ALEXANDER NECKAM. 135 



Similar notions persisted among the metallurgists until 

 the beginning of the i8th century. Thus the ready com- 

 bination of metals with mercury to form amalgams was 

 regarded as proof of mutual benignant regard, and the 

 combination of metals in their alloys was similarly ex- 

 plained, lyead is loved by gold and silver, but brass ab- 

 hors lead. 1 The astrologers claimed that metals exercised 

 a selection in benevolently mixing with various parts of 

 the human body, the gold seeking the heart; silver, the 

 brain; lead, the spleen; mercury, the lungs; tin, the liver, 

 and so on. But to living beings as units, they thought 

 that metals manifested great contrariety, because, as it was 

 gravely pointed out, no animal could subsist on metals, 

 plants do not flourish where metallic veins abound, and in 

 mines the vapors are deadly. Even in preparing pearls as 

 medicine, they must be brayed in marble mortars, because 

 otherwise iron might thus be imported into the body and 

 act malevolently. 



Neckam follows these ideas closely. Some things, he 

 says, are drawn naturally, others by accident, and when 

 by accident, either from necessity or chance similitude; 

 from necessity, as when the body, through hunger, attracts 

 so that its famishing members will thrive on insufficient 

 food, such as bran (there were evidently dyspeptics in 

 those days)/ or even on noxious herbs. Accidental simil- 

 itude occurs when non-nourishing things are combined 

 with nutriment. Natural attraction takes place, we are 

 told, in many ways, <l as by the power of heat, or by a vir- 

 tue, or by the natural quality of similitude, or by the law 

 of vacuity." Fire, for example, by the strength of heat 

 draws oil for its nutriment. 



The concept of an " attractive" virtue is the mediaeval 

 modification of Galen's selective vital force. This attrac- 

 tion by virtue, says Neckam, is caused in two ways, either 

 occultly or manifestly. Occult virtue is closely allied to 

 similitude in its effects, and acts as scammony draws bile 



1 Aldrovandus: Musaeum Metallicum, ii. 



