Pani se 
1878.] Scientific News. 263 
were to stand in place of the text-book in other departments, to 
be of smaller size, and to be accompanied by pages of explana- 
tions, constituting an atlas to be studied by the scholar. The 
other kind should be of large size and be used in the school 
room like wall-maps without printed explanation. The exercises 
should be tests of proficiency of the student in the identification 
of parts in the specimens or the wall-maps, after study of the 
atlas or the object, under direction of the teacher. Instruction in 
classification following identifications of parts, were recommended 
to be conducted by the aid of simple analytical keys, either drawn 
by the teacher on the blackboard, or in chart form, like the 
diagrams of structure, suspended on the wall. The similarity be- 
tween instruction in geology and structural biology, to geography 
mind in all questions of practice or thought. In the dynamical 
sciences, or structure in motion, the use of text-books was regarded 
as necessary. ) 
— The following circular has been issued by the Pennsylvania 
Board of Agriculture, and is signed by Thos. J. Edge, Secretary. As 
an effort to obtain reliable information on an obscure subject, by 
a goverment commission, it is worthy of general attention from 
those to whom it is addressed : 
“ Harrisburg, February 1, 1878. Dear Sir :—The report of this 
Board for your district has named you as a practical dairyman, 
who would be likely to take an interest in the advancement of our 
knowledge of dairy matters, and who would also be willing to 
answer any question which may be asked, with a view of obtain- 
ing such information. If our reporter is right in his surmise, and 
you are willing thus to assist me, you will please signify the same 
on the enclosed card ; giving full name and address, with number 
of cows in your dairy,and return the card at your earliest conven- 
ience. This Department is aware that we have enough of theory, 
and are much in need of practical observation, and we think that 
by proper application of this kind of observation, you can enable 
us to render comparatively certain many items which are now in 
doubt. 
“ Of such subjects, we have selected the possibility of regulating 
the sex of calves as the first to claim your attention, and I would 
respectfully ask your careful and practical observation of the fol- 
lowing theory, for one year, and would further ask that you report 
when you have any information to warrant you in so doing, giving 
the cases in which the theory has held good, as well as those in 
which it has failed. You can also confer a favor by directing the 
attention of your farm club or grange to the matter, and also 
interest any other dairyman in your neighborhood. + 
“It has been claimed by good authority, and the claim seems 
to be supported by proof, in some cases at least, that each alter- 
= nate ovum will produce a male if impregnated at the proper 7 
