The Petrol. proved by Hahnemann is made by agitating the liquid commercial Petroleum with Sulphuric Acid and then rectifying the portion which this acid does not act upon. It is "a light oily fluid, colourless or of a pale straw colour, and strong characteristic naphthalic smell. Dropped on white paper it evaporates completely, leaving no greasy stain." Under PARAFFIN I have described the relation between Petrol., Naph., and Paraff. Commercial "Petroleum" and commercial "Paraffin oil" are one and the same. The Petrol. of homoeopathy is this substance purified and rectified. But in the pathogenesis are included effects observed on those engaged in petroleum works, and those who use "Paraffin oil" in various trades; it would therefore be well to have also a preparation of the crude, non-rectified liquid. Petrolatum (Vaseline) consists of hydrocarbons of the Paraffin series, obtained from residues after distillation of lighter oils from crude petroleum; or deposited from crude petroleum on standing. The affections met with in petroleum extractors and refiners are—(1) Diseases of the skin and subcutaneous tissue; depressed nutrition, anaemia, dyspepsia, nerve troubles, irritability, insomnia, respiratory affections. In addition to these is a species of intoxication. A man, a patient of mine who suffered from inveterate eczema, and who had formerly been employed in a factory where much petroleum was used, noticed that his eczema was much better whilst working with petroleum. He told me that the vapour had the singular effect of making some of the workmen insane, causing: Desire to kill; hallucinations, they will see things not actually visible; for instance, "they will see the rails in a station when a train is on them." Boys (who are much affected) will jump at a straight wall and try to scramble up it. A rickety boy, aet. 2 1/2, who had an unconquerable desire to drink anything liquid within his reach I took one day e good draught of paraffin oil. An Ipecacuanha emetic and a Castor Oil purge got rid of a good deal of it, and a month after he was brought to me with these symptoms: Appetite had. Pale, dark rings round eyes. Every now and then seems to collapse; goes into a corner and will not play; after tea quite bright. Cold sweat in bed; complains of burning heat; then goes cold and clammy. I prescribed Phos. 2. In three weeks he was brought back much better. He had lost the pallor and dark rings round the eyes, and had ceased to mope; but he had come out, all over small boils which discharged, the discharge having the odour of paraffin. There was A slight recurrence of the old symptoms a fortnight later, and after that I did not see the boy again till a year later, when he was brought to me for diphtheritic paralysis. Two years after this he was brought to me again. He was now well grown and had no sign of rickets, but some of the old symptoms came back: Languid; inclined to be quiet; averse to play. At times clammy all over body. This time Petrol. 30 soon put him right. In the case of a woman who drank paraffin oil when intoxicated, there was epigastric pain so severe that she thought she would go out of her mind, > lying with knees drawn up; tenderness of ileo-caecal region and of epigastrium; swollen feeling of abdomen, without actual swelling; blood and albumen in urine; pain in back and slight return of menses, which had ceased a week before. These cases show the profound action of Petrol. on the organism. It is one of Hahnemann's leading antipsorics, and is especially closely related to Graph. It is suited to long-lasting, deep-seated, wasting diseases; lingering gastric and intestinal troubles with or without ulceration. In my experience no remedy corresponds to more cases of chlorosis in young girls, with or without ulceration of the stomach. Petrol. (says Kent) corresponds to low conditions in which there is inability to throw out eruptions on the skin; or conditions in which an eruption has disappeared without improvement in health: to reflexions of disease on mucous membranes setting up catarrh. Ozaena; intestinal catarrh. Soreness and cracks about muco-cutaneous orifices. Irritability of skin and irritability of mind are both found in Petrol., as in many other remedies: Excitable; angry at trifles. Anxiety with fear. Mental weakness and forgetfulness are also very characteristic, and are generally met with in connection with deep-seated disease. An illusion that there is another person, or another baby in bed, is very characteristic of the remedy, and has led to cures with Petrol. of cases of typhoid and puerperal fever. "Falling out of the hair" is a characteristic symptom of Petrol., and accounts for the popularity of Petroleum hair-restorers. [Petrol. "probably acts on the sebaceous rather than the sudoriferous secretions of the skin, and its local action is on parts where the sebum is abundant."—R. T. C.]. The use of these hair-restorers has caused many violent headaches. So has the use of "Coal Oil" (a tablespoonful to a bucketful of water) by washerwomen to improve the colour of linen. M. T. Bleim (quoted H. W., xxvi. 318) thus describes the result in one case: Severe occipital headache, loss of strength, emaciation, diarrhoea, dyspepsia with fulness on eating very little; accumulation of gas; very severe attacks of suffocation, > by eructations of gas. The headaches of Petrol. may be in any part, but they are most marked in occiput. Heaviness like lead; pressure, sticking; pulsating; < on shaking head or any jar. Pain travels from occiput to eyes, and is associated with temporary loss of sight and fainting. The vertigo and heaviness of Petrol. are often associated with nausea and bilious vomiting. This (nausea with or without vomiting) is one of the grand characteristics of the remedy. It is < by motion in a carriage or on the sea; hence Petrol. is one of the first remedies in train-sickness or sea-sickness. The other side of this nausea is another grand characteristic: Awful ravenous hunger, the "sinking" of the chief antipsorics. It is particularly noticed immediately after a stool, in diarrhoea, nervous affections, spinal disease, &c. (Kent). In pulmonary affections Petrol. has gained much repute of late in the form of an emulsion. A leading indication for it is "Oppression of the chest; < in cold air." Petrol. has a peculiar cough, not infrequently met with in young girls and boys, coming from deep down in the chest, and frequently waking the patient up at night. A student who had a deep, hollow-sounding, hacking cough, excited by laughing, waking him up in the middle of the night, I cured with Petrol. 30 after Arg. n. and Arg. met. had failed to do anything. The cough had persisted some time and caused his family no little anxiety. The discharges of Petrol. are thick, purulent, and yellowish green. For the cracked nostrils accompanying and following cold in the head I find the application of vaseline more often useful than other forms of unguent. The localities of Petrol. are very like those of Graph.: Scalp, behind ears, scrotum, genitals. The modality "< in winter" has given Nash the key to several cases of eczema, chapped hands, chilblains, and one case of chronic diarrhoea, as soon as he discovered that the patient had eczema of the hands in winter. Petrol. 200 was given. The skin is extremely sensitive; all clothing is painful; slight injuries suppurate. Allen's Appendix quotes an important case reported by O. Lassar in Virchow's Archiv. A man used for four days extensive inunctions with Petrol. to relieve himself from scabies. A week later his feet began to swell, and the dropsy, increasing rapidly, spread over abdomen and thorax. In a fortnight it disappeared, but eight days later returned and persisted till death, four months after the inunction. The urine was highly albuminous, and contained hyaline and granular cylinders; but the necropsy revealed no lesion of any organ to account for the dropsy. The, body was extremely oedematous; there was oedema of the lungs and dropsy of the cavities, and whilst in hospital the wrist pulse was small, empty, and of low tension; the blood corpuscles were few, but their relative proportions were normal. Temperature normal, and the skin showed localised areas of inflammation. Along the veins and lymphatics a small-celled growth existed, and in all the layers of the cutis there was a widely distributed nuclear proliferation. Peculiar symptoms are: Brain as if wrapped in a fog. As if everything in head were alive. As if head made of wood, or as if bruised. As if a cold breeze were blowing on head. As if head would burst. Veil before eyes. Sand in eyes. As if skin over bridge of nose drawn stiff and tight. As if something were tearing off from pit of stomach. As if a cold stone at heart. Splinter in heel. Upper and lower limbs as if stiff without joints. Jaw as if distended. There is great weakness; fainting; tremor; twitching of limbs; catalepsy; tonic spasms; left-sided paralysis. The notes of the skin affections are: Itching; burning; rawness; bleeding. Burning sensations are very marked; and as Petrol. is accountable for so many burning accidents it is fitting that it should make a very good application for burns in the form of vaseline, cosmoline, or Petrol. mixed with equal parts of olive oil. Petrol. is suited to: Persons with light hair and skin. Especially for lean, slender persons. The symptoms are < by touch; by contact of clothing; by scratching; by riding in carriage or ship. Pinching the parts > haemorrhoids. < From mental exertion. Headache < on shaking head; > by epistaxis; < from light and noise. After stool: hunger immediately. Ravenous hunger; frequently awakened by it at night; easily satisfied, with aversion to meat, fats, cooked or hot food; desire only for dainties, which are eaten with avidity. Eating > gastralgia. Gastralgia comes on whenever the stomach is empty. Empty, weak sensation in stomach. < After eating or drinking. After eating: giddiness; heat in face; cutting in abdomen; eructations; drowsiness; uneasiness. Cabbages, saurkraut = diarrhoea. Colic > by bending double. Exertion, motion, riding, sitting <. Lying down < cough, and distension of abdomen. Vertigo when head lies low. < Cold air. < Winter. < Open air. < Before and during thunderstorm. < Bathing. > Warmth and warm air. < Warmth of bed (itching). Cough is < at night and 2, 4, and 6 a.m. Smoking befogs him; = cough. < After coitus (nervous irritability). Cough < by laughing (cured). < During day (diarrhoea and dysentery). Throat affections go right to left. Headache back to front.