244 Rhodora [OCTOBER 
provided with very firm and easy working latches, securing the door 
in three places at once, and are believed to represent an ideal herba- 
rium case, so far as the subject is at present understood. 
Since the instalment of the metal-covered and all-metal cases, much 
fumigation has been carried on in them. Of course, the great quan- 
tity of carbon bisulphide, which it is necessary to employ in cases of 
this size (twenty-six six-inch pigeon holes each)! would render 
any room disagreeable, and it is found desirable to carry on the fumi- 
gation during the summer vacation when students are away and the 
regular staff reduced toa minimum. However, if the ideal time ever 
comes when the whole of the great collection can be thus enclosed in 
metal, only rare fumigations will be necessary and these can be 
accomplished with the least possible difficulty. 
The use of rubber buffers in closing a can employed for carbon 
bisulphide fumigation may be a surprise to those who recollect that 
this agent is a solvent for rubber. Experience, however, shows that 
the vapor of the sulphide exercises no appreciable injury to the 
rubber, which remains soft and pliant for a longer time than would 
be supposed. 
The odor of carbon bisulphide, notwithstanding all the precautions 
which could be employed, being a great annoyance, experiments were 
undertaken with formaldehyde. In these Professor Charles Harring- 
ton of the Harvard Medical School, well known as an expert on the 
subject of disinfectants, was consulted and obligingly gave counsel 
and aid. ‘The fumigation was carried on in one of the tin tanks with 
a capacity of about fifteen cubic feet, provided with a tin door closing 
against a soft rubber strip, thus essentially air-tight. The formalde- 
hyde was produced first by the incomplete combustion of wood alco- 
hol, then, in subsequent experiments, by volatilizing with an alcohol 
lamp the well known pastilles commonly used in disinfecting. The 
quantity of vapor produced in each manner was far in excess of the 
amount which experiment has shown ample to destroy disease germs. 
Owing to the successful work of the carbon bisulphide method, which 
had been in use many months, it was found impossible to obtain in the 
Gray Herbarium any living specimens of the “herbarium beetle" on 
which to try the effects of the formaldehyde fumigation, and aphides 
from the greenhouses were used instead. The surprising result was 
' About two pounds in each case. 
