ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
497 
the laboratory series, where the vessels could be hermetically closed, 
the results were eminently satisfactory, and much like those seen in 
the testimonials of a new antiseptic; all the germs were destroyed. 
Although not obtaining absolutely perfect results in disinfecting the 
room, the value of the method was sufficiently demonstrated, for dust in 
layers of 1 cm. thick, placed in little pots at various heights in a cupboard, 
was found perfectly sterilised in 20 hours. 
Optimum Temperature for Incubation.* — Mr. Fere comes to the 
conclusion that 38° is the temperature at which the smallest number of 
abnormal developments takes place during the first few days of incubation 
of hens’ eggs. By exposing eggs to fumes of alcohol the author finds 
that injurious effects are overcome afterwards in a large percentage of 
cases if the eggs are incubated at 38° rather than any other. 
Apparatus for making Gaseous Formic Aldehyde.f — MM. R. 
Cambier and A. Brocket have constructed an apparatus for making 
gaseous formic aldehyde, the object of which is to disinfect rooms, &c., 
by diffusing therein a definite quantity of this vapour. Its construction 
is based on the incomplete oxidation of methylic alcohol in contact with 
air and incandescent platinum, CH 3 OH + O = H 2 0 -f CH 2 0. It is 
composed of a copper vessel to hold the spirit, on which are screwed 
a number of burners. Each of the burners is composed of a metal 
tube containing a cotton or asbestos wick, and is surmounted by a 
cone of platinum wirework, fixed by means of a mica ring. The 
quantity of air is regulated by a device similar to that of a Bunsen’s 
burner, and the draught kept up by a long glass chimney. 
To set the apparatus going, the level of the spirit in the burners 
must first be adjusted to 1 cm. below the upper edge of the tube, and the 
holes in the regulator closed. The platinum case is then made red-hot 
by applying a match to it, the chimney is then put on and the regulator- 
holes opened. 
The best temperature for the platinum is when it is cherry-red ; if 
the flame be too lively the spirit undergoes total conversion into H 2 0 
and C0 2 ; if too dull, CO as well as CH 2 0 is produced. It is advisable 
to avoid the production of CO, for though it is not found in quantity 
sufficient to be lethal, yet the blood-spectrum shows the characteristic 
absorption change. With eight burners 800-1000 grm. of spirit can 
be converted per hour. 
* Journ. de l’Anat., July 1894. See Amer. Natural., xxix. (1895) p. 62. 
f Ann. de Micrographie, vi. (1894) pp. 539-42 (2 figs.). 
