482 Miscellaneous. 
According to the statements to which I have just alluded, these 
structures should be chiefly found in the frontal lobe *, where they 
ought to appear particularly abundant ; now the histological exami- 
nation of this region brings to light three kinds of nervous 
elements :— 
1. Normal nerve-cells, generally unipolar or bipolar, with a bulky 
body and a globular nucleus, the chromatic power of which varies 
according to the development of the nuclein substance. 
2. Other nerve-cells, differing from the foregoing by the existence 
of two or several nuclei. These nuclei are feebly stainable by the 
colouring reagents; the nuclein substance is here found to be fre- 
quently represented by ovoid corpuscles, as may be demonstrated by 
the aid of a good immersion objective. 
3. Little cells, measuring on an average 4 p, and possessing so 
large a nucleus that the body of the cell is frequently found to be 
reduced to a delicate peripheral layer of protoplasm. These cells 
reproduce fairly well the old type termed myelocyte. 
We observe that these various elements are distinctly cellular and 
that it is impossible to admit the existence of free cerebral nuclei. 
This conception is without doubt the result of a hasty and incom- 
plete study of the third histie form which has just been described. 
In reality wherever nuclei appear they are accompanied by a proto- 
plasmic mass, the boundaries of which, though often difficult to 
follow, are nevertheless incontestable. 
The comparative histology of the principal groups of Invertebrates 
had, moreover, established during the last few years fT the existence 
in them of elements identical with those which, in the case of 
Myriopods, have been pointed out as new and of a special character. 
It is sufficient in all these cases to multiply observations, in order 
to perceive that the pretended free nuclei become united by means 
of numerous transitional forms to the normal type of nerve-cell; 
they represent nothing but a simple variety of the latter.— Comptes 
Rendus, t. exvii. no. 5, July 31, 1893, pp. 291-293. 
* It would be necessary to formulate certain reservations with respect 
to the employment of this term and to the limits of the region which it 
serves to designate; but I have not to consider here the details apper- 
taining to the descriptive anatomy of the nervous centres in Myriopods. 
+ Joannes Chatin, “Sur les Myélocytes des Invertébrés,” Comptes 
Rendus, 1888. 
