; it provides for the watching and care of pilgrims 
in the Bed Sea, and for the protection and sanitary rules of the places 
of traffic in the Persian Gulf. The carrying out of the regulations are 
to be entrusted to a commission, sitting in Constantinople, to which 
very great powers are committed. The internal sanitation of Mecca 
itself is left for the present to the management of the Sultan, to whom 
strong representations have been made.* 

♦ Brit. Med. Joum., April 28, 1894. 


Prof. De Chaumont, of Netley Hospital, held that quarantine regu- 
lations were absolutely useless, interrupted business, and delayed 
travellers, without doing any real good.* 

The French quarantine legislation is very prolix, although confined 
to three maladies — plague, yellow fever, and cholera. Among the 
precepts is frontier quarantine. For the regulation of maritime quar- 
antine, which apparently is the only form possible at the present day, 
the coast is divided into eleven districts, each with a medical officer 
and proper staff'. Each port has an office with agents and subordinates. 
The control is in the hands of district sanitary councils, who, with the 
prefects, prepare reports for the Minister of the Interior. 

Italy is the country in which quarantine is most rigid, being in the 
highway to the Levant and India, although cholera almost always 
travels in one well-marked course — through Russia and Germany to 
Hamburg, and thence to England and France. The chief difference 
between the English system and strict quarantine is that ours is only 
rigidly enforced in times of special danger. It has therefore a chance 
of being loyally carried out, whereas quarantine is a continual vexatious 
obstruction and is frequently evaded* 


A. Bacteriological Methods : Errors to which these methods are exposed — 
Conditions to be observed — Detennmation of the Antiseptic Value — L Of 
Antiseptics in Solution — Wynter Blyth's Method for Sewage Antiseptics — 
Precautions necessary in these Tests — II. Of the Vapours of Volatile Liquids 
— Chamberland and Klein's Methods — III. of Gaseous Antiseptics. Deter- 
mination of the Germicidal Value : Relative Value of the Culture and 
Inoculation Tests — Examination of Disinfectants in Solution — Dilution 
Methods of Sternberg and Wynter Blyth — Thread Methods — Examination 
of Gases and Vapours — Fischer and Proskauer's Apparatus. B. Chemical 
Methods : Necessity of Analysis — Requirements. Chloride of Lime : Pre- 
paration of Standard Solutions and Titration. Sulphurous Acid and 
Sulphites. Peroxide of Hydrogen. Boric Acid. Metals. Permanganate. 
Phenol : Estimation of Water— Of Phenol by Bromine— Of Cresol — Examina- 
tion of Tar Oils — Carbolic Powders — Hager's Glycerine Test — Carbolic Soaps 
— Salicylic Acid and other Preservatives in Foods— Tests for Thymol, Naph- 
thol, &c. — Medicated Wools. 

In order to ascertain the antiseptic or disinfectant value of a given 

substance it is necessary to ascertain its effect upon known organisms 

* Sanitary Congress, Glasgow, 1883. 


under known conditions. In dealing with commercial products it is 
always desirable to ascertain their chemical composition and the rela- 
tive amount of the active ingredients present. A full analysis is in 
many cases of value, since there is abundant evidence for the belief 
that when an active substance is mixed with others the germicidal 
value of the mixture is modified. It is impossible to explain the 
extraordinary results which have been obtained when two or more 
chemical substances have been used together in any other way. The 
probable cause of this phenomenon is the selective afiinity which 
different micro-organisms exhibit towards different chemical com- 
pounds, so that, in addition to the cumulative effect of the several 
constituents present, there is a further toxic effect produced by their 
simultaneous action. 


The principles which underlie the methods employed in the bac^ 
teriological investigation of the value of antiseptics and disinfectants 
are of extreme simplicity. The conditions under which the deter- 
minations of efficiency are made have, however, a very great influence 
in modifying the results obtained, and unfortunately sufficient care 
has not, in the past, been taken to specify the conditions of experi- 
ment with exactness, nor has it been recognised that the relative 
values given for the efficiency of antiseptics and germicides are only 
to be accepted for the given experimental conditions. While the 
experimental methods employed have had general resemblance, they 
have varied infinitely in details, so that the results obtained by different 
observers are very rarely strictly comparable. The danger of neglect- 
ing the conditions is especially evident when attempts are made to 
apply certain experimental results to the actual practice of disinfection. 

The earliest investigations were chiefly directed to ascertain the 
antiseptic value of various agents by observing their preservative 
action on putrescible animal and vegetable infusions. To the in- 
fusions, sterilised by boiling, various proportions of the antiseptic 
were added, and the dose necessary to prevent putrefaction, or the 
period during which putrefaction was averted, was noted. The in- 
fusions were exposed to the air and compared with similar infusions 
untreated with the antiseptic. The materials used as tests were very 
various such as beef-broth, milk, urine, infusions of hay and turnip, 
or pastes made of bread, potato, <fec. The occurrence of smell and 
turbidity indicated the failure of the antiseptic to prevent decomposi- 
tion. The converse experiment, which was a crude attempt to 
determine the germicidal value of the disinfectant, was also employed. 
A fluid in which putrefaction was already well established was treated 


with the antiseptic in known proportions for a known time, and drops 
of the putrescent fluid were then used to infect fresh sterile, but 
putrescible, media. If these materials decomposed it was evidence 
that the antiseptic had failed to sterilise the original fluid. The errors 
to which these methods are exposed are — 

1. An unknown mixture of micro-organisms is experimented with. 
It has been abundantly shown that an antiseptic has very varying 
effects on varying microbes. 2. The presence or absence of spores in 
the inoculating mixture is unknown. 3. When the inoculation is left 
to aerial contamination the time of infection is not known. 4. The 
infecting mixture may not be identical in the experimental and control 
media, 5. Odour and turbidity cannot always be relied upon to 
indicate the first occurrence of microbic growth. 6. In conducting 
experiments in which the already putrescent fluid is used to inoculate 
fresh media it is impossible, since it is not known what varieties of 
organisms are present in the inoculating fluid, to be sure whether the 
secondary growths are caused by the inoculation or are the result of 
accidental contamination. Koch in his classical researches on the 
value of antiseptics pointed out these objections, and insisted that the 
experiments should be made with pure cultures of microbes, whose 
condition as to spore formation was accurately known and which could 
be used to artificially inoculate the test fluids with a known organism. 
Many pitfalls have since been discovered, but accurate experimental 
work dates from these researches. 

The bacteriological examination of antiseptics and disinfectants is 
directed to ascertain — 

1. What retarding or inhibitory influence the agent exercises on 
the growth of a specific micro-organism — i.e., what is its antiseptic 
power. 2. What effect it has in diminishing the virulence of patho- 
genic germs. 3. In what dose and in what time it will cause the 
death of the microbe ; what is its germicidal value. Modifications of 
virulence under the action of antiseptics, though most important, have 
only been determined for a small number of micro-organisms. For 
practical purposes the desirable end is to cause the death of the 
infective agent, not simply to modify it. The experimental methods 
vary according to the physical condition of the disinfectant, whether 
it is employed as a solution or as a gas. Though solid antiseptics aro 
employed it is only after solution that they are effective. The relative 
efficiency of antiseptics and disinfectants is expressed in terms of the 
dose and the time of action required to produce a given effect. 



I. Examination of Soluble Antiseptics in Solution. — (a) A series of 
flasks or test-tubes containing suitable culture fluids is prepared. To 
certain of these flasks known quantities of the antiseptic to be tested 
are added, while others are left as control flasks. After sterilisation 
the flasks are inoculated with the test organism and placed under 
suitable and similar conditions of temperature, aeration, &g. If the 
maximum antiseptic power is to be measured, then the conditions 
under which the flasks are placed must be those most favourable to 
the growth of the organism. As the only variable factor in the two 
series of flasks is the presence or absence of the antiseptic, any retarda- 
tion or inhibition of growth must be due to this variant. The 
occurrence of growth is determined by changes in the appearance 
of the media and by microscopic examination. (6) Wynter Blyth * 
suggested a method, intended chiefly to gauge the value of an, 
antiseptic for sewage purification, in which the proportion of microbes 
remaining alive after a given time of action of the antiseptic is esti- 
mated by culture and enumeration of colonies. Sewage or sewage- 
contaminated water is treated with a known proportion of the 
antiseptic, and at varying periods known volumes of the mixture are 
withdrawn and inoculated into definite volumes of liquefied gelatine 
medium. After thorough mixing plate cultures are made in Petri 
capsules. The capsules are placed under suitable conditions, and the 
number of colonies which develop are counted. If parallel experi- 
ments are made with two or more antiseptics the relative efficiency is 
in inverse proportion to the number of colonies found in the cultures. 
In this method it is assumed that the number of organisms inoculated 
is approximately equal. The plan has the usual disadvantages attach- 
ing to the gelatine plate method. 

Precautions. — If the antiseptic is volatile the culture fluids must be 
first sterilised by heat, and then the antiseptic added by means of a 
sterilised pipette. It must not be assumed that because growth does 
not appear so readily in the flasks containing the antiseptic as in the 
control, that therefore the proportion of antiseptic is sufficient to 
arrest growth. The flasks should be kept for not less than two weeks 
{Sternherg), as after long periods of retardation the restraining power 
often breaks down and copious growth takes place. The principal 
factors which cause variations in the efficiency of the antiseptics are — 

(1) Change in tlie Microbes experimented with. — Certain microbes 
have a peculiar tolerance towards certain antiseptics— e.<7., B. typhosus 
and iodine trichloride. Others are much aflTected by the acidity or 
* Proc. Roy. Soc, 1886. 


alkalinity of the medium, and the change in reaction due to the added 
antiseptic may be the cause of variation. 

(2) Change in the Medium. — A diminution in the nutritive value of 
the medium will apparently increase the antiseptic power. The chief 
eflfect of change of medium is, however, due to changes which occur 
in the chemical reactions between the antiseptic and the constituents 
of the medium. All antiseptics which form precipitates with albumens 
have their efficiency diminished when an albuminous fluid is employed 
— e.g., HgClj, AglsTOg, &c.; and, similarly, any substance which by 
precipitation diminishes the available amount of soluble antiseptic 
present — e.g., NaCl with AgNO^, or HoS with HgClo — will greatly 
diminish the apparent activity of the agent. 

(3) Change of Temperature. — This factor acts in two opposite direc- 
tions. An increase in temperature up to the optimum temperature 
of growth of the microbe is favourable to the micro-organism, but 
the rise of temperature also increases the activity of the antiseptic. 
Which factor will prove most active can only be determined ex- 

II. Examination of the Vapours of Volatile Fluids. — The principle of 
the methods employed is similar to that described for solutions. 

(a) Chamberland's Method.* — A U-tube similar to those used for 
anaerobic cultures is employed. Into one limb the volatile fluid is 
aspirated, into the other the inoculated culture medium. The tubes 
are then sealed. The space above the fluid becomes saturated with 
the antiseptic vapour. The occurrence of growth is determined as 

(h) Klein's Met/iod.i — Short and wide tubes are prepared containing 
sterile agar medium with the usual sloping surface. The volatile 
antiseptic is placed on the side of the tube opposite the agar, and the 
excess runs to the bottom of the tube. The agar is then inoculated in 
its upper part, well away from the fluid and the tubes, tightly plugged 
and, if necessary, capped with an india-rubber cover, and kept at a 
suitable temperature. The efficiency of the antiseptic is evidenced by 
the absence of growth. 

III. Examination of Gaseous Antiseptics. — The methods will be 
described when dealing with the germicidal value of disinfectants. 


Principle of the Methods. — The disinfectant is allowed to act for a 
known time in a known strength on a pure culture of a micro-organism. 
The disinfectant is then removed, and the death or continued vitality 

* Ann. Inst. Pasteur, vol. L, p. 163. 

t BrU. Med. Joum., 1894, vol. i., p. 375. 


of the organism determined by (1) the capacity to produce fresh cul- 
tures, or (2) the power to produce a pathogenic effect when inoculated 
into susceptible animals. The objects to be attained are : — (1) The 
perfect exposure of the organisms to the action of the disinfectant. 
In order to ensure this condition the organisms should be in suspension 
or exposed in a very thin layer, and care should also be taken that 
the microbes are not coated with any layer, such as oil, which would 
mechanically prevent the action of the disinfectant. (2) The perfect 
removal of the disinfectant from the organisms whose vitality is to be 
tested. The various modifications in the experimental methods are 
chiefly directed to this end. Seppert has shown the great difficulty 
that there is in freeing the organisms from adherent material, and also 
the enormous influence that infinitesimal doses of disinfectant may 
have in retarding or hindering growth. This is especially marked 
with regard to the germination of spores. Seppert experimented with 
anthrax spores and mercuric chloride, and demonstrated the different 
results obtained according as the mercuric chloride was simply washed 
away or removed by precipitation with ammonium sulphide. He also 
showed that the amount of mercuric chloride required to prevent the 
development of spores which had been exposed to the action of the 
disinfectant was very much less (only 1 : 2,000,000) than the proportion 
required to produce the same effect on spores which had not been so 
exposed, and that the longer the exposure the less was the amount 

Relative Value of the Culture and Inoculation Tests in the Deter- 
mination of the Vitality of the Disinfected Organisms. — Opinions differ 
very considerably on this point. There can be little doubt that for 
the determination of the continued vitality of the organism the culture 
test is the more delicate, and for this reason, as well as for the con- 
siderations of economy and convenience, it is the one usually employed. 
For determining alterations in the virulence of the microbes, the in- 
oculation test is the only one available. The great objection to the 
animal inoculation test is the fact that exposure to the disinfectant so 
modifies the virulence of the organisms that they no longer produce 
their pathogenic effect, though they retain their vitality. There is 
no certainty that these non-virulent organisms may not give rise on 
germination to virulent growths, and therefore, for practical purposes, 
the death rather than the alteration of the organisms is to be desired. 
An animal which has been used for an inoculation test cannot be 
employed a second time even if it has apparently not suffered any ill 
effects, as a condition of insusceptibility, a vaccination, may have been 
produced by the first inoculation. 

Examination of Disinfectants in Solution. — Dilution Methods. — There 


are several methods, varying in detail, in which, after exposure of the 
organisms to the action of the disinfectant, a small portion of the cul- 
ture is removed and inoculated into a relatively large volume of a 
nutrient medium. The dilution thus brought about is trusted to 
reduce the amount of the disinfectant carried over below the amount 
which would cause inhibition of the growth. If thought advisable, a 
second inoculation, with consequent further dilution, may be made 
from a primarily infected culture. It is obviously important that 
fluid media should be used for the culture test, or otherwise the re- 
moval of the disinfectant is not secured. 

(a) Sternberg's Method. — A known volume (5 c.c.) of the standardised 
disinfectant is added to an equal volume of a fluid (bouillon) culture of 
the micro-organism. After exposure for a given time a small portion 
of the mixed culture is withdrawn and inoculated into a suitable 
culture medium. The results are calculated as produced by a disin- 
fectant of one half the strength of the solution added to the culture. 
Either the time of exposure or the strength of the solution can be 
made the variable factor. 

(6) The Drop Method ( Wynter Blyth). — Sterilised distilled water is 
infected with the test organism, and measured volumes of the infected 
water are added to known volumes of the disinfectant. After a given 
time a drop of the mixture is added to 10 to 20 grammes of liquefied 
gelatine medium, and the growth watched. Bouillon is a more suit- 
able medium, as many pathogenic germs grow slowly at temperatures 
at which gelatine remains solid and retains its distinctive advantages. 
Bouillon has also been shown in Miquel's experiments to give greater 
opportunity for the growth of organisms whose vitality has been re- 
duced than the solid media. If it is desired to use micro-organisms 
from cultures in solid media, the growth is scraped off with a wire 
And suspended in sterile distilled water. Such suspensions, filtered to 
remove flocculi, are employed advantageously, because the disturbing 
effects of varying media and the presence of precipitates are avoided. 

The Thread Metliod. — This is often known as Koch's metliod, as it 
was employed by him in examining the action of antiseptics on the 
spores of Bacillus anthracis. Sterilised silk threads were soaked in 
cultures containing anthrax spores (or, better, suspensions of spores 
in sterile water) and dried. The threads were allowed to hang in the 
disinfectant for the desired time and afterwards withdrawn, washed 
in sterile water, and inoculated either into animals or fresh nutrient 
media. Koch employed solid media for his inoculations. This method 
ias been much used, and possesses the advantage that the disinfectant 
can be got rid of by washing. If fluid media are employed for the 
test cultures it possesses also the advantages of the dilution methods. 



When employed for non-spore-bearing organisms the intermediate 
drying should be omitted, as that itself will diminish the vitality 
of many organisms in the vegetative form. Suspensions in sterile 
water are preferable to fluid cultures in which to soak the threads, as 
the (often albuminoid) medium forms a coating when dry which 
protects the organisms. In all cases control experiments must be 
made in which threads are treated^ just as are the test threads, except 
that sterile water is substituted for the disinfectant. Instead of 
threads platinum wires have been employed, and Blyth has suggested 
the use of small plugs of sterilised cotton wool attached to capillary 
glass rods by means of sealing wax. There must be some difliculty 
in securing efficient sterilisation of these mops. 

Examination of Gases and Vapours. — The method of Chamberland 
described above is equally convenient for the determination of the 
germicidal action of the vapour of essences, volatile oils, &c. Instead 
of an inoculated medium a suspension of a given microbe is aspirated 
into one limb of the tube, and after exposure for the desired time a 
drgp of the culture is withdrawn for inoculation. It must be remem- 
bered that unless the gas or vapour is soluble in water only the surface 
is exposed to the action of the disinfectant. When it is not required 
that the proportion of a gaseous disinfectant present should be known, 
or when the eflfect of a saturated atmosphere is to be tested, the micro- 
organisms, either on threads, or in very thin layers on sterile cover 
glasses, or on sterile filter paper which has been dipped into cultures 
or water suspensions and allowed to dry, may be exposed under a bell 
jar to the action of vapour evolved from a capsule of the volatile 
disinfectant also placed under the jar. Test-tubes Avitli bulbous ends, 
such as are used for potato culture:-;, may also be conveniently employed, 
the disinfectant being placed in the bulb. The threads, cover glasses, 
&c., are used to inoculate culture media either directly or after 

Fischer and Froskauer^s Method* — These two observers made a 
series of very complete investigations on the action of several gaseous 
disinfectants, including sidpliurous acid and the halogens. Their 
apparatus consisted of a 20-litre very wide-mouthed jar, through 
whose stopper tubes for the delivery and exit of gas were passed. 
Both tubes were provided with taps, and the exit tube was furnished 
with a series of absorption bulbs. A thermometer also passed through 
the stopper. The centre of the stopper was itself perforated and 
fitted with a large india-rubber cork, through which passed a glass 
rod, carrying a series of glass shelves on which the objects to be 
disinfected could be placed. Such an apparatus permits of the ex- 
• Milt, ausdem K. Gesund., Bd. II., 1884. 


posure of test objects to the action of the disinfecting gas under the 
most diverse conditions, and also allows the amount of the gas present 
in tlie apparatus to be determined. 

Most of the conditions wliich affect the determinations of anti- 
septic and germicidal values have been already considered, but 
there is one factor which is not under experimental control, and 
which imparts an element of uncertainty into the results. This 
factor is the variation in vitality and resistance of different specimens 
of the same micro-organism. In any culture there is a rather wide 
range of variability in the individual organisms, and this range of 
variability is increased if the cultures are not of the same age and 
grown under the same conditions on the same medium. The age 
and nature of the culture should always be specified, and this 
element of variability eliminated so far as possible by multiplying the 
experiments. It is obvious that the methods detailed above must be 
varied as the problems to be solved differ ; but the principles to be 
kept in view, and which have been insisted upon, are constant ; while 
the errors to be avoided are also very similar in every investigation. 


As already pointed out, a full chemical analysis of a given disin- 
fectant is desirable, owing to the influence of foreign substances upon 
its germicidal value. In many cases in which the active ingredient is 
volatile, it is necessary to test from time to time the chemical strength 
of the material, as there have been several instances in which neglect 
of this precaution has allowed the use of a disinfectant which has been 
found to be of no valne in preventing the spread of the infection 
through deficiencies in its activity having arisen either by storing or 
the culpability of the vendor. The methods of analysis obviously 
depend on the kind of substance to be employed, and may frequently 
involve much labour and skill. It is extremely important, however, 
that all disinfectants should be purchased on analysis, and that samples 
should be taken from bulk after the order has been executed, in order 
that the medical ofiicer may be assured that the material is equal in 
strength to that which has been prescribed. It would exceed the 
scope of this chapter if all the methods which might be of service were 
described at length. A selection has therefore been made of some of 
the quantitative tests which may be of use in identifying an unknown 

For any exact analysis, a laboratoxy, and such special skill, know- 
ledge, and training as no engineer or medical man can possess, is 
indispensable; hence such questions should be referred to a competent 
chemist. But there is always an advantage in being able to quickly 


and roughly determine factors like the strength of chloride of lime, «kc. 
It has already been pointed out that disinfection in ignorance is almost 
worse than no disinfection at all. 

In the following sketch for the simplest processes for testing the 
most important disinfectants, a knowledge of elementary quantitative 
analysis is assumed. Further details will be found in the various 
manuals on analysis. The following is a typical example of methods 
of procedure : — 

Chloride of Lime. — As already explained (p. 63), the available 
chlorine is that existing as hypochlorite, Ca(C10)o ; this easily breaks 
up into chloride, CaClo, and free oxygen, O^. The usual way of esti- 
mating it is by standard solutions of iodine and arsenlous acid, using 
starch as an indicator. The latter is not permanently blued until all 
the arsenious acid has been oxidised to arsenic acid. 

All volumetric solutions are usually made decinormal — i.e., one-tenth 
equivalent in grammes of the active agent in one litre ; then 1 c.c. is 
equivalent to 1 c.c. of another. 

Iodine Solution. — Dissolve 12 "65 grammes of iodine, mixed with 
about 20 grammes of potassium iodide, in a litre of water. 

Arsenious Solution. — 4*942 grammes of pure arsenious oxide and 
20 grammes of sodium bicarbonate are dissolved in a litre of water. 

Take 10 grammes of chloride of lime, triturate it in a mortar with 
successive small quantities of water, and transfer the whole gradually 
through a funnel into a stoppered litre flask. For each determination 
take out 10 c.c. of the well-shaken turbid fluid (to decant the clear 
solution gives a lower result — Fresenius), equal to a decigramme of the 
powder. Add from a burette the arsenious solution in slight excess — 
i.e., until a drop ceases to produce a blue spot on ozone paper (KI and 
starch). Then add fresh starch paste, and run in iodine solution from 
another burette until there is a slight permanent blue colour. The 
number of cubic centimetres of iodine solution required gives the 
number of c.c. of arsenious solution that have been added in excess ; 
subtract this from the total added, and the number of c.c. of the 
standard arsenious solution which are equivalent to a decigramme of 
the chloride of lime is obtained. 

Each c.c. of the decinormal arsenious acid is equal to yj^^tj- of 
an equivalent of available chlorine, or -00354 gramme. 

The iodine solution should have its strength determined by the 
arsenious acid before each series of experiments. It keeps fairly well 
in the dark. 

The same method can be used for the examination of chlorinated 
soda and potash, Hermite liquid (p. 67), bromine and iodine water, 
tincture of iodine, chlorine water, and indeed most oxidants. 


Sulphites and Sulphurous Acid. — The solution must be very dilute 
containing not more than 0'05 per cent, of SOg {Bun8en)y then iodine 
converts sulphurous acid into sulphuric. If sulphite powders are 
examined the method is exactly as with chloride of lime, omitting the 
arsenious solution, but adding starch paste and running in iodine 
solution until the permanent blue tint is obtained. 1 c.c. of iodine 
= -0032 gramme of SOo. 

The same process answers for most reducing agents, such as sul- 
phuretted hydrogen, &c., but not for ferrous sulphate, which should 
be determined by standard permanganate. 

To test for the presence of sulphites in food, two portions should be 
strongly acidified by dilute pure sulphuric acid, and over each a piece 
of paper moistened with lead acetate should be suspended. To one 
should be added some pure granulated zinc, so as to obtain a slow 
evolution of hydrogen. If much frothing occurs, water must be added. 
The two are left for half an hour in a warm place. If the lead paper 
be blackened only over the one containing the zinc, it proves the pre- 
sence of sulphite ; if both papers be blackened, the blackening is due 
to other sulphur compounds, and the test is worthless. 

Peroxide of Hydrogen is marked in commerce " 10 or 20 volumes," 
meaning the number of times its volume of oxygen that is given off 
when it is treated with peroxide of manganese. An easy way of 
ascertaining this is as follows : — 

A flask with cork and delivery tube is arranged to deliver the gas 
into a graduated measuring tube holding 200 c.c. filled with water 
and inverted in a basin or pneumatic trough. 10 c.c. of the hydrogen 
peroxide solution are measured into the flask. About a gramme of 
finely-powdered manganese dioxide is wrapped in a piece of paper, 
slipped into the flask, and the cork at once replaced. On shaking, the 
available oxygen is evolved. By warming the flask the last of the 
oxygen is removed, and is then measured. It can, of course, be calcu- 
lated into weight. A rough idea of the quantity may also be obtained 
by adding to the diluted solution in a test-tube a few drops of 
potassium dichromate, then dilute sulphuric acid and ether. The 
intensity of the purple colouration of the ether layer is compared with 
that produced by a sample of known strength. This cannot be recom- 
mended except as a qualitative test. 

Boric Acid. — A quantitative determination is tedious, but its pre- 
sence in milk, &c., may be ascertained as follows : — Evaporate a large 
measured quantity (say 250 c.c), rendered alkaline by lime water to 
dryness, and burn to ash. Warm the ash for some time with a little 
water containing a drop of ammonium chloride, and filter. Acidulate 
the filtrate just faintly with hydrochloric acid, and spread it on a sheet 


of turmeric paper specially made as follows : — Digest turmeric root 
with rectified spirit, filtei', float a» sheet of writing paper oa the extract, 
then drain and dry it so that it has a uniform clear yellow coating. 
The spot is carefully dried over a water-bath ; if boric acid be present 
there will be a rose-red colouration, turned dark dull blue by weak, 
soda solution. 

A few metals can be determined by volumetric processes, but as a 
rule, methods of precipitation and weighing are adopted. It will be 
rarely necessary or feasible to undertake these, as solutions of known 
strength can easily be made by dissolving the calculated quantities of 
the salts bought on a guarantee or on the analysis of a chemist. 

Permanganate (Condy's Fluid). — A known volume of a decinormal 
solution of oxalic acid is placed in a beaker or porcelain dish, rendered 
strongly acid with dilute sulphuric acid, and the permanganate solu- 
tion, properly diluted, run in from a burette until a permanent pink 
tinge is produced. The reaction is — 

5H2C2O4 + KgMnaOs + H2SO4 = K2SO4 + 2MnS04 + IOCO2 + 8H2O. 

Therefore 5 equivalents of oxalic acid require for oxidation 1 equi- 
valent of permanganate, equal to 5 atoms of aA'ailable oxygen. 

Phenol. — Water is estimated by shaking the sample in a graduated 
tube with half its volume of a saturated solution of common salt. 
The diminution of volume of the phenol indicates the amount of water 
present. "Calvert's No. 1" contains none, crude acids often contain 
10 to 17 per cent. Anhydrous cresol shaken up with three volumes of 
brine gives an increase of volume of about 5 per cent. If the cresol 
contains water, its volume either does not alter, or decreases slightly. 

To Determine the Phenol. — Shake up bromine with water at 20° C* 
To determine the phenol-equivalent of the bromine water, a sample of 
Calvert's No. 1 acid (crystals) is boiled for a short time to remove 
traces of moisture, 0-25 gramme weighed into a well-stoppered flask 
and dissolved in 100 c.c. of water, the bromine water run in from a 
stoppered burette, with constant shaking, until there is a good excess, 
as shown by the colour. After half an hour's standing, if the excess 
has disappeared, more bromine must be added, and the mixture again 
shaken and allowed to stand ; the total amount added must be care- 
fully noted, excess of potassium iodide is added, and the amount of 
liberated iodine ascertained by standard thiosulphate and starch in the 
well-known manner. This free iodine corresponds to the bromine in 
excess ; deduct this from the total bromine added, and the amount of 
bromine water necessary to precipitate 0*25 gramme of pure phenol is 

* Such a solution keeps better than water saturated with bromine in the cold, 
and may be preserved in well- stoppered bottles in the dark. 


obtained. It is then easy to calculate the phenol-equivalent of each, 
cubic centimetre of the bromine solution. 

CeHs.OH + 3Br2 = CcHaBrg.OH + 3HBr. 

The operation repeated with the sample under examination gives the 
phenol strength. 

Samples containing cresol and higher phenols would require pro- 
portionately less bromine, so the result would be lower than the 
truth, if the bromine equivalent is calculated to phenol. Another 
process consists in determining the solidifying point of a mixture by 
cooling it in a narrow tube and adding a minute crystal of pure 
phenol to aid the solidification. The melting point is then compared, 
with ready-made mixtures of known composition (or with a table). 

It is possible to collect the tribromo-precipitate on a filter paper. 
Tribromophenol is crystalline, tribromocresol and the others are liquid ; 
hence the latter soaks into the paper, and the two can be separately 
weighed. The liquid portion should be calculated as cresol and higher 

Fractional distillation of the phenoloids gives doubtful results as 
their boiling points are too near one another. 

Tar Preparations. — The ingredients of these may be divided into 
four groups : — 

1. Neutral bodies not combining with acids or alkalies,, divided 
into — 

(a) Light oils, containing benzene and the homologues. 
{h) Heavy oils, containing naphthalene, anthracene, &c. 
The antiseptic value of these is slight. They are classed as neutral 
tar oils. 

2. Basic bodies, combining with acids — e.g., aniline, pyridine, <fec. 
As their antiseptic value is high they may with advantage be present 
in disinfectant fluids. The commercial importance of aniline has led 
to this group being extracted in making phenol and cresol prepara- 
tions. Hence there has been a reaction in favour of crude coal-ttir 
preparations, instead of the purely phenol compounds that were 
formerly almost exclusively in vogue, although the neutral bodies in 
the former are undoubtedly of little value. 

3. Pitenols, soluble in alkalies, but not really acid bodies (p. 149). 
The valuation of these preparations is based on the proportions of 
these constituents. 

A. 10 c.c. of the oil are taken in a graduated tube, 20 ac of 10 per 
cent, caustic soda added, and the whole well shaken, and allowed to 
stand. The phenoloids dissolve, while the neutral (and basic) sub- 
stances collect as an oily layer; below, if they are heavy oils; at the 


top, if they are light oils. If they will not separate distinctly, which 
often happens, add 10 c.c. of petroleum ether and shake, measure the 
amount of the mixture and subtract the ether. The result is only 
approximate, but for ordinary purposes this method is considered 
sufficient, the volume obtained being returned as the neutral tar oils 

B. For a more exact examination a larger quantity must be taken, 
50 or 100 grammes of the original liquid, treated with soda as 
above, and the two liquids separately examined, after measuring their 

(a) The portion insoluble in soda is evaporated below 100° C. to 
remove the ether ; naphthalene and anthracene may crystallise out on 
standing, and may be identified by their melting and boiling points. 
The liquid which will not crystallise is washed in a graduated tube with 
20 per cent, sulphuric acid to remove the bases as sulphates. Notice 
again the diminution of volume (result only approximate). The acid 
solution is distilled with aqueous potash ; the bases (aniline, pyridine, 
&c.) come over and can be tested. If the quantity allows, dry them 
by fused calcium chloride, determine their boiling and melting points, 
their chemical reactions, and the nature of their platinum double salts. 
The portion insoluble in all reagents can be tested by its physical 

(b) The fraction soluble in soda, containing the phenoloids, is frac- 
tionally precipitated by successive small quantities of dilute sulphuric 
acid, whereby the carbolic acid is concentrated in the first fraction ; 
then the melting points of the several fractions are taken, as above 

Caxbolic Powders. — In the case of powders made with lime, or others 
in which the phenol exists in combination, neither direct distillation, 
nor extraction with ether, give a correct result unless the powder is 
first acidified. Allen mixes 50 grammes in a large mortar with 5 c.c. 
of water, and drops in gradually with constant stirring, so as to keep 
down the heat, 50 per cent, sulphuric acid. The addition, which takes 
some hours, is continued till a fragment of the powder shows an acid 
reaction when moistened with water. If the mixture be pasty, it 
must be triturated with sand to make a granular powder. After 
standing covered for two hours, it is transferred to a large Soxhlet 
tube and extracted with ether or benzene. On distilling ofi" the 
solvent below 110° C, the crude tar products are left, and can be 
further tested. 

To distinguish between preparations made from wood-tar and from 
coal-tar is comparatively easy ; in mixtures the identification of the 
source (shale oil, blast furnace oil, «kc.) becomes more difficult. 


1. Coal-tar acids coagulate collodion, B.P., wood creosote does not. 

2. A neutral aqueous solution of ferric chloride gives with phenol a 
deep violet colour, with wood-creosote a yellowish or greenish-brown tint. 

3. Hager's Test. — Thirteen volumes glycerine are diluted with 1 
volume water. One volume of the sample to be tested is well shaken 
in a stoppered burette with 3 of the diluted glycerine, and allowed to 
stand. If the creosote be pure, the volume will remain unchanged. 
If reduced, the glycerine layer is drawn off and the reinaining creosote 
again shaken with 3 volumes of the dilute glycerine, and the volume- 
again observed. The undissolved portion includes the wood-creosote, 
but may also contain products from shale or blast-furnace oil ; the 
chief distinction lies in the odour. The soluble portion may be diluted? 
with water, the coal-tar acids extracted with chloroform, and the latter 
separated and distilled off. So separated, the phenoloids from blast- 
furnace and shale oils give with ferric chloride a violet-blue colour 
changing to brown, instead of a permanent deep violet, as with ordi- 
nary phenol. 

Sulphuretted hydrogen should be tested for with dilute sulphuric 
acid and lead paper. Powders containing it emit an offensive odour, 
and are usually excluded by the terms of the contract. Sulphites and 
hypochlorites can be determined as at p. 308. With lime bases, the 
determination of sulphurous acid is difl&cult. As sulphurous acid 
powders oxidise on keeping, it is important to ascertain not only the 
"available" sulphurous acid, but also the quantity oxidised to sul- 
phuric acid. 

It is impossible to give a general process for the detection or esti- 
mation of the multitude of organic bodies that have been introduced 
for sanitary purposes. It may be mentioned that in the above division 
of the tar preparations into acid, basic, and neutral bodies, the follow- 
ing substances will appear in the places indicated : — 

(o) With the neutral oils : Benzene, naphthalene, anthracene, vase- 
line, paraffins, pyrrol, essential oils, thymol, camphors, alcohol, ether, 
and neutral bodies generally. 

(6) With the bases : Aniline, pyridine, quinoline, ammonia, compound 
ammonias, and volatile alkaloids such as trimethylamine, nicotine, &c. 

(c) With the acids : Phenol, cresol, &c., resorcin, benzoic, and other 
aromatic acids, fatty and resin acids (distinguished by non-volatility 
and other physical characters ; resin soap gives a brown colour and is 
not coagulated by strong soda solution, thus differing from a fatty 

The specific gravity of crude carbolic acid should be between 1 -05 to 
1-065; if it is less it is most likely adulterated with light tar-oil, in 
which case the specific gravity is often between 1 04 and 1 04:5. 


Carbolic Acid in Soaps. — Five grammes of the soap are dissolved in 
warm water, and 20 or 30 c.c. of 10 per cent, caustic soda added. After 
cooling, the solution is shaken witli ether to remove any hydrocarbons 
(terebene, camphor, <kc.). The alkaline liquid is next mixed with 
saturated brine, which precipitates the soap and leaves the phenols in 
solution. It is then filtered, the soap again shaken up with brine 
and the washings added to the filtrate, and the liquid made up to 
1 litre. 100 c.c. of the solution ( = 0*5 gramme of the soap) are placed 
in a separator, acidulated with dilute sulphuric acid, and titrated with 
bromine water as at p. 310. 

Salicylic Acid and other Preservatives in Foods. — The articles are 
cut up if necessary, and extracted, first with two portions of cold, then 
with about three of boiling water, separating any fat by passing through 
a wet filter, or in some cases by allowing the whole to cool and removing 
the layer of fat. The volume of the aqueous liquid should not be un- 
duly large. Milk must be coagulated by a little acetic acid and gentle 
warming, then filtered and the whey examined. Solutions containing 
gummy or viscous matters, or colouring matters soluble in ether, can 
be precipitated by neutral acetate of lead filtered, the filtrate freed 
from lead by sulphuretted hydrogen, and the latter expelled by 
warming. The prepared filtrates should then be neutralised by soda, 
evaporated to a convenient bulk, acidified with hydrochloric acid, and 
extracted with ether in a separator. The ethereal solution, besides 
salicylic acid, will contain any phenol, cresol, benzoic and other aro- 
matic acids, thymol, essential oils, ethers, glycerine, perhaps bitter 
principles, resins, glucosides, alkaloids, and sugars in traces, lactic and 
vegetable acids. If acetate of lead has been used, the resins and 
bitters will have been removed. Distil oft' the ether, evaporate the 
residue at a gentle heat, dissolve in a measured volume of water, and 
divide into several portions. Notice the odour, taste, and appearance, 
a,nd apply special tests. If glycerine be sought for, neutralise with 
soda, again extract with ether, distil off the ether and evaporate; the 
nearly pure glycerine can be weighed and afterwards tested. 

In an aliquot part the salicylic acid can be determined by adding 
neutral ferric chloride cautiously (iron alum is more convenient), and 
imitating the colour in another tube by a standard solution of salicylic 

If phenol or resorcin be present, the comparison must be effected in 
alcoholic solution (absolute), with alcoholic ferric chloride. Thus even 
1 part of salicylic acid with 800 of phenol may be estimated.* In 
testing for resorcin H. Bodde f adds a few drops of sodium hypochlorite 

• A. Fajans, Chem. Zeitung, 1893, vol. v., p. 69. 
f Nederl. Tydschr. v. Pharm., May, 1889. 


(p. 63) to a watery or alcoholic solution of resorcin ; a violet colour, 
i-apidly changing to yellow, is produced. On wanning or adding excess, 
the liquid becomes dark brown. One part of resorcin in 10,000 of 
water will still show this reaction. Carbolic, salicylic, benzoic, and 
other allied acids do not give it, but may turn the liquid slightly 
yellow on warming. Pyrocatechol (p. 172) turns green, hydroquinone 
yellow and red. Another test is to first add liquor ammonite and then 
a few drops of the hypochlorite, when the liquid will give a reddish- 
violet colour, turning green on boiling. The colour is not taken up 
by benzene. The reaction is not shared by salicylic nor benzoic acid, 
nor by antifebrin (p. 185), but phenol gives a greenish-blue, partly 
soluble in benzene. The colours are changed to red by dilute sulphuric 

Messenger and Vortmann have found that strongly alkaline solutions 
of phenol, thymol, /S-naphthol, and salicylic acid admit of estimation 
by means of a decinormal thiosulphate solution, using starch as an 
indicator in the ordinary way. Each molecule of phenol consumes 
6 atoms of iodine, therefore the iodine consumed multiplied by 

„^- ^, ,- — ; — ' ^ . ,. K or 0-1235, gives the quantity of phenol. The 
759-24 (6 atoms iodine) * ^ J r 

process is as follows : — 2 grammes of the phenol are dissolved in water 

with about 3 grammes of caustic soda, and the solution diluted to 250 

or 500 c.c. 5 or 10 are measured into a flask, warmed to 60° C, and 

iodine solution added till the liquid is strongly yellow. On agitation 

a bright red precipitate will fall. After cooling, the liquid is acidulated 

with dilute normal thiosulphate to ascertain the excess of iodine. 

Thymol gives a brownish-red precipitate, and requires no heat. It 
requires 4 atoms of iodine, hence the multiplier is 0-2957. From 0-1 
.to 0-3 gramme is taken. 

^Naphtlwl gives a dirty-green precipitate ; the factor is 0*3784. 
The solution must be heated to 60° C. 

Salicylic Acid. — At 60° C. the bright red precipitate should not be 
formed until the iodine is in excess, and should be increased by acidu- 
lation. If too little alkali be present, a yellowish-white precipitate is 
formed ; in this case more soda must be added. The multiplier is 

In a mixture of two of these bodies, if the sum of their weights is 
known, as well as the iodine equivalent of the mixture, the amounts 
of the two constituents can be calculated. 

Formalin can be recognised in foods by distilling and proving the 
presence of a volatile aldehyde in the distillate by means of a magenta 
solution bleached by sulphurous acid. 

• Berichte, 1890, p. 2753. 


Medicated Wools. — Mr. Hoseason, in a recent paper on medicated 
cotton wool dressings,* drew attention to the immense variation in 
the strength of these preparations as found in commerce. The method 
of analysis consists in shaking weighed quantities (10 grammes) of the 
wools with water (1 litre), and determining the amount of the effective 
constituent in the following way : — 

1. PJienol, by the volumetric bromine process (p. 311). 

2. Boric Acid, by evaporating one-fortieth (25 c.c.) of the solution 
to dryness with 5 c.c. of a strong solution of sodium carbonate, the 
latter being previously standardised. The loss of carbonic acid was 
estimated by weight in a modification of the usual COg apparatus. 
The boric acid was thus determined by difference. 

3. Mercuric CMoride. — Scherer's method with hydrochloric acid and 
decinormal thiosulphate is inapplicable if the quantity of mercury is 
small. A colorimetric method based on the depth of the brown colour 
with sulphuretted hydrogen may be used. Some results obtained with 
commercial antiseptic wool dressings are as follow: — 

Carbolic, in five samples : 1-06, 1"07, 0*69, 0*25, 5*08 per cent. 
Boric, in five specimens : 36, 21 "6, 27*1, 15"8, 14-4 per cent. 
Corrosive Sublimate, in two : none, and 1 in 8,000 to 9,000. 

* Chem. and Drug., Feb. 18, 1893. 




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Salicylic and Benzoic Acids. 

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Soc, xxvi., 184, 1877. 
Downes and Blvint. Influence of Light on Protoplasm. Ibid., xxviii., 199, 1878. 
Tyndall. Influence of Light on Organic Infusions. Ibid., xxviii., 1878. 
Tjrndall. Arrestation of Infusorial Life. Nature, xxiv., 466, 1881. 
Jamieson. Infl. of Light on Bacteria, /ftfrf., xxvi., 1882. 
Duclauz. Infl. de la Lumi^re du Soleil. Comptea Rendua, c. 119, and ci. Aug. 5, 

Arloing. Infl. de la Lumi^re sur Bacillus Anthracis. Ibid., Feb. 9, Aug. 24, 

and Aug. 31, 1885. 
Downes and Blunt. Answer to Criticisms. Ibid., xl., 242, 1886. 
Roux. Action de la Lumiere et de I'Air. Ann. Inst. Pasteur, i. , 455, 1887. 
Gaillard. Influence de la Lumifere. Lyon, 1888. 
UflFelmann. Hyg. Bedeutung des Sonnenlichtes. 1889. 
FanzinL Azione della Luce. Rivista d'Igiene, 1889. 
Santori. La Luce. Boll. d. Accad. Med. di Roma, xvi., 1889-90. 
Momont. Ann. de I' Inst. Pasteur, vi., 21, 1892. 

Geissler. Wirkung des Lichtes. Cenlr./iir Bakteriol, xii., 161, 1892. 
Buchner. Einfluss des Lichtes. /bid., xi., 781 ; xii. 217, 1892; and Archiv. f. 

Ihjg., 1893. 
Marshall Ward. Proc. Roy. Soc, liii., 310, 1893. 
Procacci. Influenza della Luce Solare. Annali della Inst. d'Igiene di Roma, iii., 

437, 1893. 
Palermo. Azione della Luce Solare sulla Colera. Ibid., iii., 463., 1893. 
Khmelevsky. Influence of Light on Pyogenic Microbes. Brit. Med. Joum. 

No. 1,740, p. 71, 1894. 


Rapport de Commission sur les Appareils i disinfection par I'Air chaud. Revue 

d" Hygiene. Paris, 1881. 
Parsons. Disinfection by Heat. Report Med. Officer of Health to London Oovem- 

ment Board, 1881. 
Parsons. Extracts from do., 1886. 


H. Vogel. Food Preservatives. Deutsche Viertel.f. 6^. Ges., 402, 1880. 
Weber. On Food Preservatives. J. Amer. Chem. Soc, xiv., 1892. 
Bouvier. Le Lait. Paris, 1893. 


{Besides numerous references under Bacteriology.) 

Rivers Pollution Commission Reports, from 1868. 

Percy Frankland. Water Purification, its Biological and Chemical Basis. Tran». 

Inst. Civ. Engineers, 1886. 
Local Government Reports. London Water Supply: Effect of Filtration. 188& 

and following years. 
P. Frankland. Filtration of Water for Town Supply. Trans. Inst. Civ. E., 1886. 
Sir F. Bolton. Manual of London Water Supply. 



Plagge and Proskauer. Sand Filtration. Zdt. f. Hyg., ii., 401, 1887. 

Gartner. Hygienische BeschaffenheiJ des Trinkwassers. International Congress 
of Vienna, 1887. 

J. Koenig. Reinigung der Abwasser. Ibid. 

Fraenkel and Piefke. Filtration. Zeit.f. Hyg., viil, 1, 1890. 

Ste ilisation of Water. New York Med. Record, No. 1,023, p. 680, 1890. 

Lefftnann and Beam. Examination of Water for Sanitary and Technical Pur- 
poses. London, 1891. 

Floyd Davis. Handbook on Potable Water. New York, 1891. 

Eoux. -Analyse Microbiologiqne des Eaux. Paris, 1891. 

F. Fischer. Das Wasser. Berlin, 1891. 
Leeds. Potable Water. Boston, 1891. 

Crookes, Odling, and Tidy. Reports on London Water Supply. 

A W. Bennett. Vegetable Gi'owths as evidence of the Purity or Impurity of 

Water. Reprinted from St. Thomas's Hospital Reports, 1892. 
Lankester. Evidence on Royal Commission on Metropolitan Water Supply, 1892. 
Buchner. On River Water. Arch. /. Hygiene, 184, \892. 
Schmidt. Ditto, ditto, xiii., 247, 1892. 

V. & A. Babes. Filtration. Centr.f. BakterioL, xii., 132, 1892. 
Koch. Wasserfiltration and Cholera. Zeit.f. Hyg., xiv., 393, 1893. 
Koch. Cholera in I )eutschlaud. Ibid., xv., 89, 1893. 
DuclatLx. On River Water. Ann. de Vlnst. Pasteur, Feb. 25, 1894. 
Guinochet. iSpuration, Filtration, et Sterilisation des Eaux potables. Paris, 1894. 


G. P. Brown. Sewer Gas. Chicago, 1881. 

R. Warington. Nitrification and the Purification of Sewage by Soil. J. Soc. 

Arts, April, 1882. 
R. Warington. Same subject. British Association Meeting, 1884. 
Stevenson. Sewage Disposal. Soc. of Med. Off. of Health, 1884-5. 
Corfield and Parkes. Treatment and Utilisation of Sewage. London, 1887. 
E. Frankland. Report on the Purification of Sewage in England. International 

Congress of Hygiene, Vienna, 1887. 
Massachusetts State Board of Health. Experimental Investigations on the 

Purification of Sewage. Boston, 1888-90. 
Lepsius. Frankfort Commission on Sewage, 1891. 
Reports of Royal Commission on Metropolitan Sewage Discharge. 
Rawlinson (Sir H.) London Sewage. J. Soc. Arts, xxxviii., 65. 
Massachusetts State Board of Health. 24th Annual Report, 1893. 
Santo Crimp. Sewage Disposal Works, 2nd edition, 1894. 
Rafter and Baker. Sewage Disposal in the United States, 1894. 


Vaughan. "Tyrotoxicon." Report Michigan State Board of Health. Chicago, 

Squire. Companion to the British Pharmacopoeia with Supplement, 1890. 
Dolan. Pasteur and Rabies. London, 1890. 
■Williams. Antiseptic Dressings. Chemist and Druggist, 1892. 
Burdett. Hospitals and Asylums of the World, vol. iv., 1893. 



ABC process, 128. 

Aberdeen process for preservation, 269. 
Absynthol, 212. 
Acetanilide, 185. 
Acetate of aluminium, 132. 
,, of copper, 115. 
„ of lead, Basic, 134. 
,, of zinc, 113. 
Acetoarsenite of copper, 133. 
Acid, Acetic, 225. 

„ Anisic, 204. 
• ,, Arsenic, 134. 

„ Arsenious, 133. 

„ Benzene sulphonic, 159. 

,, Benzoboracic, 102. 

,, Benzoic, 195. 

,, Boric or Boracic, 99. 

„ Carbolic, 149, 316. 

,, Carbonic, 104. 

„ Chromic, 132. 

„ Cinnamic, 204. 

„ Cresylic, 160. 

„ Formic, 225. 

,, Gallic, 205. 

,, Hydrochloric, 69, 105. 

,, Hydrocyanic, 105. 

,, Hydronaphthoic, 180. 

,, Naphthalene-sulphonic, 177. 

,, Nitric, 87. 

,, Oleic, 227. 

,, Osmic, 144. 

„ Phenyl-propionic, 205. 

„ Picric, 181. 

,, Pyrogallic, 172. 

„ Pyroligneous, 173, 226. 

,, Salicylic, 198, 314. 

„ Sulpliobenzoic, 197. 

„ Sulphuric, 97. 

,, Sulphurous, 91, 234. 
Acids, Vegetable, 227. 
Air, Disinfeetion of, 245. 
Alcohol, 223. 

Alkalies, Salts of the, 106. 
Allen's fluid, 168. 
Altona, Sand filtration at, 14. 
Aliiminium, 127. 

,, acetate, 132. 

,, chloride, 131. 

,, sulphites, 132. 

Alumnol, 179, 254. 
Ambulances, 286. 
Amido- benzene, 184. 

Aminol, 184. 
Ammonia, 109, 182. 
Ammonium borate, 101. 

,, carbonate, 109. 

Amylamine, 184. 
Analysis, Methods of, 301. 
Andeer's lotion, 171. 
Anderson's patent, 117. 

,, process, 129. 

Aniline, 184. 

,, dye-s, 185. 
Animal charcoal, 10. 
Annidaline, 209. 
Anthracene, 148. 
Antipyrin, 188. 
Antisepsin, 102. 

,, Radlauer's, 112. 

Antiseptic, Definition of, 2. 

„ paper, 102, 140, 204, 255. 

,, tablets, 204. 

, , value. Determination of, 302. 
Antiseptol, 194. 
Antitoxine, 6. 
Apyonin, 187. 
Aristol, 209. 
Arsenic, 13.3. 
Arsenious solution, 308. 

,, sulphide, 134. 
Arsenite of potash, 133. 

,, of soda, 133. 
Asbestos, 13. 
Aseptic, Definition of, 2. 
Aseptol, 158. 
Ashes and cinders, 13. 
Ashpits, 231. 
Australian salt, 102. 


Baeillite, 162. 

Bacteria, Methods of dealing with, 5. 
Bacteriological methods of testing, 300. 
Bakehouses, 243, 282. 
Barlow's ventilator, 246. 
Barmenite, 102. 
Benzene, 148. 
Benzoic aldehyde, 197. 
Benzo-naphthol, 198. 

„ -paracresol, 198. 
Benzosol, 197. 
Berlinite, 102. 
Betol, 179, 199. 
Bichromate of potash, 132. 



Bird's process, 128. 
Bismuth, 144. 

,, subgallate, 144. 
Black ash waste, 128. 
Bleaching powder, 64. 
Blue vitriol, 115. 

Blyth's method of disinfection, 128. 
Bond's pellets, 140. 
Bone black, 10. 
Borates, 100. 

Tests for, 103, 309. 
Borax, 100. 
Bomeol, 212. 
Boroglyceride, 101, 227. 
Bradford's hot-air apparatus, 26. 
Bread, 275. 

,, Use of, for disinfecting walls, 292. 
Brockmann's salt, 102. 
Brom-acetanilide, 185. 
Bromidine, 72. 
Bromine, 70. 
Bromo-camphor, 211. 
Bromoform, 76. 

Bromo-naphthalene night lights, 72. 
Bromum solidifactum, 72. 
Budenberg's flesh steriliser, 271. 
Burnett's fluid, 110. 
Butter, 274. 
Bye-laws, Model, 290, 291. 

Cadaverine, 97. 

Calcium carbonate, 107. 

„ hydrate, 107. 

„ hypochlorite, 63. 

,, sulphate, 107. 
Calvert's powder, 154. 
Camphoid, 213. 
Camphor, 211. 
Candles, Iodine, 73. 

,, Sulphur, Kingzett's, 93. 

,, ,, Seabury's, 93. 

Carbide of iron, 117. 
Carbolic powders, 154, 312. 

,, soaps, 156. 
Carbolised gauze, 155. 
,, oil, 155. 

,, solution, 155. 

,, wool, 155. 

Carbon, 10. 

,, bisulphide, 98. 

,, dioxide, 104. 
Carbonate of ammonium, 109. 
„ of lime, 107. 

„ of soda, 108. 

Carbostyrile, 193. 
Carferal, 117. 
Caryophyllin, 212. 
Cats, 243. 

Cattle markets, 243. 
Cesspools, 240. 
Chamberland filter, 14. 
Charcoal, Animal, 10. 

Charcoal, Vegetable, 11. 

Cheese, 275. 

Chemical methods of analysis, 307. 

Chinese preservative powder, 102. 

Chloralum, 131. 

Chlorates, 69. 

Chlorides, 70. 

Chloride of aluminium, 131. 

,, of copper, 114. 

,, of lime, 63, 308. 

„ of zinc, 109. 
Chlorine, 57, 234. 
Chloroform, 76, 219. 
Chloronaphthalene, 180. 
Chlorophenol, 157. 
Chlorozone, 65. 
Cholera, Prevention of, 280. 
Chromium, 132. 
Cisterns, 237. 
Clark's method, 15. 
Clay, 13. 
Coal dust, 12. 
Coke, 12. 

Condensation in steam disinfectors, 27. 
Candy's fluid, 310. 

„ „ Red, 123. 

„ ,, Green, 123. 

,, powder, 126. 
Conine, 190. 
Copper, 113. 

,, acetate, 115. 

,, acetoarsenite, 133. 

„ chloride, 114. 

,, sulphate, 115. 
Corrosive sublimate, 135. 
Cowsheds, 243. 

' ' Creo " disinfecting powder, 75. 
Creolin, 166. 
Creosol, 176. 
Creosote, 161. 
Cresol, 160. 
Cresyl salicylate, 199. 
Crimson salt, 125. 
Culture and inoculation tests, 304. 
"Cupralum," 116, 132. 
Cyanogen, 142. 

Dairies, 243. 

Daudenant's patent. 111. 
Deodorant, Definition of, 2. 
Deodorisation, 7. 
Desiccation, 16. 
Destruction, 7. 
Diamine, 183. 
Diaptherin, 193. 
Dimethylamine, 183. 
Disinfectant, Definition of, 1. 
Disinfectants, Bacteriological examin> 
ation of, 300. 
„ Chemical, 307. 

Disinfecting, Primitive methods of, 2. 



Disinfection, Definition of, 1. 

„ by heat, 23. 

,, by steam, 29. 

„ Internal, 259. 

,, in the middle ages, 3. 

„ Personal, 252. 

Rules for, 295-298. 
Disinfectol, 156. 
IMsinfector, Budenberg's, 51. 

,, Equifex, 45. 

,, Goddard's, 36. 

„ house. Plan of, 52. 

,, Manlove's, 38. 

„ M'Lautlin's, 52. 

„ plant for U.S. marine, 54. 

„ Portable steam, 39. 

„ Reek's, 47. 

„ Schimmel's, 49. 

• „ Thursfield's, 43. 

„ Washington Lyon's, 34. 

Downes and Blunt's experiments, 8. 
Drains, 229. 

Dressings, Antiseptic, 256. 
Dust holes, 231. 
Duclaux's experiments, 16. 

Earth closets, 238. 
Eau de Javelle, 63. 

,, Labarraque, 63. 

„ St. Luc, 111. 
Eau Larnaudes, 112. 
Epidemics, Prevention of, 279. 
Equifex disinfectant sprayer, 235. 

,, water steriliser, 248. 
Essence of hops, 210. 
Essential oils, 213. 
Esset's fluid, 166. 
Ether, Nitrous, 39. 
Ethyl-amine, 184. 

,, bromide, 78. 

„ iodide, 78. 

,, nitrite, 89. 
Eucalyptol, 211. 
Eucalypto-resorcin, 212. 
Europhene, 78, 171- 
Exclusion of infected persons, 5. 

Fairs, 243. 

Ferric chloride, 121. 

,, sulphate, 120. 
Ferro-manganese, 122, 
Ferrous sulphate, 117. 
Filter, Berkefeld's, 15. 

„ Bischof's, 117. 

,, Pasteur-Chamberland, 14, 248. 

„ Stone, 15. 
Filtration, Sand, 14. 
Fluorides, 78. 

Fluorine, 78. 

Fluosilicates, 78. 

Food, Preservation of, 262. 

Formalin, 219, 272, 315. 

Formic aldehyde or formalin, 219, 272. 

Foreign systems, 291. 

Fowler's solution, 133. 

Furfurane, 187. 

Furfurol, 187. 

Furniture, 232. 

Furs, 244. 

Gannal's solution, 133. 

Gargles, 255. 

Gases, Influence of, on preservation, 104. 
Gases and liquids. Purification of, 10. 
Gases and vapours, 306. 
Gauze, Carboliued, 155. 
,, Iodoform, 77. 
Sublimate, 140. 
Germicidal value. Determination of, 303. 
Gibbsite, 131. 
Glacialin, 102. 
Glycerine, 226. 

Goddard's disinfecting chamber, 36. 
Gold compounds, 144. 

,, cyanide, 144. 
Goulard's extract, 134. 
Guaiacol, 175. 

„ carboxylate, 176. 
Gypsum, 13. 


Haddan'S patent, 88. 

Hager's test, 313. 

Hair, 244. 

Halogens, 57. 

Hartmann's process, 271. 

Heat as a disinfectant, 19. 

" Hermite " process, 67. 

Heydrich's salt, 102. 

Hille's method of disinfection, 128. 

Holden's process, 128. 

Hospitals, Rules for, 286. 

Hot air disinfection, 27. 

Houses, 231. 

Hydrazine, 183. 

Hydrocarbons, 148. 

Hydrogen peroxide, 84, 86, 309. 

Hydronaphthol, 179. 

Hydroxylamine, 183. 

Hygienic wall papers, 231. 

Hypochlorites, 63. 

Hypodermic injections, 257. 


IneinePatOP, Dr. Sergeant's, 53. 
Indole, 192. 
Infusorial earth, 13. 



Infectious diseases, 279. 
lodantipyrin, 189. 
lodates, 75. 
Iodine, 73. 

„ candles, 73. 
„ solution, 308. 
,, trichloride, 74. 
lodo-camphor, 211. 
Iodoform, 76. 

„ gauze, 77. 
lodol, 78, 188. 
lodophenol, 157. 
Iron, 116. 
,, carbide, 117. 
,, perchloride, 121. 
,, persulphate, 120. 
,, sulphate, 117. 
Izal, 169. 

Jaeobsen'S mixture, 86. 
Jeyes' automatic distributor, 241. 
Johnson's patent, 86, 247. 
Johnson and Saladin's patent, 96. 
Jones' process for preservation, 267. 


Keelin'S patent, 246. 
Key's screen, 247. 
Kieselguhr, 13. 
Kingzett's patent, 247. 
Kriiger's experiments, 129. 

Laetacidine, 202. 

Lano-creolin, 166. 
Lawes' fluid, 171. 
Lavallee's fluid, 176. 
Lead, 134. 

,, acetate, Basic, 134. 

,, nitrate, 134. 
Leather's process, 247. 
Leveson and Slater's process, 115. 
Light, action on bacteria, 8. 
Lime carbonate, 107. 

,, slaked, 107. 

,, sulphate, 107. 
Listerine, 102, 197, 209. 
Little's "soluble phenyle," 176. 
Loretin, 193. 
Lysol, 162. 


Magdeburgr preservative salt, 102. 
Magnetic carbide of iron, 117. 

Magnetic spongy iron, 1 17. 
Manganate of soda, 123. 
Manganates, 123. 
Manganese, 122. 

,, peroxide, 122. 

Manganous salts, 122. 
Mayor's powder, 155. 
M'Dougall's powder, 154. 
Medical ofiicer of health, Duties of< 277. 
Menthol, 209. 
Mercuric albuminate, 141. 

„ benzoate, 143. 

,, carbolate, 143. 

„ chloride, 135, 316. 

,, chloro-amide, 143. 

,, cyanide, 142. 

„ imidosuccinate, 143. 

,, iodide, 141. 

„ naphtholacetate, 143. 

,, naphtholate, 143. 

,, nitrate, 135. 

,, oxide, 135. 

,, peptonate, 143. 

,, salicylate, 143. 

„ sulphocarbolate, 143. 

,, tannate, 143. 

,, thymolate, 143. 
Mercurous nitrate, 135. 
Metallic salts, 145. 
Methane, 219. 
Methyl alcohol, 219. 

,, chloride, 219. 

,, guaiacol, 176. 

„ violet, 186. 
Methylamine, 183. 
Microcidine, 179. 
Milk, 272. 

,, Condensed, 273. 
Mortuaries, 280. 
Mouth M'ashes, 258. 
Mur's patent, 247. 
Myrtol, 212. 


Naphthalene, 148, 177. 

„ tablets, 148. 

Naphthol, 177, 315. 

,, salicylate, 179. 
Naphtholeum, 180. 

New Kiver Co. 's settling reservoirs, 16. 
Nicotine, 189, 192. 
Night-lights, Bromonaphthalene, 72. 

,, Sussex patent, 73, 77. 

Nitrate of lead, 134. 

„ of mercury, 135. 

,, of silver, 144. 

,, of zinc. 111. 
Nitric peroxide, 88. 
Nitrites, 88. 
Nitroantipyrin, 189. 
Nitrobenzene, 89, 181. 
Nitrocellulose, 182. 



Nitrogen trioxide, 88. 
Nitroglycerine, 182. 
Nitrophenol, 181. 
Nitro-toluene, 181. 
Nitrous ether, 89. 
Nunn's patent, 117. 

Odamine, 171. 

Oil, Carbolised, 155. 

,, Carraway, 210. 

,, Cinnamon, 210. 

„ Cloves, 209. 

,, Wintergreen, 199. 
Ointments, 259. 
Oxygen, 79. 
Oxyquinoline, 193. 
Ozone, 81. 
Ozonisers, 81. 

Pail system, 239. 

Paper, Antiseptic, 102, 140, 204, 255. 

Pasini's experiments, 9. 

Payen's patent, 88. 

Peat, 12. 

,, charcoal, 12. 
Perchloride of iron, 121. 

,, of mercury, 135. 

Periodates, 75. 

Permanganate of potash, 124, 310. 
Permanganates, 123. 
Persulphate of iron, 120. 
Petroleum, 148. 

jelly, 227. 
Phenol, 149, 310, 316, 234. 
Phenolith, 155. 
Phenosalyl, 200. 
Picot's fluid, 176. 
Piffard's patent, 266. 
Pigeon and fowl houses, 243. 
Pignol's fluid, 176. 
Pinol, 218. 
Piperidine, 189. 
Piperine, 190. 
Pixene, 163. 
Pixol, 163. 
Potassium arsenite, 133. 

,, bichromate, 132. 

„ borotartrate, 102. 

„ dinitro-ortho-cresol, 182. 

,, permanganate, 124. 

Port sanitary authorities, 280. 
Poudre de Come et Desneaux, 1.3. 
Preservatives, Influence of, on digestion, 

Privies, 239. 
Propylamine, 184. 
Public Health Act, 277. 
Pumice, 13. 

Purvis's patent, 93. 
Pyoctanin, 187. 
Pyridine, 190. 
Pyrocatechol, 173. 
Pyrogallol, 172. 
Pyrrol, 188. 

Quarantine, 298. 

Quicklime, 107. 
Quinine, 194. 
Quinoline, 192. 


Rademann's patent, 156. 

Radlauer's antisepsin, 112. 

Rags, 244. 

Raymond's disinfectant, 112. 

Resol, 174. 

Resopyrin, 189. 

Resorcinol, 171. 

Respirators, 259. 

Retinol, 174. 

Rotter ine, 113. 

Roylat disinfector, 126. 

Saeeharin, 197. 

Salicylated gauze, 204. 
Salicylate of zinc, 1 13. 
Salipyrin, 189, 199. 
Salbromanilide, 199. 
Salol, 199. 
Salophen, 199. 
Salts of the alkalies, 106. 
Salufer, 78. 
Salzer's process, 269. 
Sand filtration, 14. 
Sanitary acts, 277-284. 
,, carbon, 11. 
,, inspectors, 277. 
Sanitas, 86, 213. 
Saprol, 167. 
Sawdust, 13. 
Sewers, 229. 
Shale, 13. 

Shilton's iodine solution, 73. 
Sick rooms, 232. 
Silver compounds, 144. 

,, nitrate, 144. 
Sinks, 232. 
Skins, 244. 
Slag, 13. 

Slaughter houses, 243. 
Smith's carbolated fluid, 166. 
Soap, Antiseptic, 257. 

„ Carbolic, 156, 314, 
Society of medical officers of health. 

Suggestions by, 289. 



Soda, 108. 

Sodium arsenite, 133. 

,, carbonate, 108. 

,, chloro-borosum, 102. 

,, dithiosalicylate, 205. 

,, manganate, 123. 

„ parapheuol sulphonate, 158. 

,, peroxide, 86. 

,, sulphobenzoate, 197. 
Soluble tartar, 102. 
Soot, 12. 
Sozal, 158. 
Sozo-iodol, 78, 158. 

,, mercury, 158. 

Spencer's patent, 247. 
Spiegeleisen, 122. 
Stables, 243. 

St. Bede disinfectant, 139. 
Steam, Penetrating power of, 33. 
Stothert's process, 1 28. 
Streets, 241. 

Strock's antiseptic paper, 204. 
Styracol, 205. 
Styrone, 205. 
Sublimate gauze, 140. 
Sulphate of copper, 1 15. 
,, of iron, 117. 
,, of lime, 107. 
„ of zinc. 111. 
Sulphates, 98. 
Sulphide of arsenic, 134. 

,, of carbon, 98. 
Sulphite of aluminium, 132. 

,, of zinc, 113. 
Sulphites, 93. 

Sulphocarbolate of zinc, 1 13. 
Sulphur, 89. 

,, candles, Kingzett's, 93. 
,, ,.. Seabury's, 93. 

,, dioxide, 91. 
Sulphuretted hydrogen, 90. 
Sulphurous acid, 91. 

Tablets, Naphthalene, 148. 
Talc, 13. 
Tannin, 205. 
Tar, 147, 311. 

,, acids, 149. 

,, oils, Neutral, 148. 

,, Stockholm, 173. 
Taylor's Eoylat disinfector, 126. 
Terebene, 210. 
Terpin hydrate, 212. 
Terpinol, 212. 
Thallene, 193. 
Thiocamf, 94. 
Thiophene, 148, 187. 
Thymol, 208, 315. 
Timber, Preservation of, 250. 

Tin protochloride, 144. 
Tobacco smoke, 191. 
Toluene, 148.' 
Tooth powders, 258. 
Toxines, 6. 
Tribromophenol, 157. 
Tricresol, 164. 
Trinitrophenol, 181. 
Trimethylamine, 183. 
Turpentine, 207. 
Tuson's disinfectant, 112. 

,, patent, 93. 
Tweedie's powder, 155. 
Tyndall's experiments, 21. 
Tyrosine, 192. 

Urinals, 242. 

Vaccination, 262. 

Vegetable charcoal, 11. 

Vehicles, 244. 

Verdigris, 115. 

Victoria carbolic powder, 149.. 


Washing soda, 108. 

Water, 247. 

,, closets, 237. 
Wheat, 275. 

Wilson's disinfectant, 139. 
Wimbledon process, 129. 
Wintergreen oil, 199. 
Wood creosote, 174. 

„ paving, 242. 

,, tar, 173. 

„ work, 232. 
Wool, 244. 

,, Carbolised, 155. 

,, Medicated, 316. 

Zinc, 109. 

,, acetate, 113. 

„ chloride, 109. 

„ mercury cyanide, 142. 

,, nitrate. 111. 

„ oxide, 109. 

„ paraphenol sulphonate, 158. 

,, salicylate, 113. 

„ sulphate. 111. 

,, sulphite, 113. 

,, sulphocarbolate, 113, 158. 




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