FERRUM. 79 



plasma. Tt combines with the haemoglobin, and as such alone 

 exists in the blood. In normal blood a " course " of iron in- 

 creases the richness of the blood ; whilst in anaemia the rapidity 

 of the growth of corpuscles and of the rise in value of the 

 haemoglobin, as estimated day by day with the haemoglobin- 

 ometer and haemacytometer, is remarkable. Iron is accordingly 

 used as a hsematinic in an endless variety of conditions in which 

 haemoglobin is deficient, such as simple anaemia, scrofula, 

 amenorrhcea, cardiac disease, syphilis, malarial cachexia, and con- 

 valescence from acute disease. The cautions already given re- 

 specting digestion must be faithfully respected, to secure its 

 haematinic action over a length of time. Iron is an important 

 constituent of many well-known mineral waters, the most 

 important being those of Spa, Tarasp, Kissingen, Kreut- 

 znach, Pyrmont, and St. Moritz on the Continent ; Harrogate, 

 Moffat, and Strathpeffer in this country ; and the Rawley 

 Springs, Sweet Chalybeate, and Bedford, in the United States. 



3. SPECIFIC ACTION AND USES. 



Iron has no specific action on the organs apart from the 

 blood ; and the tonic effect which it produces so satisfac- 

 torily, appears to be entirely referable to its action on the blood. 

 Abundance of oxygen is essential for every bodily and mental 

 function ; and the feeling of " tone," vigour, and mental fitness 

 varies with the degree of oxygenation of the blood, i.e. with the 

 quality of the blood as regards haemoglobin. Nervous, mus- 

 cular, and cardiac debility are thus removed by iron, and even 

 digestion is restored by this gastric irritant, if it can be success- 

 fully introduced into the blood. The temperature is said to be 

 slightly raised by iron, showing increased oxydation. Iron has 

 also a specific effect in erysipelas, diphtheria, and other adynamie 

 diseases, which cannot be perfectly explained. Fever is gene- 

 rally held to contraindicate the use of iron ; and the same may 

 be said of phthisis, except as mild forms in chronic cases. 



4. REMOTE LOCAL ACTION AND USES. 



Iron is excreted by almost every possible channel. As it is 

 absorbed, so a portion of it is excreted, along the whole Irn.irth 

 of the intestine, and colours the faeces black (sulphide). Only 

 a small amount escapes in the urine, saliva, sweat, the milk in 

 women, the pancreatic juice, and by the various mucous sur- 

 faces. Whilst passing out of the system, iron produces a 

 second or remote effect of an astringent kind. As regards the 

 bowels, the clinical applications of this action are most impor- 

 tant. Thus most of the salts of iron cause constipation unless 



