R E M ARKS 
ON SOME 
ALCLE FOUND IN THE WATER SUPPLIES OF 
J 
THE CITY OF BOSTON. 
By W. G. FARLOW. 
[Extracted from the Bulletin of the Bussey Institution, January,1877.] BULLETIN OF THE BUSSEY INSTITUTION. 
75 
7. - Remarks on some Algce found in the Water Supplies of 
the City of Boston. By AV. G. Farlow, Assistant Pro- 
fessor of Botany in Harvard University. 
It will be remembered that, in the months of October and Novem- 
ber, 1875, a peculiar taste was noticed in the drinking water of the 
City of Boston, which was generally described as resembling that of 
cucumbers. It is recorded that a similar taste was noticed in the 
autumn and winter of 1854; and, at that time, an investigation was 
made concerning its origin. The investigation, conducted by well- 
known chemists, did not result in assigning any definite cause for the 
taste; and in hinting that it might have arisen from Crustacea in which 
had been noticed a quantity of oil globules, the chemists were expressing 
an opinion which could only have weight when coming from a zoologist. 
When the taste reappeared in 1875, an examination of the water 
was made by Professor W. R. Nichols, Mr. Edward Burgess, and myself, 
to ascertain whether any substance known to chemistry, zoology, or 
botany, could have produced the peculiar cucumber taste. The results 
of our examinations are given in the " Report of the Cochituate Water 
Board," Boston, 1876; and it needs only be said, in this connection, that 
no assignable cause could be discovered, but that, as far as the botani- 
cal examination showed, the water was unusually pure; that from the 
Bradley Basin, where the cucumber taste was strong, being decidedly 
more free from vegetation, whether living or dead, than that from the 
Brookline Basin where the taste was not perceptible. Inasmuch as 
the subject of fresh-water algae is a terra incognita to water boards, upon 
whom not unfrequently devolves the duty of explaining to the public 
the cause of various unpleasant smells and tastes, it seems not inap- 
propriate to say a few words about what is known of the relation of 
those plants to smells and tastes, even if it should amount to a confes- 
sion of a very considerable ignorance. 
It has long been believed, by that part of the public which is inter- 
ested in botany, that the algae known as nostocs have a disagreeable 
odor, and, in many cases where unpleasant odors have arisen in 
bodies of water which serve as water supplies, it has been considered 
a sufficient explanation to say that the odor is produced by some 
nostoc-like plant, without, however, going so far as actually to find 76 
BULLETIN OF THE BUSSEY INSTITUTION. 
the plant which is supposed to be a nostoc. Undoubtedly, the most 
disagreeable odor ever found in fresh water may be produced by 
nostocs, using that word to designate the order Nostochinece; but by 
no means all of the disagreeable odors and tastes arise from that source. 
To return to the cucumber taste, there is not the slightest proof that 
it is caused by any algas, either living or decaying. The water from 
the Bradley Basin showed no nostocs whatever, and no algae of any 
kind not also found in waters which did not have the cucumber taste. 
During the past summer, we have made experiments to ascertain the 
taste produced by different species of algae. For this purpose different 
species of Desmidiece, Confervas, and OsciUarice, were allowed to 
stand several weeks in glass jars filled with pure water; but, in no in- 
stance, was any thing like a cucumber taste produced, nor, in fact, was 
any describable taste perceived. 
As far as smells are concerned, our knowledge is more complete. 
It is known that, when living, different species of nostoc may produce 
two different kinds of disagreeable odors: first, an indescribably 
suffocating odor, as in the case of several Lyngbyce and Oscillaria ; 
and secondly, a sulphurous odor, as is given off by species of Beggicdoa. 
A still more disagreeable odor is given off by species of nostoc in 
decay, an odor resembling that of a pig-pen or very strong horse- 
dung. Most persons who have in midsummer walked through the 
bogs so commou in New England must have recognized the stifling 
odor given off by the bluish-green masses growing on the mud or in 
shallow water. These are usually species of Oscillaria, composed of 
filaments made up of small cells in rows, the filaments capable of 
moving on one another, so that, when placed on any flat surface, they 
push out from one another, and spread over a larger area, or, if placed 
on the bottom of a tumbler, they crawl up the sides. The chemical 
nature of the stifling odor is not known. This peculiar stifling 
quality is not peculiar to nostocs, or even to fresh-water plants. It is 
marked in several marine plants, as Polysiphonia fastigiata, which 
forms blackish tufts on the larger rock-weed. 
The algas which exhale sulphurous odors belong to the genus Beg- 
giatoa, which resembles Oscillaria in consisting of filaments endowed 
with motion, but which differs in color, being whitish, the cells being 
full of opaque granules. They look to the naked eye like white 
films covering decaying algje and other plants. They are found on BULLETIN OF THE BUSSEY INSTITUTION. 
77 
the sea-shore as well as in fresh water, but are particularly common in 
hot springs. Cohn has shown that the peculiar exhalations of hot 
sulphur springs are owing to the growth of species of Beggiatoa* 
which depend for their existence upon, at least, two conditions ; the 
presence of a large amount of sulphur in the water, and the absence 
of iron. Cohn confirms the observations of Cramer, that the dark 
granules in species of Beggiatoa consist of sulphur. When Beggiatoa 
filaments are heated, the granules fuse into large yellowish drops and 
a sulphurous odor is developed. If the filaments are treated with 
sulphide of carbon, the granules are dissolved, and then the cell parti- 
tions become for the first time visible. 
The odor produced by decaying algae of the order Nostochinece was 
brought most strikingly to our notice during the last summer. In the 
month of August, we were asked to examine the waters of Horn 
Pond, situated in the town of Woburn, nine or ten miles from Boston, 
and the head-waters of what is known as the Mystic basin, which 
supplies Charlestown and East Boston. It was stated that a disgust- 
ing odor, said to resemble that of a pig-pen, had appeared in several 
portions of the pond. On inquiry, we found that there had been a 
quantity of a plant called eel-grass washed ashore, and upon it was a 
slimy mass from which the odor seemed to proceed. The slimy masses 
were not limited to any particular part of the* pond, and, although very 
abundant at the upper end, they were also common at the outlet. At 
the time of our visit they were said to be by no means as numerous 
as two or three days before. The eel-grass, so called, to our great 
surprise, proved to be not what is generally known by that name 
( Vallisncria spiralis) or even any of the common pond-weeds (Pota- 
mogeton, Myriophyllum, Ceratophyllum), but a new species of Plec- 
tonemaft of the order Nostocldneoe, which we had never seen growing 
* For an account of the physiological and chemical relations of the genus 
Beggiatoa, vid. " Beitrage zur Biologie der Pflanzen," by Cohn, Vol. 1, Part III., 
pp. 172-180, where references are given to the earlier writings of Cohn and others 
on this subject. 
t Plectonema Wollei, n. sp. Trichomatibus atro-viridibus in massas pluri- 
pedales intricate coalitis ; ramis parcibus obtuse exeuntibus plerumque singulis 
rarissime geminatis. Trichom. diam. .00388 m. m.; c. vagina .00405 ; articulis 
circa .000485 m. m. latitudine. Species magnitudine et ramis parcibus facile 
distincta. Species generis nobilissima a cel. Wolle prope Bethlehem in Pennsyl- 
vania primum inventa est. Ad Horn Pond prope Boston detexi. Species a cel. 
Rabenhorst in Algis Europseis, no. 2440, sub nomine Lyngbya Wollei, Farlow, 
distributa est. 78 
BULLETIN OF THE BUSSEY INSTITUTION. 
before, and which was first observed by the Rev. Francis Wolle in the 
waters near Bethlehem, Pa. It grew in great abundance at the head 
of the pond where the water was shallow, attached to other plants 
and sticks, and spread over the surface in areas of several square feet, 
forming blackish green patches like the plant called mermaid's hair 
(JL/yngbya majuscula) on the sea coast, only very much more luxuriant. 
Where the Plectonema was free from the slimy substance, it emitted 
the suffocating smell of many of the Oscillarice, but was free from the 
pig-pen odor. 
In various places along the edge of the pond, and in some places 
where the Plectonema came to the surface, were masses of slime, at 
first of a pale bluish-green, afterwards of a brownish color. The 
odor was most disgusting, and resembled rotting horse-dung to such 
an extent that it was difficult to believe that it came from a vegetable 
substance. A microscopic examination showed that the slime was 
composed of an amorphous mucus, in which were the threads composed 
of the heterocysts and hormogonim peculiar to the Nostocs proper, but, 
unfortunately, in a too advanced stage of decomposition to be specifi- 
cally determined. An examination of the water of the pond showed 
it to be full of little rods, which shone in the sunlight. These rods 
had the same microscopic structure as the filaments of the slimy 
masses which were evidently aggregations of decaying filaments, which, 
in a normal condition, float freely in the water. At the time of our 
visit, however, even the filaments which were still floating, were so far 
disintegrated that, after an unavoidable journey of several hours in 
the cars, they were not in a condition to be specifically determined. 
We are entitled to assume that the alga was a species of Anabcena or 
some nearly related genus, perhaps Nodular la litorea, Thuret, the de- 
composition of large quantities of which produced an intensely disa- 
greeable odor near Deauville, Normandy, in August, 1874, as we 
learn from Dr. Bornet. 
Early in October, we again visited Horn Pond, with the purpose of 
obtaining some of the Anabcena, if possible. It had, however, com- 
pletely disappeared. Furthermore, the Plectonema, which in August 
was attached, was washed ashore in immense quantities, leaving the 
surface of the pond clear. A quantity of the Plectonema was kept for 
some time until it began to decay, when that too began to give off an 
odor of pig-pen, which could hardly have arisen from any remains of BULLETIN OF THE BUSSEY INSTITUTION. 
79 
the Anabcena, as a microscopic examination showed no traces of it. 
It would seem then that the peculiar odor, which was so marked in the 
case of Horn Pond, may arise from decay of more than one species 
of the Nostochinece, and the probability is that a large number of spe- 
cies may produce it. The important point is, that it is during their 
decay that the odor is found; not while they are growing. The ques- 
tion arises as to what killed the algae so suddenly. Those living near 
the pond are quite ready to believe that it was the refuse from the 
tanneries, but there is no proof whatever that that was of a different 
character from what it had been previously, and the question is still 
open, why at that particular time the algae were killed. It will be 
remembered that, during the month of August, 1876, the heat was 
excessive, and the temperature of the surface water was raised con- 
siderably. We cannot doubt that the broiling rays of the sun had 
a destructive effect on the Anabcena, especially that which was 
caught in the meshes of the Plectonema, and, by the falling of the 
water consequent upon the drought, exposed on the surface. 
From the preceding account of the condition of Horn Pond, we are 
warranted in drawing certain conclusions which may on some occasion 
prove useful to water boards. If a sudden odor of pig-pen arises, it is 
in all probability owing to the decay of large quantities of some algae 
of the nostoc family, and most probably one of the finer species 
diffused through the water. As the decay is generally, if not always, 
brought about by causes beyond human control, it is useless to try to 
stop it when it has once begun. On the other hand, there is no occa- 
sion for great alarm; for, when they have once begun to decay, algae 
like Anabcena disappear in a few days. In the case of Horn Pond, 
we understand that the odor lasted barely a week from the time when 
it was first perceptible. As to the possibility of the putrescent masses 
being carried any great distance, in the case of Horn Pond it was 
found that they advanced as far as Winchester, not more than two 
miles in a direct course, but were not found farther on. They never 
made their appearance in Charlestown or East Boston. Knowing 
that floating algae are caught in the meshes of Plectonema and other 
similar filamentous algae, and thus, during the sinking of the water, 
which usually occurs in July and August, exposed on the surface to 
the direct heat of the sun's rays, which cause them to decompose, it is 
evident that it is a useful precaution to remove, as far as possible, the 80 
BULLETIN OF THE BUSSEY' INSTITUTION. 
long filamentous algae and fine-leaved phanerogams. No plant of our 
waters is of such large size, or of such fine meshes, as the Plectonema 
Wollei, which, although as yet recorded in only two localities, will 
probably prove common enough. It is a summer plant, and does not 
attain considerable dimensions' before July. It starts on the stems, 
leaves, and old sticks on the bottom, and forms coils several feet in 
length. On reaching the surface, it expands over considerable areas. 
In the latter part of September, it breaks away from its attachments, 
drifts ashore, and disappears to return the next summer. 
In conclusion, a word about another plant common at Horn Pond, 
and which has been sent to us from several localities, with inquiry as 
to its nature. It forms a bluish or yellowish green scum on the water, 
often spread over a considerable area. Were it not that it forms such 
a thin layer, it could be collected in large quantities. Kept in bottles, 
it multiplies and forms irregular masses of a pea-green color and mealy 
consistency. At first solid, the superficial cells imbedded in a gela- 
tinous mass increase rapidly, and it becomes hollow. Then certain 
portions project like buds, and finally separate from the mother plant, 
which seems to be perforated. This plant, Clathrocystis ceruginosa* 
was described by Henfrey, and is now classed by Cohn amongst the 
Bacteria, and placed near Clathrocystis roseo-persicina, a plant which 
forms purplish red films on decaying alga?, and on the ground along 
our coast, and which in Europe is also found in fresh water, but 
it has not yet been found in the interior of our own country. We 
mention it from its frequent occurrence, and because it has been sup- 
posed to injure the water in some places. There is no account of any 
injury having been done to man; but in Germany, where it is known 
as the Wasserbluthe, it has been destructive to fishes. Cohn f suggests 
that the slimy substance of which it consists, forms a coating over the 
fish, and shuts off the supply of air necessary to support life. Professor 
Hagen, of Cambridge, suggests, as a remedy, the introduction of snails 
into water where it occurs, as they are extremely voracious, and 
eat large quantities of fresh-water algae. 
* " Trans, of the Microscopical Society of London," 1856. 
t " Aus neuester, wie aus alterer Zeit besitzen wir Nachrichten, dass die 
Fische in einem Teiche, welcher mitder Wasserbliithe dieser alge sich bedeckt, 
massenhaft absterben ; vielleicht wird durcli die dicke Schleimhaut die Auf- 
nahme des fiir das Athmen der Fische unentbehrlichen Sauerstoffs aus der Luft 
gehemmt." Beitrage zur Biologie, Vol. 1, Part III., p. 155.