ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
451 
describes some intracellular parasites from the intestines of the spotted 
newt and the lake lizard ( Necturus ). Next are described some chromato- 
phagous and other intracellular parasites in the intestine of Necturus 
lateralis. There is a critical study of observations on certain structures 
in the pancreatic cells of Amphibia, and certain more purely physio- 
logical deductions. 
Indirect Fragmentation.* * * § — Dr. E. Goppert finds in the lymphatic 
cortical sheatb of the liver of Salamandra and Triton distinct evidence of 
nuclear division by a process of indirect fragmentation similar to that 
described by Arnold. At first the nucleus exhibits a distinct mesh- 
work of chromatin ; a perforation appears, around which the chromatin 
forms a ring ; the ring becomes divided into two to eight fragments 
generally different from one another in form and size, but still disposed 
in a circle ; during the whole process the nucleus remains surrounded 
by its membrane ; no associated cell-division was observed. 
History of Blood-corpuscles.*]- — Herr H. F. Muller has studied this 
both in cold-blooded and warm-blooded Vertebrates. He finds that 
the leucocytes and the erythrocytes originate from similar mother- 
cells. These mother-cells exhibit indirect division, and their daughter- 
cells undergo various modifications: — (1) Some become erythrocytes; 
(2) others are subject to further karyokinesis, but eventually form 
erythrocytes ; (3) others form mononuclear resting leucocytes which grow 
into resting mother-cells ready to divide ; (4) others seem to become 
the ordinary polymorphic leucocytes. Karyokinesis prevails in the 
formation of both erythrocytes and leucocytes, but the occurrence of 
other modes of division must be admitted. 
Origin of the Fibrillse in Connective Tissue.:]: — Herr B. Lwoff has 
investigated the connective tissue in various parts of sheep embryos. He 
agrees with Schwann and Boll in concluding that from each cell a por- 
tion of the fibril-bundle is formed, and with Rollett in maintaining that 
the fibrils appear on the surface of the cells. But he has furthermore 
observed that the formative cells are disposed in long rows and are 
connected by their processes, and that the fibrils are formed super- 
ficially along these rows. The formation of the fibrils proceeds from 
the surface inwards ; from each row of cells arises a fibril-bundle, in 
the middle of which are the remains of the formative cells. In origin 
these connective tissue fibrils are comparable to those of muscle and to 
those on the cortex of hairs and feathers. 
y. General. 
Elementary Biology. § — Prof. T. Jeffery Parker, formerly one of the 
Associate Editors of this Journal, has published what is certainly a very 
readable and will probably be found a very useful introduction to the 
study of Biology. The author hopes that his work may also be useful 
“ to that large class of workers whose services to English science often 
receive but scant recognition — J mean amateur microscopists.” 
* Arch. f. Mikr. Anat., xxxvii. (1891) pp. 375-91 (1 pi.), 
f SB. K. Akad. Wiss. Wien, xcviii. (1889) pp. 219-94 (5 pis.). 
x T. c., pp. 184-210 (2 pis.). 
§ ‘ Lessons in Elementary Biology,’ London, 1891, 8vo, 408 pp- and 89 figs. 
