REMARKS BY 
€c B„ WHITEa M. Ek3 Sanitary Director, 
Upon “ DISINFECTION,” 
As found on pages 81 and 82 of a pamphlet prepared by Dr. Joseph 
Jones and published by .the Board of Health—a pamphlet 
entitled, “Acts of the Legislature of Louisiana, establish- 
ing and regulating quarantine, etc.;” also, 
DISCUSSION OF ANALYSES OF DR. JONES, 
Appearing in the same article. 
By JOS. AIiBMECHT, Chemist. 
New Orleans, November 20, 1880. 
A valuable and much needed pamphlet has been lately prepared 
by Joseph Jones, M. D., of Louisiana, and officially published by 
order of the board—a pamphlet entitled, “Acts of the Legislature of 
Louisiana, etc.” Under the head of disinfectants occurs a table of 
analyses, entitled, “Results of the Chemical Analyses, by Joseph 
Jones, M. D., President of the Board of Health of the State of 
Louisiana, of zinc iron disinfectant, as offered in the market of New 
Orleans in 1879 and 1880.” 
This is accompanied by remarks to the discredit of the disinfec- 
tant used by this association. Mr. C. M. Soria, president of a chemi- 
cal manufacturing establishment, as contractor with the Sanitary 
Association, being necessarily included in the censure, the following 
note was addressed to Mr. Soria, who referred the same to Dr. Joseph 
Albrecht, consulting chemist to the works, at present and for 
some time past assayer at the U. S. Mint. 
New Orleans, November, 1880. 
0. M. Soria, Esq., President Stern’s Fertilizer and Chemical Manufac- 
turing Company, 11/. Union street: 
Dear Sir—I call your attention to “results,” etc., lately published 
by the Board of Health. As the manufacturing company of which you are president furnished nearly the whole of the zinc iron disin- 
fectant used by this association during the past and present year, I 
shall be pleased if you will furnish to the association such explana- 
tion as the statement of the results of the analyses seem to require. 
Very respectfully, your obedient servant, 
C. B. White, M. D., Sanitary Director. 
Dr. Albrecht’s discussion of the analyses has been forwarded to me 
by Mr. Soria, and appears later as a part of this paper. 
There is a serious omission in the analysis of the zinc iron, as the 
chloride of zinc is not mentioned, though forming, on an average, 
‘20 per cent of the metals of the solution, and the value of the 
chloride of zinc as a disinfectant, ignored. There is in the range of 
chemical agents of such cheapness as can be used freely, probably 
no one so deadly to low forms of life. 
Putrefaction is the work of bacteria of various forms. 
The destruction of the human body is to a great degree, if not 
wholly, so accomplished, and as all are aware this putrefaction proceeds 
in this climate with great speed yet such a body can be for many 
months protected from putrefaction if injected with chloride of zinc, 
which instantly kills all forms of low life, and as long as it remains 
prevents their reappearance. A body so prepared was preserved 
in an open coffin in the Charity Hospital for more than ten years, 
perfectly free from decay. Its action is similar on any masses of 
matter wTith a tendency to putrefaction. 
In all this discussion it must not be forgotten that deodorization 
and disinfection of vaults are only make-shifts of limited benefit, im- 
mediate removal of excreta being sound principle. 
The zinc iron disinfectant is a compound originated by Dr. A. W. 
Perry, after careful laboratory experiments and tests of its value on 
the matter of vaults. He discovered by actual trial that chloride of 
iron and zinc and copperas had no action on free sulphuretted hydro- 
gen, the most offensive and noxious gas that vaults emit, and acted 
upon it only when in alkaline combination. 
It follows, therefore, that the very presence of those proto salts 
mentioned in a vault, by giving an acid reaction to its contents, en- 
tirely prevents the destruction of the sulphuretted hydrogen. Dr. 
Perry found, however, that perchloride of iron acted on sulphuretted 
hydrogen whether free or combined, and this led to the adoption of the disinfectant composed of chloride of zinc and perchloride of iron, 
at the same time a deodorant and disinfectant. This chemical fact 
referred to above was not mentioned in many works on chemistry in 
vogue at that date, and many well informed chemists are not aware 
of it. 
The zinc iron disinfectant, made by A. K. Finlay, was prepared 
only as a sample, and was never in the market of New Orleans at 
all. 
With reference to the specimen of I. L. Lyons & Co., that estab- 
lishment offered a sample of the proper specific gravity, and guaran- 
teed to furnish a liquid in which the metals should be eighty per 
cent iron, twenty per cent zinc; the iron in the form of perchloride, 
and at a low figure. A considerable quantity was contracted for, and 
as soon as delivered a sample was analyzed with as little loss of time 
as practicable by Mr. Walton Clark, chemist to the gas works; and 
reported by him to be not at all up to the contract. 
Its use was immediately discontinued. It seems the representative 
of the house, during the absence of his regular manufacturing chem- 
ist, had employed one well recommended but an incompetent substi- 
tute, and that in his hands-the errors had been made. Mr. Walton 
Clark’s analysis being confirmed by that of Mr. John Johnson, the 
well known chemist of the Charity Hospital, the house of Lyons & 
Co., at once accepted pay for the amount used, at the actual value 
placed upon it by Mr. Clark, as the result of his analysis. The letter 
of Mr. Clark is preserved in the office, the bill with deduction and 
receipt is in the hands of the treasurer of the association. Four 
other specimens might be considered, but as the dates j^si 
are not given I can say nothing about them. 
Last summer, during the preparation of one of the lots of the disin- 
fectant at Stern’s chemical works, the supply of hydrochloric acid 
ran short, and the person practically manipulating its manufacture, 
having no particular chemical knowledge, used sulphuric acid in its 
stead. All new batches of disinfectant were always analyzed by Mr. 
Clark, and he found so very large an amount of sulphuric acid in this 
sample that it could not have been accidentally introduced. 
Mr. Soria being informed of the result of this analysis, was greatly 
surprised, and referred a sample to Dr. Albrecht. His results agree- 
ing with those of Mr. Clark, Mr Soria accepted the deduction deemed proper, and the receipted bills showing such reduction are in the 
treasurer’s hands. Mr Clark’s analysis and opinion are of record. 
A small quantity of zinc iron was made later on by Stern’s works at 
a much reduced price. In this form the sulphuric acid which gener- 
ated the muriatic acid remained in the disinfectant, but in the combi- 
nation of sulphate of sodium, a strong combination not likely to be 
broken up, and so render possible the evolution of ill-smelling sul- 
phides. On standing, however, basic chlorides of difficult solubility 
were thrown down. This form has therefore not since been used. 
The zinc iron used this year was from Stern’s Manufacturing Com- 
pany. When reported ready for use, Mr. Mumford went to the fac- 
tory, took the sample from the tanks, saw it drawn off into barrels, 
loaded into wagons and driven off. The objects of taking from the 
tanks was that the sample might represent the contents of all the 
barrels, and thus only a single analysis be required. 
Mr. Walton Clark found less than two per cent of sulphuric 
acid present and the disinfectant was accepted. 
For easy comparison the four remaining analyses of the zinc iron, 
by Dr Jones, have been reserved to this part of the paper. Mr. John- 
son, of the Charity Hospital, has furnished an analysis of a specimen 
procured by himself from the warehouse where it had been stored un- 
opened up to the date of the analysis. 
RESULTS OF CHEMICAL ANALYSES, ETC. 
Results of Chemical Analyses, by Joseph Jones, 31. D., President of 
Board of Health, State of Louisiana, of Zinc Iron Disinfectant, as 
offered in the market of New Orleans in -1870 and 1880: 
First District Sanitary office 
Free distribution A. S'. Ass’n 
Erich Brand 
Stern’s Fertilizing Company 
I. L. Lvons 
> 
w 
<1 
SAMPLES—WHENCE OBTAINED. 
M h-4 h-4 
tO CO CO 
CHU1 
CJ( © GO 
CO 
CO 
O 
Specific Gravity. 
b** fO to 
JO 
CO "trb'oo 
-<i co 
to to to 
to 
h-4 
© 
cn 
© 
Solid Matter to 1 
gallon, grains. 
>—4 H—4 
coop 
to 
If* © 
CD Q O 
12,800 
Oxide of Iron in 1 
gallon, grains. 
HMH 
o co_© 
OCOl 
tDCOO! 
© «<1 CO 
CO or 05 
CO OC GO 
'co 
GO 
CO 
© 
00 
Sulphuric Acid in 
1 gallon, grs. 
JO CO tf*- 
CTi h-* GC 
OJOifcO 
OCiO: 
o 
to 
OD 
'© 
Ol 
CO 
CO 
© 
Chlorine in 1 gal- 
lon, grains. 
Oxide Zinc in 1 
gallon, grains. Analysis of Stern's Fertilizing Company's zinc iron disinfectant of 18S0, 
by Jos. Albrecht, chemist, November 11, 1S80. 
Stern’s Fertilizing Co... 1 
WHENCE OBTAINED. 
H-i 
CO 
Specific Gravity, 
o 
to 
Solid Matter in 1 
p 
Gallon, grains. 
s 
l-A 
Oxide Iron in 1 
h-1 
00 
gallon, grains. 
•<1 
H-* 
1 
Sulphuric Acid in 
OO 
o 
1 gallon, grs. 
I o 
|m 
Chlorine in 1 gal- 
: to 
to 
Ion, grains. 
CO 
JO 
cs 
Oxide Zinc in 1 
1 p 
gallon, grains. 
Analysis of sample of zinc iron disin/eclant by J. Johnson, chemist at 
Charity Hospital, obtained from Neio Orleans Gas Works. 
N. 0. Gas Works 
WHENCE OBTAINED. 
1,333.8 
Specific Gravity. 
to 
Ol 
"to 
co 
«*■ 
cn 
Solid Matter in 1 
gallon, grains. 
t—i 
© 
CO 
co 
Fl 
OS 
Oxide Iron in 1 
gallon, grains, 
1,358.35 
Sulphuric Acid in 
1 gallon, grs. 
CO 
O 
CO 
as 
CO 
Chlorine in 1 gal- 
lon, grains. 
1,983.5 
Oxide Zinc in 1 
gallon, grains. 
The specimen of zinc iron of Dr Albrecht, was from an illy closed 
barrel found at the works. A comparison of the specimens makes it 
evident that the analyses of both Dr Albrecht and Mr Johnson show 
more solid matter in the gallon than any of the four of Dr. Jones’ list. 
That the oxide of iron is greater than of any, save in the Stern’s 
works specimen. Thatthe sulphuric acid is 1,139.6 and 1,135.8 grains 
in the analyses of Mr. Johnson and Dr. Albrecht, while that of the four 
of Dr. Jones amounts to about 9500 grains each. The chlorine appears 
in these four analyses of Dr. Jones as very nearly 3100 grains to the 
gallon, the analysis of Dr. Albrecht, however shows 16,100 grains to 
the gallon, and that of Mr. Johnson very nearly 14,000 to the gallon. 
This shoves that none of the analyses of this4year correspond at al lto 
those of Dr. Jones, and that when he asserts his analyses to have 
been of 1879 and 1880, he has merely made a twelve months’ pen 
slip. 
Dr. Albrecht has kindly presented an analysis of zinc iron in the 
modern form: Specific gravity 35 Baume; per chloride of iron, 27.31 
percent; persulphate o.f iron, 2.47 per cent; chloride ofzinc5.68per cent, 
solid matter 35.46 per cent. It will be seen therefore that of a gallon 
slightly over one-third of its weight consists of effective chemical agents held in solution. In estimating the relative value of copperas 
it is well enough to remember that of ten pounds purchased, about 
four pounds and a half is water—water of crystallization and value- 
less. 
Copperas is especially a deodorant. It is not better than zinc-iron, 
but as a disinfectant to destroy noxious germs it is incomparably in- 
ferior. What is wanted from a disinfectant is work. The chlorine of 
the zinc-iron is its expense and its value. When used properly, 
chlorine is steadily given off and in the form termed nascent, its most 
energetic shape. 
One object of these remarks is to inform the association as to the 
general policy which has governed the Sanitary Director’s Depart- 
ment in the selection and use of disinfectants. Another object is, 
that it was announced as part of the proceedings of the Board of 
Health at a late meeting that the pamphlet of Dr. Jones 
was to be republished in the Annual Report of the Board of Health. 
I therefore recommend that a resolution be passed by the associa- 
tion respectfully asking such modification of the article on disinfect- 
ants as shall on its republication do away with its seeming censure 
of the association, its officers and contractors. 
CHEMICAL DISCUSSION OF DR. JONES' ANALY- 
SES BY DR. ALBRECHT. 
New Orleans, November 12, 1880. 
Sir—Mr. C. M. Soria, President of “ Stern’s Fertilizer and Chemical 
Manufacturing Company,” referred to me for answer your communi- 
cation requesting him to explain the disparity of the composition of 
the zinc iron disinfectant furnished by his company to the Auxiliary 
Sanitary Association of this city, in 1879 and 1880, and the analyses 
of Dr. Joseph Jones, President of the Board of Health of the State 
of Louisiana, and published by him in a pamphlet entitled, “Acts of 
the Legislature of Louisiana, establising and regulating quarantine 
etc.” 
In answer, I beg leave to state, that Stern’s-Fertilizer Company 
furnished your honorable association no other zinc iron chloride than the one of the following composition, except a small quantity, in the 
beginning of 1879, whose composition was known to you: 
COMPOSITION OF ZINC IKON CHLORIDE. 
j 120 parts of zinc. 
(408 “ muriatic acid, 21 degrees Baumb. 
j 480 parts of irop. 
1 1878 “ muriatic acid, 21 degrees Baum6. 
f 936 parts of muriatic acid, 21 degrees Baume. 
} 636 “ nitric acid, 40 degrees Baum6. 
with a sufficient quantity of water to make a solution marking 35 
degrees Baume. 
A recent analysis of a sample taken out of a barrel in Stern’s 
factory proved to be composed as follows, in 100 grammes of solution: 
Perckioride of iron 27.31 
Persulphate “ 2.47 
Chloride of zinc 5.68 
Solid matter in 100 grammes 35.46 grammes, or 35.46 %. 
or, 
Sesquioxide of iron 14.31 “ 
Chlorine 20.94 “ 
Sulphuric acid 1.48 “ 
All iron was found to exist as perchloride or persulphate. 
It is very disagreeable to me to be compelled to defend my own 
reputation and that of Stern’s company, and to expose the seriously 
erroneous analyses of Dr. J. Jones. 
I am at loss to understand why Dr. Jones, who courts the public 
opinion as marching with the progress of the age, comes forward with 
the now obsolete quotation of troy grains and gallons, whilst now-a-days 
the metrical system is universally adopted in chemistry, as it conveys 
a far more easy comprehension of the results of chemical analyses. 
The parties here interested are not willing to aquiesee in this quasi 
accusation of ignorance or cupidity, but will prove unpardonable 
errors in his analyses. 
I have carefully prepared a systematic table showing all possible 
combinations with Dr. Jones’ weights of oxide of iron, chlorine and 
sulphuric acid, to prove how incorrect, nay, impossible, his analyses 
are. I was obliged' to assume all combinations possible as Dr. Jones 
did not state, if the chlorine and iron were combined as proto or per- 
chloride, which makes a great difference. If I had to answer your questions to a competent body of profes- 
sional chemists, this table alone would be deemed quite sufficient, 
because every one of them would be able to verify at once their cor- 
rectness; but, as this is intended for the public at large, i. e., for 
people not thoroughly conversant with chemical equivalents, the 
objection may possibly be raised, that these tables, after all, oppose 
only figures to figures, and, therefore, it is necessary to comment 
upon them and to show, by close reasoning, that Dr. Jones’ analyses 
cannot hold their ground. 
TABLE 
Showing the chemical composition of divers combinations of iron, zinc, 
sulphuric acid and chlorine, and the solid anhydrous matter resulting 
therefrom, calculated from figures given as the iesu.lt of analyses of 
Dr. Joseph Jones: 
Specific 
Gravity 
IRON-EQUAL TO 
Sulph’ric 
Acid. 
Chlorine. 
Solid 
Matter. 
Peroxide. !Protoxide|Met. Iron 
A. K. Finlay, by Dr. Jos. Jones. 
1.35| 16,640 I | | 323.02| 4,306.73| 19,392 
Chemical composition assuming the weight of sulphuric acid and 
chlorine as perchloride be as stated by Dr. Jones. 
322.8 
3,243.47 
290.6 
323.02 
6J3.62 
6,576.56 
2,270.83 
4,306.73 
3,566.27 
290.6 
2,270.83 
323.02 
4,306.73 
7,190.18 
Chemical composition assuming the chlorine as protochloride of iron. 
322.8 
4,864.69 
290.6 
323.02 
613 62 
7,712,61 
3,405.88 
4,306.73 
5,187.49 
290.6 
3,405.88 
323.02 
4,306.73 
8,326.23 
Chemical composition assuming 16,6t0 grains of oxide of iron as per- 
chloride. 
. 323.8 
16,317.2 
290.6 
11,426 
323.02 
21,673.81 
613.62 
33.099.81 
16,640 
290.6 
11,426 
323.02 
21,673.81 
33,713.43 
Chemical composition assuming 16,640 grains of oxide of iron as proto- 
chloride. 
322,8 
16/317.2': 
290.6 
14,426 
323.02 
14,449 
613.62 
25,875 
16,640 
290.6 
11,426 
323.02 
14,449 
26,488.62 Stern’s Fertilizing Company, by Dr. Jos. Jones. 
1.331 12,800 | | | 5,883.68| 8,053.36) 21,056 
Chemical compositi m assuming the sulphuric acid and the chlorine as 
stated by l)r. Jones; the chlorine combined as perchloride of iron. 
5,380.8s 
G, 0G5.lt 
4,824.77 
4,245.60 
5,383.68 
8,053.06 
10,208.45 
12,298.90 
11,446.02 
4,824.77 
4,245 GO 
5,383.68 
8 051.36 
22,507.41 
Chemical composition assuming tlio sulphuric acid and the chlorine 
correct and the chlorine combined as protochloride of iron. ' 
5,380.88 
9,096.72 
4,824.77 
5,383 68 
10,298.45 
14,422.20 
0,368.84 
8,053.36 
14,477,60 
4,824.37 
G,308 84 
5,383.68 
8,053.36 
24,630.65 
Chemical composition assuming the weight of the oxide of iron and 
sulphuric acid as stated by Dr. Jones and the necessary chlorine 
as perchloride of iron. 
5,380.88 
7,419.12 
4,824.77 
5,383.6s 
10,21(8.45 
15,916.23 
5.494.30 
10,421.98 
12,800 
4,824.77 
5,494.30 
5,383.68 
10,421.98 
25,124.73 
Let us admit that in the A. K. Finlay preparation, the weight of 
one or two substances to be correct, wo find, that the others are far 
out of Dr. Jones’ analysis—nay, straightway impossible—as in tho 
cases in which the oxido of iron i3 300 % and even nearly 500 % 
larger than there is sulphuric acid and chlorine to dissolve it 
As it is obvious that only 4-30G.73 grains of chlorine were intended, 
as printed, let us see what the result would be of its combination. 
Two cases are possible, the chlorino was combined either as proto 
chloride or as per-chloride of iron. 
In the first case, wre know that 430G.73 grains of chlorine would 
require 3405.88 grains of metalic iron, and produce 7712.G1 grains of 
proto-chloride of iron; and that 323.02 grains of sulphuric acid unit© 
with 290.6 grains of protoxide of iron to form G13.62 grains of 
sulphate of iron. 
But 3405.88 grains of metallic iron correspond with 48G4.69 grains 
of sesqui-oxide of iron, and 290.G grains of protoxide wdth 322.8 
grains of sesqui-oxide, therefore, wto have as result 5187.49 grains of 
sesqui-oxide of iron and 832G.23 grains of solid anhydrous mass, 
Dr. Jones says he found 1G,640 grains of oxide of iron, or more 
than three hundred per cent than the sulphuric acid and chlorine together can dissolve; he found also, 19,392 grains of solid matter, 
or 230 % more than could exist in a clear liquid. 
Assuming that the 4306.74 grains of chlorine were combined with 
iiron as per-chloride, it would require 2270.83 grains of metallic iron, 
to form 6576.56 grains of perchloride of iron; but 2270.83 grains of 
metallic iron correspond with 3243.47 grains of sesqui-oxide, add to 
this 322.6 grains ,of ferric oxide necessary for the sulphuric acid, and 
we have 3560.27 grains of oxide of iron and 6576.56 grains of per- 
choride, with 613.62 of copperas as above, making a total of 7190.18 
grains of solid matter. 
Dr. Jones found 16,610 grains of oxide of iron or 13,073.73 grains 
more (say 500 %) than the chlorine and sulphuric acid, stated by the 
Doctor, can make soluble or combine with. He also states, that he 
found 19,392 grains of solid anhydrous matter, whilst only 7190.18 
grains of solid matter can exist in a clear solution containing 323.Q2 
of sulphuric acid and 4306.73 grains of chlorine. 
Let Dr. Jones explain in what state or combination he found his 
excess of 13,073.73 grains of oxide of iron, or the 11,452.51 excess in 
the case of protochloride in his analysis. 
It is utterly impossible, that this enormous excess of ferric oxide 
can be made soluble with the quantity of sulphuric acid and chlorine, 
as stated by Dr. Jones. If this excess of oxide (nearly two pounds) 
was in its natural state and suspended in the solution, then the zinc 
iron chloride would not be a clear preparation, but a muddy slop. 
Assuming that the announced weight of oxide of iron be correct, 
in Dr. Jones’ analysis, we see, by looking over the table, that in the 
case of per-chloride it would require 21,673.81 grains of chlorine, and 
result in a total of 33,713.43 grains (anhydrous) dry matter. 
It would carry me too far to explain similar errors in Dr. Jones’ 
analyses of the Stern’s Fertilizer Company’s preparation, therefore, I 
refer you to my table. The errors are very grave, but not so exces- 
sive as in the analysis just discussed. 
As there is a great simillarity amongst the samples of Erich Brand, 
First District Sanitary Office, and Auxiliary Sanitary Association 
with that of I. L. Lyons, I presume that Dr. Jones had all samples 
from the same source, but certainly not from Stern’s Manufacturing 
Company. Therefore it seems to me very strange that Dr. Jones 
.should have obtained a sample from the Auxiliary Sanitary Associa- tion in 1880, which had nothing in common with that which they 
"bought from Stern’s Factory. It also seems that Dr. Jones never 
understood the true nature of this zinc iron disinfectant. 
Having shown and proven the fallacy of Dr. Jones’s analysis, it is 
worthy of mention that he seems to ignore, studiously, the pres- 
ence of chloride of zinc, which is one of the most energetic antisep- 
tics ive possess; it arrests putrefaction instantaneously whenever it 
comes in contact Avith decomposable matter; it absorbs sulphuretted 
hydrogen and sulphide of ammonium, under the same conditions 
(alkaline) as copperas, etc., etc. 
ORIGIN OF THE ZINC IRON CHLORIDE. 
Twelve or fifteen years ago Dr. A. W. Perry Avas connected with 
the Board Health existing at the time, of which Dr. C. B. White was 
president; he told me that he was experimenting with a disinfectant, 
which should not only act by immediate contact, but within a certain 
area through the air, and destroy Ioav organisms to a certainty. 
He found that chloride of zinc in combination Avith porchloride of 
iron, answered most satisfactorily all the requirements of a perfect 
disinfectant. 
When a solution of perchloride"' is exposed to contact of air, its 
oxygen takes possession of the iron of the perchlorido and forms 
oxide of iron, and an equivalent of chlorine in its free state is disengaged. 
Free chlorine is sure death to organisms. 
At that time, the high price of this preparation prevented its use, 
and carbolic acid and copperas Avere used as disinfectants. In latter 
years it was demonstrated that those tivo substances did not destroy 
the germs of Ioav organisms, unless they be employed in such con- 
centration, that their use becomes impracticable, besides many per- 
sons had objections to the strong odor of carbolic acid. Two years 
ago the use of carbolic acid and copperas did not visibly arrest the 
progress of yelloAv fever; it Avas then when the Sanitary Director of 
the Auxiliary Sanitary Association inquired of Mr. Soria and myself 
if Ave were Avilling to manufacture the zinc iron chloride. 
I composed several samples, one with two parts of iron and one of 
zinc, one Avith three parts of perchloride of iron and one of sulphate 
of zinc, and one Avith four parts of iron and one of zinc, the iron as per- 
chloride, the zinc as chloride, and as free from sulphuric acid as was 
commercially possible; this latter one was adopted by your honorable association, and a contract entered into with Mr. Soria for its prepar- 
ation under my superintendency, "but before the contract was con- 
cluded, your association advertised for sealed proposals. You had 
all the samples of competing firms analyzed and compared piices, 
and found Stern’s the best and the cheapest. 
It‘ the object is only to deodorize privies and not to destroy 
organisms, then copperas is the cheapest. 
On page 81 of the pamphlet Dr. Jones speaks of ‘ the disinfectant 
recommended by the Board of Health” as containing one pound of 
copperas to the gallon of water, but as one pound of copperas is 
nearly half water of crystalization, it represents nofi’quite nine ounces 
of dry anhydrous sulphate of iron, while the zinc iron disinfectant 
contains fifty-nine ounces of solid, active anhydrous matter. 
In the zinc iron disinfectant the iron must exist as a per-clilorido, 
since the pruio-chloride would not release its chlorine in contact with 
air. 
On tho property of the jper-chloride giving off its chlorine, the 
value of the disinfectant largely depends. 
Very respectfully, 
Joseph Albrecht. 
To Dr. C. B. White, Sanitary Director, 
New Orleans Auxiliary Sanitary Association.