190. When the film blisters, the plate should bo laid, varnished side downwards, upon a vessel filled with equal parts of ether and alcohol, when the film would he softened and lie down again flat. The varnish might also be removed by dissolving it at once with alcohol and potash, but that often displaced and injured the collodion film. - Herr Criefelds.

Rents in the varnish of negatives may be removed thus: I had been frequently troubled by worm-like rents in valuable plates, and tried a variety of ways of removing them. With powder i got no good results, nor with rubbing in black with oil of turpentine; indeed, that sometimes loosened the film. I now always use a little dust from a corner of the studio, rubbed in with a piece of wadding. Of course, when the rents are wide they must be filled in by retouching. Herr Brischke used powder scraped off lead-pencils. - Herr Criefelds.

Some are inclined to attribute the cause to dampness, others to dirty plates; but my experience has, I think, exposed the real fact that, air dry or damp, plates dirty or clean, an abrupt change of temperature is the guilty worker of the damage. I remember on one 0 casion (which by the way, prompted my study of the subject) taking a quantity of negatives safe and sound from the storeroom over night, preparatory to printing from them on the following morning; hut, when that morning dawned, on going to the box I found that mischief had preceded me, and had worked ruin in shapes labyrinthine and fantastic. The lesson was imparted in brief; but I quickly learned the necessity of transferring negatives at once from the storeroom to frames when their removal happened in dull winter. The better plan, however, of avoiding the danger is, doubtless, that which would make such accidents less liable - better still, impossible.

191. And now, having piloted your negatives safely across this wide sea of troubles, do not forget that there are one or two things that may give you personal trouble, and oven cause your death if care is not exercised. The first of these is from the use of cyanide of potassium. It can be entirely and utterly dispensed with, and it should be. But there is a perver-suv about the photographer, also peculiar to human nature, which causes him to employ means to secure his results in his own way, despite the many drawbacks pointed out by others. Hence a note further on on this.

Happily, an efficacious remedy lies within reach of every sufferer. They have only to take heed that they be not again ensnared by the fallacious promises of brilliant, crystal-like varnish; for therein lies the secret of the primary cause. Hard and non-elastic, the varnish flim refuses to budge when the glass expands under pressure of heat, or contracts when exposed to extreme or, as it sometimes happens, even moderate cold, and the fruits of that stubbornness consist either in the varnish coat separating into transparent, hair-like lines or in rising in marbled ridges - in either case dragging along with it the collodion film, and thus ruining the most valuable negative beyond the chance of redemption. Varnishes that yield a hard, brilliant surface at all times are indicative of danger, and, as such, suggest the propriety of modification - either by adding alcohol to reduce the non-yielding body to subjection, or by an addition of an elastic gum, such as gum frankincense, to induce pliability. - W. T. Bovey.

191. Whenever an accident cccurs from imprudent use of cyanide, such as sometimes happens from an operator placing his chapped or otherwise broken hands into cyanide solution, the first thing to be done in case of giddiness or faintness, is to wash the wound in a saturated solution of chlorine at an ordinary temperature. The patient should also immediately swallow two or three grammes of the same solution in a glass of water, without waiting to put sugar in it. He should be at once put to bed, or on the nearest couch, and covered up with warm blankets, hot-water bottles being placed at his feet and along the whole length of his body. The windows are opened everywhere to secure a good circulation of outdoor air, for plenty of pure air is as necessary as warmth in such cases. Tea or coffee is now prepared, and the patient receives a cup with ten drops of laudanum and one or two spoonfuls of any alcoholic liquor, such as rum or brandy. This dose is repeated three or four times, at intervals of from fifteen to thirty minutes.

In cases where the symptoms are very severe, or where the poison has been taken internally, in addition to the above precautions, the dose of chlorine should be five instead of two or three grammes.

The patient should be allowed to inhale frequently from a vessel containing chlorine water. Every five minutes a teaspoonful of the following potion should be administered:

Chlorine Water,.........................................................

5 grammes

Chlorohydrate of Ammonia,......................................

2 ,,

grammessugar Water,......................................

250 ,,

As soon as the patient is better, the laudanum is left out of the tea, and the potion given only once in fifteen minutes.

192. The other affliction general to the photographer is the staining of his hands. As cleanliness is advocated all through his manipulations, when the work of the day is ended he also wants to appear clean. This is laudable enough, but do not use cyanide of potassium for vanity's sake. It is perhaps, the easiest and quickest means of cleansing the hands, hot it is also the most dangerous, and should never be resorted to.

193. Still another evil - and perhaps the most insidious of them all the inhalation of poisonous fumes. Photography is not necessarily an unhealthy vocation. There are many veterans in our art who are - till abundance, he will breathe them in such attenuation that they will do no harm. - Dr. Norman Bridge.

It is well to have the above potion and the solution of chlorine always on hand, and labelled with directions for use. A case of such poisoning may not occur in a gallery once in a lifetime; but still, if it does occur,a valuable life may be saved by the prompt use of the above remedies, and on the delay of a minute vital issues may depend. - J. L. Gihon.