SCIENTIFIC SUMMARY. 
541 
conclusions are very valuable, and, as they bear upon the entire pathology 
and treatment of this class of diseases, they should be known to all 
physicians. 
Development of the Maxillary Bones. — Mr. Hulme has compiled a useful 
essay upon this subject, in which to his own inquiries he unites those of 
Rathke, Reichert, Coste, Leidy, Robin, and others. He thinks that it is evi- 
dent that each superior maxillary bone in man is derived from two distinct 
centres of development. One of these produces that portion of the bone 
which corresponds to the superior maxillary bone of the lower mammalia, 
and the other to that portion of the jaw which contains the incisor teeth and 
corresponds to the intermaxillary bone of the same animals. The develop- 
ment of the lower jaw proceeds more rapidly than that of the upper, 
for, while it is not until the thirtieth or thirty-fifth day that we find 
indications of the four buds or processes from which the superior jaw- 
bones are developed, the buds which constitute the lower jaw have grown 
out and united in the median line as early as the twenty-fifth or twenty- 
eighth day. — Vide Dental Review , April, 1864. 
Bony Tumour in the Eyelid. — In that excellent periodical the Ophthalmic 
Review , we find the following case reported from Yon Grafe’s Journal. 
A patient presented an enlargement of the upper lid, and on everting 
this a circumscribed tumour of somewhat oval form and as large as half 
a hazel-nut emerged from the palpebral sinus, not far from the outer angle. 
It was hard and covered with smooth conjunctiva. It was drawn forward 
with the forceps, and excised and examined by Dr. Schweigger, who found 
under the normal conjunctiva a very dense cellular tissue, and then a 
nucleus of true bone, somewhat resembling in form an incisor tooth, and 
measuring almost three lines in its longest diameter. 
Fatty Degeneration of the Blood . — Under this title a new disease has 
been described by Signor Tigri, who finds that the circulating fluid occa- 
sionally undergoes a peculiar alteration, which results from the accumu- 
lation of a fatty substance in the red corpuscles. This phenomenon, which 
was at first observed only in extravasated blood, has now been detected in 
the fluid traversing the vessels. Signor Tigri is of opinion that this dis- 
covery will help to explain the nature of certain cases of death in which 
no apparent alteration of the organs indispensable to life has been observed. 
— Vide Comptes Rendus , April 18th. 
Micro-photographs. — M. Duchenne, of Boulogne, has succeeded in 
obtaining some very beautiful photographs of the microscopic appearances 
of various portions of the spinal-cord of man. The specimens represent 
transverse sections of the marrow in the normal and pathologic conditions, 
and indicate magnifying powers of from 200 to 1,000 diameters. If these 
representations are sufficiently distinct to admit of their being trans- 
ferred to stone and then printed, the benefit to science w T ill be very 
great. By such means, if generally adopted, a good deal of unpleasant 
controversy would be avoided. 
Cause of the Falsetto Voice. — According to the researches of M. Fournie 
the falsetto voice is produced by the following alterations of the vocal 
cords : the two posterior thirds are kept in close contact by the action of 
the inferior and middle constrictors of the pharynx and by the contraction 
VOL. III. — NO. XII. 1 2 O 
