PHYSICS OF STREAMING 



It is interesting to notice that cellulose, starch, gum-arabic, glucose, and 

 cane sugar form a series of substances with progressively decreasing 

 magnetic permeability, and the same applies to the series, serum-albumin, 

 egg-albumin, keratin, gelatin, haemoglobin, fibrin, myosin. 



Chlorophyll, which contains no iron, is paramagnetic, whereas haemo- 

 globin, which contains 0-4 per cent, by weight of iron, is diamagnetic. 

 The oxides, and all ordinary salts of iron, are paramagnetic in air (Fe C1 2 , 

 Fe 2 C1 6 , Fe 2 SO 4 , Fe, 3 SO 4 , Fe CO 3 , Fe 3 PO 4 , Fe 3 NO 3 , Fe 43 (Fe C 6 N 6 ), 

 whereas salts containing the iron in the form of an acid (K 4 Fe C 6 N 6 : 

 K 3 FeC 6 N 6 ) are diamagnetic. Hence the iron of haemoglobin is not 

 present in basic form, but occurs in the form of an electro-negative radicle 

 as in the above cyanogen compounds. Under the action of acids and 

 alkalies haemoglobin readily splits up into haematin and an albuminous 

 substance. Now Gamgee has recently shown that haematin is paramag- 

 netic, and hence, apparently, contains the iron in basic form, and if the 

 albumin derivative is also paramagnetic (see previous table), we have the 

 curious circumstance of a diamagnetic substance being resolved (in the 

 presence of oxygen) into two paramagnetic ones. Plants, as a whole, are 

 paramagnetic, and this applies even to parts rendered chlorotic by growth 

 in a culture-solution free from iron, but tissues rich in water and with little 

 cellulose, leaves packed with starch, and etiolated leaves in some cases 

 (onions, &c.) may be feebly diamagnetic, but are always paramagnetic when 

 dried. Faraday's hasty, incorrect generalization was probably the result of 

 examining parts of plants which were in an abnormal condition. This is, 

 however, of little importance, as compared with the fact that plants con- 



1 Leaves were dropped in boiling water, triturated, treated with cold (i) ether, 2) 50 per cent, 

 alcohol, (3) 75 per cent, alcohol, and then extracted with warm absolute alcohol, filtered in darkness, 

 the filtrate being evaporated to dryness on a water bath. This residue (a) was then extracted with 

 ether to remove fats and oils (c) and the residue () again dried and tested. 



