Geology and Natural History. 411 
taught rather by oe asked and by observations incited 
than by didactic lectur 
The second primer pend Nak the ser at and displays the 
method of Professor Gooda le’s course of lessons “Concerning a 
Few Common Pants,” For the first ies on a seedling, each 
* the 
child-pupil, had aah him a bean freshly soaked, another the 
sprouting of which in germination had barely commenced, a 
third with germination more advanced, a fourth which had ‘de- 
cotyledons. The discourse opens the asking of some simple 
questions, every one of which must be epee by an examina- 
om of these o objects. The second lesson compares two seedlings, 
the pea with the bean; the third somupee still other and 
different seedlings ; and b this time the upils have made out 
the leading facts and ideas of ¥ vegetable morphology as it were 
for themselves. This knowledge is extended in a similar way, an 
way in which plants feed and grow is rice : phen wood is — 
which each pupil has a set ; and the structure poe sateen ae of 
the blossom is brought o out y similar methods. Teachers so 
taught should be able to give “object — ” to their young 
pupils with some success. Those who have not the advantage of 
such training should send for these primers ome ten and twenty 
ot apiece) study them thoroughly, and follow the directions 
the 
The tt hird primer, about Commercial and other Sponges, is very 
good, but different. It begins aright with a bath sponge, and 
some common reef-sponges to be had cheaply of the wholesale 
druggists, But it departs from the normal plan bd entering into 
sponge-gathering by divers in the tae on the ad of 
preg 
Function of the Sterile — of f fetdenen- ts L& 
Rabe, in Belgium, has been investigating two allied Mexican 
artweg 
their varieties, now common in cultivation. Noting the fact 
‘that the ste terile filament, which belongs to the upper side of the 
flower, is from near its base, declined upon the lower side of the 
corolla-tube or throat, he comes to the conclusion that its princi- 
pal function is to obstruct the access of unwelcome insects to the 
nectar at the base of the flower. The size of the corolla and dis- 
position of the genitalia is such that only large insects, such as 
pphle lowe which fill the whole cavity, can effect fecundation. 
at smaller ones, which would rifle the flower of its: 
Rieacte. eehont rendering any service, are excluded from the 
nectar by this bar across the base of the tube. Professor Kerner, 
