ZOOLOGY AND BOTANY, MICKOSCOPY, ETC. 63 



BOTANY. 



GENERAL, 



Including the Anatomy and Physiology of Seed Plants. 



Cytolog-y, 

 Including- Cell-Contents. 



Chondriome of Plants and Pig-ment-formation. — A. Guilliermond 

 {Rev. Gcncr. Bot., 1!)19, 31, 6^5^)-770, 36 pis., 36 text-figs., 1 table). 

 The author concludes his study of the physiology of the plant-cell by 

 an account of the chondriome, the origin of the chrumoplastids, and 

 the formation of xanthophyll and carotin-pigments. His conclusions 

 are based upon observations of the epidermal cells of the flowers, bracts 

 and fruits of numerous plants, but the clearest results were obtained 

 with the flowers of Iris germanica and tulip. The cytoplasm appears 

 to be a homogeneous and hyaline substance holding in suspension a 

 chondriome composed of granular mitochondrias, rod-like bodies, and 

 chondriocontes of various forms, all of which travel rapidly in the 

 cytoplasmic currents towards and away from the nucleus. The chon- 

 driocontes appear to be of a semi-fluid nature, since they are continually 

 changing their shape. In addition to the chondriome, the cytoplasm 

 also contains small fatty or lipoid granules. The mitochondrias are 

 the most fragile constituents of the chondriome, and respond rapidly to 

 alterations in conditions of pressure, temperature, compression, etc. 

 In hypotonic sohitions they swell and are transformed into vacuolar 

 structures causing the cytoplasm to have a spongy or alveolar appearance. 

 This behaviour partly explains the difficulty of observations made upon 

 fixed and stained material. In their morphological, physiological and 

 histo-chemical characters the mitochondrias of plant-cells appear to be 

 identical with tliose of animal-cells. The author has proved that 

 globules of fat, starch, and pigments of xanthophyll and carotin are 

 formed by the chondriocontes, and they themselves are ultimately trans- 

 formed into chloroplasts. During cell-decay the chondriocontes are 

 transformed into chondriomites or granular mitochondrias, but in some 

 cases they form fatty globules, which fuse and are the final constituents 

 of the dying cell. 



These results confirm those of Faure-Fremiet and other Avriters, and 

 show that the cytoplasm is a fundamental substance, probably in the 

 condition of a colloidal jelly, and that the chondriome is one of the 

 most frequent elements of the cytoplasm, and plays a predominant part 

 in elaboration of cell-contents ; they likewise prove the elaborative 

 function of the mitochondrias. The xanthophyll and carotin pigments 

 are formed either in the chondriocontes or in the chloroplasts, or by the 

 metamorphosis of the chloroplasts. The formation of the pigments is 

 usually accompanied by the appearance of starch-grains and globules of 



