28 SUMMARY OP CURRENT RESEARCHES RELATING TO 



M. Eenaut finds that the white corpuscles of mammals generally, 

 and of man in a state of health, all closely resemble each other, and 

 are of the ordinary kind ; but in disease, as in leucocythsemia, the 

 white corpuscles are not only greatly increased in number, but vary 

 considerably in size. Moreover, they are round, and present no 

 pseudopodia. They are hyaline, and have a smooth, well-defined 

 limiting membrane, and some of them have nuclei which have under- 

 gone fission, just as in a cell that is about to segment. Hence, he is 

 of the opinion that the white corpuscles multiply and increase in 

 number while floating in the blood ; other corpuscles may be 

 observed, which are charged with granules of some proteid substance, 

 resembling vitelline granules, or small masses of haemoglobin ; and, 

 lastly, there are still other cells, which are charged with fat. M. 

 Eenaut has made some observations on the development of the 

 red corpuscles of the Lamprey, and gives the following succession of 

 forms. White corpuscle with nucleus proliferating and protoplasm 

 not limited by an exoplasmic layer ; corpuscle with nucleus prolifer- 

 ating, the protoplasm forming an uncoloured disk, limited by an 

 exoplasm ; corpuscle with proliferating nucleus, protoplasm limited 

 by an exoplasm, and forming a disk, more or less charged with 

 hemoglobin ; red corpuscle with proliferating nucleus ; and finally, 

 circular red corpuscle, with rounded nucleus. 



Nerve-endings of Tactile Corpuscles.* — W. Krause discusses the 

 different views which have been held as to the condition of these 

 nerve-endings, viz. : — (1) Langerhaus, who considers that the fibres 

 divide di- or trichotomously after entering the corpuscle, and end 

 thus by only two or three terminal twigs which may be flattened 

 into terminal disks, as is generally the case in the end-bulbs, and 

 especially in the round ones. (2) Ranvier, who states of the laminar 

 terminal corpuscles of the tongue of water-birds, &c., and of the 

 laminar tactile corpuscles, that a terminal disk is interpolated 

 between every two of the cells which lie transversely in the bulbs. 

 Krause obtained similar results by the use of formic acid and chloride 

 of gold. (3) Meissner, from pathological and other observations, has 

 set down all the transverse striation to nervous structures, except 

 some possibly due to nuclei. But Krause, supported by Fischer and 

 Flemming, has explained the large number of transverse nervous 

 terminal fibres as due to a spiral course of the latter, accompanied by 

 repeated dichotomous branching. 



In order to reconcile the three views, it may be held that 

 Langerhaus' opinion applies to some of the smallest and simplest 

 corpuscles ; while Eanvier's apply to their larger and more usual 

 forms ; whereas Fischer's preparations show the course taken by 

 the terminal fibres in reaching their disks. Krause himself holds 

 the inner bulbs to consist of transverse bulb-cells with pale terminal 

 nerve-fibres ending in knobbed or discoid terminations between 

 them. 



* Arch. mikr. Anat., XX. (18S1) p. 215(1 p].); and Biolog. Centralblatt, i. 

 (1881) pp. 462-3. 



