Department of History
University of California, Irvine
  Instructor:   Dr. Barbara J. Becker


Week 7.  Growth

excerpts from
Description of some Experiments made with the Voltaic Battery
... for the purpose of producing Crystals;
in the process of which
Experiments certain Insects constantly appeared.  (1839)
from The American Journal of Science & Arts, vol. 35:  125-137
by Andrew Crosse (1784-1855)

Broomfield, Dec. 27, 1837.           

My dear Sir -- ....My object in subjecting this fluid to a long-continued electric action, through the intervention of the porous stone, was to form, if possible, crystals of silica at one of the poles of the battery, but I failed in accomplishing this by those means.  On the fourteenth day [14 in the illustration below] from the commencement of the experiment, I observed, through a lens, a few small white excrescences or nipples projecting from about the middle of the electrified stone, and nearly under the dropping of the fluid above.  On the eighteenth day [18], these projections enlarged, and seven or eight filaments, each of them longer than the excrescence from which it grew, made their appearance on each of the nipples. 

On the twenty second day [22], these appearances were more elevated and distinct, and on the twenty sixth day [26], each figure assumed the form of a perfect insect, standing erect on a few bristles which formed its tail.  Till this period I had no notion that these appearances were any other than an incipient mineral formation; but it was not until the twenty eighth day, when I plainly perceived these little creatures move their legs, that I felt any surprise, and I must own that when this took place, I was not a little astonished. 

I endeavored to detach, with the point of a needle, one or two of them from its position on the stone, but they immediately died, and I was obliged to wait patiently for a few days longer, when they separated themselves from the stone, and moved about at pleasure, although they had been for some time after their birth apparently averse to motion.  In the course of a few weeks, about a hundred of them made their appearance on the stone.  I observed that at first each of them fixed itself for a considerable time in one spot, appearing, as far as I could judge, to feed by suction; but when a ray of light from the sun was directed upon it, it seemed disturbed, and removed itself to the shaded part of the stone.  Out of about a hundred insects, not above five or six were born on the south side of the stone.  I examined them with the microscope, and observed that the smaller ones appeared to have only six legs, but the larger ones eight.  It would be superfluous to attempt a description of these little mites, when so excellent a one has been transmitted from Paris.  It seems that they are of the genus Acarus, but of a species not hitherto observed.  I have had three separate formations of similar insects at different times, from fresh portions of the same fluid, with the same apparatus.  As I considered the result of my experiment rather extraordinary, I made some of my friends acquainted with it, amongst whom were some highly scientific gentlemen, and they plainly perceived the insect in various states.  I likewise transmitted some of them to one of our most distinguished physiologists in London, and the opinion of this gentleman, as well as of other eminent persons to whom he showed them, coincided with that of the gentleman of the Academie des Sciences, as to their genus and species.  I have never ventured an opinion as to the cause of their birth, and for a very simple reason -- I was unable to form one.  The most simple solution of the problem which occurred to me, was that they arose from ova deposited by insects floating in the atmosphere, and that they might possibly be hatched by the electric action.  Still, I could not imagine that an ovum could shoot out filaments, and that those filaments would become bristles; and moreover, I could not detect, on the closest examination, any remains of a shell.  Again, we have no right to assume that electric action is necessary to vitality, until such fact shall have been most distinctly proved.  I next imagined, as others have done, that they might have originated from the water, and consequently made a close examination of several hundred vessels, filled with the same water as that which held in solution the silicate of potassa, in the same room, which vessels constituted the cells of a large Voltaic battery, used without acid.  In none of these vessels could I perceive the trace of an insect of that description.  I likewise closely examined the crevices and most dusty parts of the room with no better success.  In the course of some months, indeed, these insects so increased, that when they were strong enough to leave their moistened birthplace, they issued out in different directions, I suppose in quest of food; but they generally huddled together under a card or piece of paper in their neighborhood, as if to avoid light and disturbance. 

In the course of my experiments upon other matters, I filled a glass basin with a concentrated solution of silicate of potassa without acid, in the middle of which I placed a piece of brick, used in this neighborhood for domestic purposes, and consisting mostly of silica.  Two wires of platina connected either end of the brick with the poles of a Voltaic battery of sixty three pairs of plates, each about two inches square....  In the course of time, I observed similar insects, in their incipient state, forming around the edge of the fluid within the jar, which when perfect, crawled about the inner surface of the paper with great activity.... 

...[A]nd in due time a host of insects made their appearance.  It was curious to observe the crystalized nitrate and sulphate of copper, which formed by slow evaporation at the edge of the respective solutions, dotted here and there with these hairy excressences.  At the foot of each of the cylinders, I had placed a paper ticket upon the table, and on lifting them up, I found a little colony of insects under each, but no appearance whatever of their having been born under their respective papers, or on any part of the table.... 

After some months' electrical action, gelatinous silica enveloped both wires, but in much greater quantity at the positive pole; and in about eight months from the commencement of the experiment, on examining these two wires very minutely, by means of a lens, having removed them from the solution for that purpose, I plainly perceived one of these incipient insects upon the gelatinous silica on the silver wire, and about half an inch below the surface of the fluid, when replaced in its original position. 

"Figure of one of the insects formed under the influence of Voltaic electricity --
April -- 1837...."
In the course of time, more insects made their appearance, till, at last, I counted at once three on the negative and twelve on the positive wire.  Some of them were formed on the naked part of the wires, that is, on that part which was partially bare of gelatinous silica:  but they were mostly imbedded more or less in the silica, with eight or ten filaments projecting from each beyond the silica.  It was perfectly impossible to mistake them, after having made one's self master of their different appearances; and an occasional motion in the filaments of those that had been the longest formed was very perceptible, and observed by many of my visitors, without my having previously noticed the fact to them....  Whether they were in an imperfect state (except just at the commencement of their formation), or in a perfect one, they all had the distinguishing characteristic of bristles projecting from their bodies, which occasioned the French savans to remark that they resembled a microscopic porcupine.  I must not omit to state, that the room in which these three batteries were acting was kept almost constantly darkened. 

It was not my intention to make known these observations until I myself should be better informed about the matter.  Chance led to the publication of an erroneous account of them, which I was under the necessity of explaining.  It is so difficult to arrive at the truth, that mankind would do better to lend their assistance to explore what may be worth investigating, than to endeavor to crush in its bud that which might otherwise expand into a flower.  In giving this account, I have merely stated those circumstances regarding the appearance of insects, which I have noticed during my investigations into the formation of mineral matters; I have never studied physiology, and am not aware under what circumstances the birth of this class of insects is usually developed.... 

I am not aware that I have any thing more to add, except the few remarks I shall conclude with.

1st.  I have not observed a formation of the insect, except on a moist and electrified surface, or under an electrified fluid.  By this I do not mean to assert that electricity has any thing to do with their birth, as I have not made a sufficient number of experiments to prove or disprove it.... 

2dly.  These insects do not appear to have originated from others similar to themselves....

3dly.  I believe they live for many weeks:  occasionally I have found them dead in groups, apparently from want of food. 

4thly.  It has been frequently suggested to me to repeat these experiments without using the electric agency; but this would be by no means satisfactory, let the event be what it would.  It is well known that saline matters are easily crystallized without subjecting them to the electric action; but it by no means follows that, because artificial electricity is not applied, such crystals are formed without the electric influence.  I have made so many experiments on electrical crystallization, that I am firmly convinced in my own mind, that electric attraction is the cause of the formation of every crystal, whether artificial electricity be applied or not.  I am, however, well aware of the difficulty of getting at the truth in these matters, and of separating cause from effect....

Yours, very sincerely,


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