No abstract

A multiple-regression equation was derived in which the statistical significance of the effects of six independent variables on metabolic rate could be arranged in the following order: exposure temperature, body weight, starvation period, feeding period,

Upon comparison of results obtained from growing eight different species of anaerobic bacteria in deep agar under two and three atm of pure oxygen with results of growing them in air under atmospheric pressure, it appears possible that the old terms of "microaerophobic," "very strict anaerobe," and "microaerophilic" can be replaced by precise values corresponding to the size of the inhibition zone produced by oxygen under various pressures when the bacteria are grown in a solid medium. The simultaneous effect of the dilution of the inoculum and the pressure of oxygen used was determined with the help of an electronic computer according to the standard multiple regression method. Two indices have been worked out which express the sensitivity of the species at different oxygen pressures when varying numbers of anaerobic bacteria are used: X sp, which is the size in millimeters of the inhibition zone when 1: 10 dilutions of the culture are grown under pure oxygen at atmospheric pressure (lp = 0), and B sp, which is the result of multiplying by 1.43 the difference in size of inhibition zone when 1 :10 dilutions of the culture are grown under atmospheric air (lp =-0.7) and under pure oxygen at 1 atm absolute.

Slugs of the speriee A r i m cirnmrrrifihs were acclimated to temperatures of jn, gC, 109 20", and 25" C respectively. After acclinlation, nietabolic rate was determined, either as oxygen consumption, ac 30" and 20", or by direct dor rimetry, at 25' and 12.5". At all qiven expostkre temperatures, the average rnetaholic rate ttas lower, I y I % to 1.5?&, fur each d e~r e e of increase in the acclimation temperature. Khen the Iogarith~ns of total 0~ conslimption or heat production per hour are plottcd against the Iwarithnls of body weight. the rqression Iine obtained for slups acclimatd to heat stands lielow that ohwined for slugs acclimated to cold; the s t o p is alw slighter for the warm-admated slugs t h a n fnr the cold-acchated, so that the distance I~t w e e n correspondi~lg points of two such curves is larger in the ri~hthand side of the graph, where the, large specimens are represented, than in thc lefthand side where the sma1l specmens are shown. This would imply that a n increase i n the acclimation temperature reduces metabofir-rate to a proportionately greater extent in the larger specimens than i t does in the smaller nncs. The value of the slope, which is inversely correlated with acclimation cempemture, is also inverselv correlated with the esprinwntal temperature a t which metabolism is determind. (A) Introduction ( a ) L'ACCLIMATATION CHEZ LES POIKILOTHERMES AQUATIQUESLes ittudes ritalisites B date sur l'acclimatation thermique des poikilothermes ont portit surtout sur des organismes marins ou aquatiques. Deux effets gCnCraux ont CtC observks A la suite de sejours prolonges A des temperatures differentes: les animaux a d a p t b ou acclimatCs au froid ont un taux de mCtabolisnle plus Clev6 que les animaux adapt& ou acclimates A la chaleur, si les determinations de metabolisme sont effectuees A une m&me temperature; de plus les temperatures littales, superieure e t inferieure, sont plus basses chez les animaux adapt& ou acclimates au froid que chez les animaux adapt& ou acclimatits A la chaleur.Ces deux effets ont kt6 verifiits A trois niveaux differents. On a comparit des populations vivant dans des habitats de tempCratures moyennes differentes; les differences observkes alors dans le taux de metabolisme e t dans les temperatures letales sont dksignites, suivant la terminologie de Hart (1957)' comme une "adaptation". Les differences de rnCtabolisme ou de tempitratures letales observees d'une saison A l'autre A l'intkrieur d'une meme population constituent ce que Hart appelle "acclimatisation". Enfin, les r b u l t a t s obtenus en laboratoire, sur des groupes d'animaux provenant d'une m&me population e t qu'on a fait sitjourner B des temperatures differentes, en contrdlant les autres facteurs d u milieu, constituent, suivant la meme terminologie, une "acclimation". Nous conserverons au terme "acclimatation thermique" le sens general d'ajustement physiologique en rCponse A un sejour prolong6 A une temperature donnee: ainsi 1"'acclimation" pourrait se definir comme une acclimatation

SUMMARY A study is presented of various buffers utilized in the preparation of human lymphocytes for scanning electron microscopy. Of nineteen different buffers tested, Hanks' balanced salt solution +0·04 mol sucrose appeared most adequate for satisfactory preservation of lymphocyte surface architecture.