In parallel with the conservation industry, mortar analysis has progressed dramatically over the last 20 years.
The procedures pioneered by Ian Constantinides and others, based as so much was (and still is), on John and Nicola Ashurst's excellent have been replaced by various more sophisticated techniques.
These additional ingredients are most often the leaves of any of three compañeros, companion plants—the shrub chacruna, It is in fact the companion plant that contains the potent hallucinogen dimethyltryptamine.
But DMT, when taken orally, is inactivated by peripheral monoamine oxidase-A, an enzyme found in the lining of the stomach, whose function is precisely to oxidize molecules containing an NH ingestion—using a route other than the digestive tract, such as smoking, injection, or inhalation—which bypasses the MAO in the stomach lining.
There are three main reasons for doing this: firstly, repair materials which match the originals will provide some continuity with the past, keeping intervention to the minimum; secondly, by matching the original materials and techniques closely, the repair materials will age in a similar way as the original; and finally, modern materials and techniques introduced in past repair work have often proved to be incompatible with the original, causing accelerated deterioration of building fabric.