524 



Dr. Balfour showed an instrument, prepared by Messrs. Smith & 

 Beck, for making circular cells for microscopic preparations. 



The following papers were read : — 



1. ' Remarks on the Growth of the Jalap-plant {E.vogonium Purga), 

 and of the Scammony-plant {Convolvulus Scaumionia) , in the open 

 ground of the Botanic Garden ;' by Professor Balfour. After alluding 

 to the cultivation of the jalap and scammony plants in Britain, Dr. 

 Balfour read the following remarks, by Mr. M'Nab, on their growth in 

 the open air in the Botanic Garden : — " The Exogonium Purga has 

 been cultivated in the Edinburgh Botanic Garden since 1838, but 

 always in a greenhouse, or a cold, glazed pit protected from frost. 

 During the summer of 1850 a plant of Exogonium was placed in the 

 open air, in the medical department of the Garden, in soil composed 

 of loam, leaf-mould, and sand, and protected with a hand-glass for 

 six weeks. It soon commenced growing, and flowered during the 

 months of August and September of that year. In autumn, after the 

 stems had died down, some horse-manure was laid on the surface of 

 the soil, above its tuberous roots, six inches deep, and afterwards co- 

 vered with soil. This covering was allowed to remain till March, 

 1851, when the superfluous manure was removed, and the remainder 

 dug into the ground around the roots. A hand-glass was then put on, 

 and allowed to remain till June. By this time the plant was giovving 

 freely, and flowered during the months of August and September of 

 1851. The same treatment was adopted during the autumn of J 851 

 as was done during the previous autumn ; and the roots, when recently 

 examined, were found to be in a growing state. The tuberous roots 

 of Exogonium are very susceptible of frost, and require to be deeply 

 covered for protection. The under-ground stems, when cut in pieces, 

 placed in pots of sand, and plunged in bottom heat, root freely at this 

 season of the year. During the month of May, 1851, a plant of the 

 scammony was planted in the open air, in the medical department of 

 the Garden, side by side with Exogonium Purga, above described. It 

 was planted in a mixture of loam and sand, and protected with a hand- 

 glass for six weeks. When the hand-glass was removed it was allowed 

 to ramble up some small, branched sticks. It grew freely, and showed 

 numerous flower-buds, but few expanded, and these during the month 

 of September. The stems were destroyed at the same time with the 

 Exogonium, and were afterwards treated in the same way as it. The 

 roots are now quite fresh (March 10, 1852), under a hand-glass. 

 Through the kindness of Mr. Moore, of the Chelsea Botanic Garden, 

 we received, during March, 1851, a packet of scammony-secds. With 



