PROGRESS OF MICROSCOPICAL SCIENCE. 
17 
project above the surface of the section. By teasing, they may with 
difficulty be removed. None of these spots have been observed in the 
grey matter. They are most numerous in the medulla oblongata, and 
may be found in the white matter of the spinal cord. 
4. There is another form of degeneracy, one which was found in 
the cases of acute mania. The spots are less in size ; are far more 
numerous than in the other variety (3) ; resist carmine staining ; do 
not possess the granular characteristic ; there are no spindle-shaped 
fibres of connective tissue about them ; they behave very differently 
under the micro-chemical tests applied to the other variety of spots. 
The points of resemblance are mainly in colour and apparent density. 
Neither of them have any investing membrane. 
5. A fifth variety, as large in size as the third, possesses a dense 
investing membrane, which resists carmine staining and is less 
granular than the third and fourth. It exists in the same brain with 
the fourth variety. These spots or masses of the fifth variety are 
called " colloid," because of their resemblance to such growth, and are 
found in the medulla oblongata and pons Varolii. The last three 
varieties of degenerated masses, or spots, have one feature in common, 
a well-defined edge, a clean-cut margin, easily made out. 
6. A sixth variety, common in cases of dementia, and where the 
atheromatous capillary is found, is one in which the mass passes 
insensibly into the surrounding normal tissue. This form is larger 
and less distinct than the others. It more nearly resembles normal 
brain-tissue. Sometimes these masses are lobulated. They are granular 
and dense, less numerous than in the other varieties, and do not appear 
in clusters. They appear to destroy or transform the tissues, and if 
surrounding a capillary, destroy its walls. A point of resemblance in 
common with the third variety is, that connective-tissue fibre appears 
in both. 
The condition of the cellular structures of the brain, of the nerve- 
fibres and so-called lymph-spaces, are all fields rich in results not 
here spoken of. 
The Blood-glohules of a Nemertian Worm. — The 'Academy ' (May 8) 
says that M. Marion, in a communication to the French Academy, 
describes a nemertian worm, DrepanopJiorus spectahilis, as possessing 
*' a vascular apparatus which exhibits the surprising peculiarity of 
containing elliptical, slightly flattened red globules, like those of 
human blood. Their largest diameter is 0*01 mm. . . . When a 
portion of the body of the worm is pressed, these corpuscles accumu- 
late in certain parts of the circulatory system, and form a mass of an 
intense red colour. The movements of the globules can be followed 
by viewing the animal as a transparent object. They are put in 
motion by a colourless liquid, in which they float in a constant direc- 
tion. The animal possesses a median dorsal vessel, and two lateral 
ones, situated on the ventral side. Below the nervous ganglions the 
dorsal vessel bifurcates, and anastomoses with the two lateral trunks, 
which follow the posterior margin of the superior ganglions, and are 
prolonged into a cephalic ansa. The dorsal canal gives rise to trans- 
verse ansae, regularly spaced. Each of these branches continues to 
c 2 
