Guilliermond - Atkinson — 102 — Cytoplasm 



lation) which they undergo as they are altered can be observed 

 (Guilliermond, Obaton, Gautheret). 



It may be added that MiLOViDOV and Ortiz Picon have demon- 

 strated that the chondriosomes and plastids have a specific weight 

 rather like that of cytoplasm. After centrif uging, the plastids and 

 chondriosomes remain scattered throughout the cytoplasm and it is 

 only when the plastids contain starch grains that they are carried 

 with the nucleus toward one extremity of the cell (Fig. 69). 



Recent work of Famin has proved that, contrary to previous 

 opinions (PoLiCARD and Mangenot), the plastids of epidermal 

 cells of tulip petals and the chondriosomes of Saprolegnia are both 

 resistant to high temperatures. Although their visibility in living 

 form is diminished and their chromaticity with mitochondrial tech- 

 niques is lost, they are not destroyed by these high temperatures. 

 The leucoplasts and chondriosomes of epidermal cells of bulb 



scales of Allium Cepa and tulip 

 ;^ X petals behave as do the chondrio- 



^ r, _>,=-. ~>^ somes of Saprolegnia in regard to 



^ ^ ^i C^!""^ vital dyes. They stain selectively 



c:^ "y^ f:^. w^ with Janus green, methyl violet 5B, 



;^ ^ '=:z^ • -=^ Dahlia violet and a certain number 



^ "^ ^^ V^^ of dyes recently mentioned (GuiL- 



X P !^^ o'"^^ LiERMOND and Gautheret). Em- 



$ ( ;^ ^ ployed in 0.0005-0.005% solutions, 



•^ 1 -< 2^^ Janus green stains only the chon- 



g j ^ ^ driosomes and leucoplasts, giving 



^ \ "^ -"^ them a pale bluish green color in 



^ r co^ -> ^gjjg which are living and showing 



X^ \ 1 3 cytoplasmic currents. In 0.01-0.02% 



:^ -^ solution of the dye, the chondrio- 



^^ -^ somes and leucoplasts are stained 



1 ' B but in a manner clearly more ac- 



^ centuated in the former than in 



taken by a chondriocont observed for i-ii^- "^^i^v^ ^^, ^ ■^ 



half an hour. B, Epidermis of Allium the dye accumulates in all the va- 

 SiTVn'hTr! '"''" "" ' '"'"'''"* " cuoles which contain phenol com- 

 pounds (oxyflavanol and tannin 

 compounds). At higher concentrations it produces only sublethal 

 staining with vesiculation of the chondriosomes and leucoplasts, 

 resulting after a short while in the death of the cells. 



The other dyes, which for the most part are very toxic, behave 

 somewhat differently. In low concentrations (0.0002-0.0008%) 

 they stain only the leucoplasts and the chondriosomes which are 

 colored in exactly the same way. The cells remain living for a long 

 time and show very active cytoplasmic currents. In solutions of 

 0.001% and above, the dyes accumulate at the same time in the 

 vacuoles containing phenol compounds and finally stain the nucleus 

 and cytoplasm to which they give a diffuse color in cells showing 

 active cytoplasmic streaming, but in which they rapidly cause 

 death. Staining is therefore sublethal. 



