ν 
138 REPORT—1850. 
In proof of the influence of a town habitation in advancing slightly the period of 
first menstruation, Dr. Tilt quotes the results of M. Brierre de Boismont’s careful in- 
vestigation of the question, results which have since been confirmed by the statistical 
information obtained in Denmark by Dr. Rawn, as well as by Dr, Tilt’s more recent 
investigations in London, 
The author maintains that the influence of civilization stands second only to that 
of climate, and he founds this belief on his own unpublished observations, and on those 
already made public by M. Brierre de Boismont and Dr. Rawn, proving that luxurious 
living and habits render menstruation precocious, while this function is retarded by 
out-door labour and less sophisticated habits. 
Thus far the tendency of Dr. Tilt’s observations has been dogmatical; but in dis- 
cussing what he calls the intrinsic causes which have been supposed to influence 
menstruation, his observations are rather of a suggestive character, for he considers 
such causes highly problematical and requiring further investigation. 
Remarks on the Laws regulating the Development of Monstrosities, with 
illustrative Specimens. By AuexanverR Woop, M.D., F.R.C.P. 
The paper first pointed out the importance of the study of teratology, in reference 
to philosophical anatomy, embryology, and natural history. It next adverted to the 
unity of type which exists throughout the whole of organized nature, and showed the 
use that had been made of that fact in laying down the laws of monstrous development. 
_ The first law adverted to was that of anomalies from excess, of which examples in 
supernumerary fingers and toes were shown. The hereditary nature of these-redun- 
dancies was adverted to, and it was argued from that, that there must be some original 
difference either in the spermatozoa or ovum, and that all the varieties of monstrosity 
could not be referred to changes taking place in the womb subsequent to impregnation. 
As examples of the second class, or those in which development was arrested, a case 
was shown in which the fingers were entirely deficient; also another specimen, 
where arrest of the development of the left inferior extremity was accompanied with 
eventration. From the concurrence of these two monstrous states, it was argued 
that in this case the arrest of development must have taken place about the com- 
mencement of the third month of uterine life. Another specimen of escape of the 
viscera from their cavities was shown in a cast of an encephalocele. 
The last specimen exhibited was one of thlipsencephalus. The posterior bones of 
the skull were deficient, the brain existed in the most rudimentary state, its place 
being supplied by a vascular humour protruding externally, composed of hypertrophied 
pia mater, a congeries of blood-vessels, and a little watery fluid. 
The paper concluded by arguing at some length against the tendency which at 
present existed to carry the theory of unity of type to an undue length. It eontended 
against there being any real resemblance between the nervous system of the Articulata 
and that of anencephalous monsters. 
A General View of the Morphology of the Muscular System. 
By M. Zaeuas. 
Comparative myology having already been sufficiently treated in the way of ap- 
proaching the ultimate forms of the muscular masses of animals to one another, for 
finding their analogies in the same animal, as well as in the whole department of ver- 
tebrata, so as to allow almost no hope of thus coming to an insight of the connexions of 
this system extending to remote classes, recourse has been had to comparative osteo- 
logy, and myology has been based on the osteogenesis. This way of treating myo- 
logy, Prof. John Miiller first indicated in his classical elaboration of the monography 
on myvinoids, Still comparative myology remains in a very unsatisfactory state. 
While occupying myself with dissections and thinking on the matter, I became strongly 
impressed by the idea that muscles must have, as well as other systems, their own 
morphological truths, and there must be a series of modifications in the muscular masses 
themselves, presented by the first appearances of a simple or elementary muscle, pro- 
vided a generality of plan in their arrangement be existing. Such a series of modi- 
fications, connecting the simplest element with the most complicated, has been pre- 
sumed to be probably the fittest means; if not the only, of reducing into one conception 
