UC-NRLF > n 3c 2D2 DSfi •S I GIFT OF 8C61 'I? WP -lw A 'N; '3s JUID1 1913 The ! Intra-Uterme Growth-Cycles of the Guinea-Pig. J. Marion Read \%tt~ With 2 diagrams Sonderabdruck aus dem Archiv fur Entwicklungsmechanik der Organismen Herausgegeben von Prof. Dr. Dr. Wilh. Roux in Halle a/S. XXXV. Band, 4. Heft Ausgegeben am 4. Marz 1913 UNIVERSITY Leipzig Wilhelm Engelmann 1913 Das Archiv ffir Entwicklungsmechanik der Organismen "OVD* steht offen jeder Art von exakten Forschungen tiber die ,,Ursachen" der l Entstehung, Erhaltung und Riickbildung der organischen Gestaltungen*). Bis auf weiteres werden auch kritische Referate und zusammen- fassende Ubersichten uber andern Orts erschienene Arbeiten gleichen Zieles, sowie Titeltibersichten der beziiglichen Literatur aufgenommen. Das Archiv erscheint zur Ermoglichung rascher Veroffent- lichung in zwanglosen Heften sowohl in bezug auf den Umfang, wie auch auf die Zeit des Erscheinens ; mit etwa 40 Druckbogen wird ein Band abgeschlossen. Die Herren Mitarbeiter erhalten unentgeltlich 60 Sonderdrucke ihrer Arbeiten; eine grb'Bere Anzahl Sonderdrucke wird bei Voraus- bestellung gegen Erstattung der Herstellungskosten geliefert unter der Voraussetzung, daB die Exemplare nicht fur den Handel be- stimmt sind. Referate, Besprechungen und Autoreferate werden mit Ji 40. — fur den Druckbogen nach SchluB des Bandes honoriert. Die Zeichnungen der Textfiguren sind im Interesse der rascheren Herstellung womoglich in der zur Wiedergabe durch Zinkatzung geeigneten Weise auszufiihren**). Die Textfiguren sind vom Texte gesondert beizulegen; an den Einfugungsstellen im Texte sind die Nummern der bezuglichen Figuren anzubringen. Sind die eigentlich fur den Text bestimmten in linearer bzw. punk- tierter Manier hergestellten Figuren sehr zahlreich, so werden sie besser auf Tafeln beigegeben. Tafeln sind in der Ho he dem Format des Archivs anzupassen; fur jede Tafel ist eine Skizze uber die Verteilung der einzelnen Figuren beizufugen. Die Erklarungen der Tafel- sowie auch der Textfiguren sind auf besonderen Blattern beizufugen. Die Einsendung von Manuskripten wird an den Herausgeber erbeten. Der Herausgeber : Der Verleger : Prof. Dr. Wilh.Roux, Wilhelm Engelmann, HALLE a/S. (Deutschland) LEIPZIG. *) Den in nichtdeutscher: in englischer, italienischer oder franzo- sis'ctie'r Sprache zu druckenden Originalabhandlungen ist eine kurze Zn- sammenfassu":ng der Ergebnisse, sei es in der Sprache des Originals oder in dentscher Sprache beizufugen. **) Dies geschieht in linearer bzw. punktierterZeichnungmittiefschwarzer Tinte oder Tusche, kann aber leicht auch durch nachtragliches Uberzeichnen der Bleistiftzeichnung mit der Tuschfeder hergestellt werden. Wer jedoch im Zeichnen mit .Feder nicht geubt ist, kann die einfache Bleistiftzeichnung ein- senden, wonach sie von technischer Seite iiberzeichnet wird. Die Bezeichnungen (Buchstaben oder Ziffern) sind bloC schwach mit Bleistift einzutragen, sofern sie der Autor nicht kalligraphisch herzustellen vermag. Anweisungen fiir di;e Herstellung wissenschaftlicher Zeichnungen zu Textfiguren mit Aus- fiihrungen uber die einzelnen Herstellungsarten und Proben derselben stellt die Verlagsbuchhandlung den Herren Mitarbeitern gem unentgeltlich zur Verfugung. The Intra-Uterine Growth-Cycles of the Guinea-Pig. By J. Marion Bead. (From the Kudolph Spreckels Physiological Laboratory of the University of California.) With 2 diagrams. Eingegangen am 5. November 1912. Archly f. Entwicklungsmechanik. XXIV. The idea was expressed by LOEB *) in 1906 that some of the phenomena acompanying the early stages of development suggest 'that gr.o/w-i^ .tpayl be determined by an autocatalysed chemical reaction. He,, is jnclined to. believe that cell division in the developing egg ceases wBen: jfo-.^'atio of nuclear to cytoplasmic material reaches a certain limit, and expresses the belief that »This ratio is determined by the laws of mass action and equilibrium «. Following up this idea, ROBERTSON 2) and OSTWALDS) published almost simultaneously in 1908 their investigations showing the great similarity between growth curves and the curves expressing the relationship between time and amount of transformation in a monomolecular autocatalytic reaction. The work of numerous investigators has rendered available a large amount of data upon the growth of plants and animals of various species. Especially accurate data upon the growth of man have been accumulated by the British Association Anthropometric Committee and by QUETELET in Belgium. It was these data in ad- dition to those published by DONALDSON4) upon the growth of rats which ROBERTSON5) chiefly utilized in illustrating his thesis. *) J. LOEB, >Dynamics of Living Matter.* New York 1906. p. 56 et seq. 2) T. B. ROBERTSON, Arch. f. Entw.-Mech. Bd. 25. 1908. 3) Wo. OSTWALD, »Uber die zeitlichen Eigenschaften der Entwicklungsvor- g'ange.* Vortrage u. Aufs. iiber Entwicklungsmech. d. Organismen, herausgeg. von WILH. Roux. Heft 5. Juli 1908. 4) DONALDSON, BOAS Memorial Volume. New York 1906. p. 5. 5) T. B. ROBERTSON, Joe. cit. The Intra-Uterme Growth-Cycles of the Guinea-Pig. 709 Mammals seem to have furnished the greatest amount of accurate information which we possess upon this subject, for it is an easy matter to weigh a mammal at birth and at stated times thereafter and thus to ascertain its increase in weight, which is the best measure of the growth of the whole organism. From information thus ob- tained, however, we get no idea of the rate of growth before birth. A curve representing this period of growth is in many respects the most important, for, if obtained, it would show the beginning of growth, the changes following upon fertilization, that is to say, the actual starting point of the reaction. OSTWALD *) published curves showing the intra-uterine growth of the human foetus. These curves were constructed from the data of His and TOLDT in which length was taken as the measure of the rate of growth. OSTWALD also showed a curve of the prenatal growth of man based upon the weights obtained by FEHLING. Such data must, of necessity, be limited in number and consequently be insufficient for generalization, although OSTWALD'S curves are remar- kably smooth. So far as I am aware, this is the only information we have concerning the intra-uterine growth of any mammal. I have observed that curves constructed from the daily weights of guinea-pigs during pregnancy were not straight but somewhat S-shaped. MiNOT2) in his exhaustive work on growth gives a table of the weight changes of pregnant guinea-pigs. The curve constructed from his data so nearly resembled the one I obtained that the possibility occur- red to me of utilizing these data for the purpose of following the course of intra-uterine growth. That the guinea-pig is particularly suited for work upon this subject is shown: 1) In that the ratio of the weight of the litter to that of the mother is very high, the average weight of a litter of three being about 225 gms. and the average weight of the adult mothers about 740 gms. These figures give a ratio of nearly 1 : 3. 2) In that the small number in the litter is an advantage, for the weight of the unit organism is considerable, even after the weight of the litter is divided by the number born. The ten cases considered herein were selected from eighteen or twenty available ones. They were chosen because they seemed to *) OSTWALD, loc. cit. 2) C. S. MINOT, Journ. of Physiol. Vol. 12. 1891. 263345 710 ^ J. Marion Read be normal m every way. As far as possible adult mothers were chosen, and so no litters consisting of only one are included J). The cases designated as Xj and Kj were first litters, however, containig three and two respectively. No cases were included in which the mother became pregnant immediately after parturition, thus nursing- one litter while carrying another. All of my animals were weighed every second day, so there is a complete record of the weights of all for the past fifteen months. Table I, column A, gives the weights of the mothers at copulation. Except in the cases noted under » remarks « the weight is that actu- ally observed, recorded within twenty- four hours before or after co- pulation. In the four cases noted under » remarks « the weight in column A was raised to an average of the weights for a week or two preceding. In most cases the weight at copulation was very close to the average weight. For the sake of comparison and as an aid to correct valuation of the results, I am publishing two tables. Table I gives the weights as they were actually recorded and Table II shows these weights again with six of them corrected as explained under > remarks «. It may be noted here while discussing the weights of adult guinea-pigs and the corrections I have deemed it advisable to make, that these animals display considerable variation in weight from day to day. In an adult guinea-pig of 650 — 850 gins, a variation of ten or twenty grams is not exceptional. MiNOT2) says, »In all the weighings there is necessarily an error ±. A positive error because the digestive tract, particularly the wide caecum, contains always considerable quantities of undigested material; moreover the bladder may hold a greater or less quantity of urine. A negative error be- cause every illness, even a very slight indisposition and every in- jury such as a bite for instance, causes a greater or less loss of weight. The quantitative value of these errors is presumably not very great; they probably counterbalance one another to a certain extent in the averages which may be accepted as approximately accurate. « Guinea-pigs are very sensitive animals and a very slight disturbance will cause considerable change in weight. At a recent weighing almost all of my animals had lost heavily due to the fact that they had been moved the day before from one animal house *) Immature mothers usually bear one in a litter. 2) C. S. MINOT, loc. cit. The Intra-Uterine Growth-Cycles of the Guinea-Pig. 711 Table I. Actual, observed weights. A Weight at copulation B Weight just before parturition B-A Increase of weight during gestation C Weights of the young ones in the litter (B-A)-C Weight due to fat placentae and growth of mother Bern arks upon revision of weights, too high or too low A2 749 940 191 64, 67, 72 — 12 B is too low, average of weights for 16 days preceding parturition is 952 g. A3 810 1042 232 69, 68, 76 29 B3 760 1030 270 67,92 111 B4 855 1110 255 80, 84, 97 -13 A is too high, average of weights for two weeks preceding co- pulation being 834 g. C4 750 1091 341 57, 82, 95 108 A is too low, average of weights for 10 days preceding copulation being 770 g. H2 542 908 366 76, 77, 79 132 A is too low, average of weights for two weeks preceding co- pulation being 579 g. Xt 560 881 321 64, 67, 70 120 Bpi 766 1090 324 72, 77, 79 96 A is too low, average of weights for two weeks preceding co- pulation bein^ 783 g. Bp2 772 1030 268 74, 75, 79 30 B is too low, average of weights for a week preceding parturition being 1055 g. K, 430 716 285 79,81 125 into another, a distance of 50 feet perhaps. The disturbance was sufficient to cause one of the animals to give birth prematurely (59 days) to a litter of three. The low weight at copulation in the four cases under conside- ration I belive to be due to the excitement and muscular work which is always attendant when a male is put into the pen with a female. The chasing is often quite severe and continues for some time. Upon many occasions I have noted a loss of weight after copulation. 712 J. Marion Eead Table II. Observed weights and weights corrected. A Weight at copulation B Weight just before parturition B-A Increase of weight during gestation C Total weight of litter (B-A)-C Weight due to fat placentae and growth of mother Remarks upon revision of weights, too high or too low A2 730 956 225 203 22 A observed (749) was too high, average for 10 days preceding was 731. A3 810 1042 232 203 29 B3' 760 1030 270 159 111 B4 834 1110 276 261 15 C4 760 1091 331 233 98 Though the average for A is 770, I believe it is a little too high and that 760 repre- sents better the weight at copulation. H2 575 908 333 234 99 X! 560 881 321 201 120 Bpi 783 1090 307 228 79 Bp2 772 1045 273 228 45 The weight parturi- tion has not been raised to the average of 1055, for reasons discussed in the text. Ki 430 715 285 160 125 In only two cases was the weight in column B corrected and in both it was raised to approach an average for a week or two preceding. It sometimes happens that the mother becomes upset somewhat before birth and eats lightly, thus gaining but little or even losing weight just before parturition. In most cases there is a steady gain up to the time of birth so in the two which suffered a loss it seemed reasonable to correct the weight. It must be under- stood that in all cases in which the weight is corrected it has never been raised or lowered to reach the average, but a weight has been chosen between the observed and averaged weight. In the third column of Table II the increase of weight during gestation is given. This is in every case greater than the total weight of the litter. The difference between these two figures (found The Intra-Uterine Growth-Cycles of the Guinea-Pig. 713 in the fifth column) represents the weight of placentae, amniotic fluid and blood lost at birth, as well as the growth of the mother. The mother's growth can be obtained separately by getting the difference between the weight at copulation and just after delivery. A figure thus obtained however, would represent two kinds of growth, namely, 1) continuous growth of the mother, and 2) fat accumulated during preg- nancy. This accumulation of fat during the period of gestation seems to be a general phenomenon and is especially to be noted in the case of the guinea-pig, the milk of which contains such a high percentage of fat1). For our purpose, we will disregard as far as we can, everything which is not growth of young in utero; this is represented by the value in the fifth column of Table II. Table III is an illustrative page of the calculations showing the figures for A2, Bp2, and Kt. The weight of the mother on every second day is placed in the first column and in the second appears the increase at each period over the weight at copulation. The last value in the second column corresponds to that in the third column of Table II. Since we are concerned here with the increase in the weight of the litter only, it becomes necessary to eliminate the growth due to placentae and fat accumulated by the mother, in short, everything not representing the growth of the litter. We have only one deter- mination upon the weight of the litter itself, that is, its weight just after birth. The difference between the weight of the litter and the total increase in the mother's weight during gestation is the value representing all increase in weight other than that of the litter. But this extra weight has accumulated along with the young in utero, so in eliminating it we must distribute it over the whole period of gestation. In order to eliminate this weight justly and to distribute it proportionally throughout the whole period, the following method has been adopted. A horizontal line was ruled off on coordinate paper. It represented by its length the number of days of gestation, each day being represented by one space on the paper. At the right end of this line a perpendicular was erected which correspon- ded in height to the value in the fifth column of Table II. Each space represented one gram. A right-angled triangle was formed when the free ends of the horizontal and perpendicular lines were joined by a straight line, which formed the hypotenuse. The distance *) J. MARION BEAD, » Observations on the suckling period in the guinea- pig. « University of Cal. publications in Zoology. Vol. 9. pp. 342, 343. 714 J. Marion Read Table III. Illustrative page of calculations, showing complete figures obtained from three of the ten litters utilized. Days after cop. A2 Weights of mother during pregnancy Increase over weight at copu- lation Corrected for weight of placentae fat and growth Bp2 Weights of mother during pregnancy Increase over weight at copu- lation Corrected for weight of placentae fat and growth Ki Weights of mother during pregnancy Increase over weight at copu- lation Corrected for weight of placentae fat and growth Three in the litter Three in the litter Two in the litter 0 730 0 0 772 0 0 430 0 0 2 730 0 776 4 3 453 23 19 4 757 27 25 785 13 11 433 3 - 4 6 757 27 25 785 13 10 449 19 8 8 760 30 27 785 13 8 455 25 10 10 747 17 14 790 18 12 456 26 9 12 755 25 21 778 6 0 463 33 13 14 781 51 47 800 28 19 480 50 26 16 785 13 3 490 60 32 18 782 52 47 800 28 17 486 56 25 20 777 47 41 792 20 8 485 55 20 22 779 49 42 820 48 35 500 70 31 24 782 52 45 880 108 93 509 79 35 26 821 49 33 511 81 33 28 788 58 50 860 88 70 512 82 30 30 813 83 74 868 96 77 617 87 32 32 826 96 86 840 68 57 519 89 28 34 846 116 106 878 106 84 36 848 118 107 886 114 90 570 140 75 38 870 140 128 895 123 98 584 154 85 40 875 145 133 930 158 132 576 145 73 42 883 163 140 913 141 114 580 160 74 44 915 185 172 927 155 127 585 165 75 46 908 178 164 924 152 123 592 162 79 48 918 188 173 956 184 153 618 178 91 60 944 214 199 1000 228 196 624 194 103 52 950 220 204 1007 235 202 629 199 103 64 960 230 213 1000 228 197 640 210 110 56 960 230 213 1020 248 212 655 225 120 58 985 255 237 1020 248 210 664 234 125 60 932 202 184 1010 238 199 668 238 126 62 940 210 191 1040 268 228 680 250 134 64 935 205 185 1040 268 226 684 254 135 66 945 215 195 1030 258 214 717 287 164 68 955 225 203 1045 273 228 715 285 160 The Intra-Uterme Growth-Cycles of the Guinea-Pig. v from the horizontal line to the hypotenuse along the ordinates, in- creases as we pass from left to right, and approach the perpendicu- lar line whose length represents the weight increase during gestation, which was due to other factors than the weight of the litter. The length of each ordinate (distance between the base and hypotenuse) represents the increase in weight which is in excess of the litter's weight on that day, just as the length of the perpendicular forming one side of the triangle represents the difference at birth between the total increase of weight during gestation and the weight of the litter. The length of every second ordinate (i. e. every second day) was obtained, and this figure subtracted from the weight for that day in the second column of Table III. The remainder obtained was set down in the third column of Table III. It represented the weight of the litter on that day, the last figure in the column being the total weight of the litter at birth. This correction was made in all ten cases. The results are tabulated in Table IV. This method of eliminating the weight of the deciduae, growth of the mother, and the accumulation of fat by the mother during the progress of gestation is undoubtedly open to criticism. It seems, however, to be the only feasible way of doing it and although there are doubtless errors involved, still the essential point which I believe that my data establish is the S-shaped form of the curve of growth in utero. Now a brief consideration of the probable effect of the above interpolation upon the form of -the empirical curve shows that the method employed, far from exaggerating this result, would tend to mask it for the following reasons. 1) It is reasonable to assume that the growth of the placentae and other foetal membranes will keep pace with the growth of the embryos and follow the same curve which would represent their growth. In assuming that the rate of growth is constant, as we have in the method of eliminating their weight, we tend to make the curve of the embryo's growth a straight line and thus straighten out any curved lines which may rightfully be a part of it. 2) What has been said regarding the deciduae may very well be true also of the fat accumulated by the mother during pregnancy. In the light of our present knowledge of hormones and the part they play in life phenomena, especially those connected with reproduction, we may well assume that this accumulation of fat is controlled by internal secretions whose amount and activity in turn are controlled by the growing embryos in utero. In eliminating this fat as if it 716 J. Marion Kead Table IV. Intra-uterine growth of ten litters and the growth of an individual represented by an average. A2 A3 B3 B4 C4 H2 Xt Bpi Bp2 K! No. of young Total weight Average weight No. in litter 3 3 2 3 3 3 3 3 3 2 0 0 0 0 0 0 0 0 0 0 0 0 0 2 17 15 34 -3 16 5 3 19 22 106 4.8 4 25 21 11 0 74 4 28 9 11 -4 25 179 7.1 6 25 3 36 12 53 11 32 10 8 25 190 7.6 8 27 7 47 8 54 28 29 3 8 10 28 221 7.9 10 14 33 51 4 60 17 49 12 9 25 249 9.8 12 21 19 30 3 37 38 31 13 22 192 8.7 14 47 10 30 11 19 40 19 26 22 202 9.2 16 24 20 58 36 38 3 32 20 211 10.5 18 47 32 43 32 55 49 48 12 17 25 28 360 12.8 20 41 30 23 27 52 36 59 7 8 20 28 303 10.8 22 42 36 43 44 35 22 13 35 31 25 301 12.0 24 45 46 28 20 37 18 25 93 35 25 347 13.9 26 45 43 62 62 63 61 25 33 33 25 427 17.1 28 50 42 49 78 64 79 55 24 70 30 28 541 19.3 30 74 71 61 48 66 69 82 44 77 32 28 624 22.4 32 86 57 76 79 74 93 103 34 57 28 28 687 24.5 34 106 66 64 109 107 119 54 84 24 709 29.5 36 107 98 103 98 98 102 103 62 90 75 28 936 33.4 38 128 101 98 158 106 114 119 45 98 85 28 1052 37.6 40 133 78 100 135 167 132 155 79 132 73 28 1164 41.5 42 140 112 117 125 158 113 157 70 114 74 28 1180 42.1 44 172 141 133 136 157 143 167 87 127 75 28 1388 47.8 46 164 131 120 156 165 170 185 96 123 79 28 1389 49.6 48 173 147 145 155 193 173 123 153 91 26 1353 52.0 50 199 154 129 188 164 177 167 124 196 103 28 1601 57.1 52 204 158 136 192 154 186 163 126 202 103 28 1627 58.1 54 213 192 150 189 145 208 160 115 197 110 28 1679 60.0 56 213 205 126 221 152 210 158 130 212 120 28 1747 62.4 58 237 180 146 220 162 218 154 165 210 125 28 1817 64.9 60 184 175 167 245 198 225 146 180 199 126 28 1845 65.8 62 191 145 159 234 184 254 173 178 228 134 28 1880 67.1 64 185 174 143 240 186 246 202 205 226 134 28 1941 69.3 66 195 179 159 256 203 237 204 203 214 164 28 2014 71.9 68 203 203 159 261 233 234 201 228 228 160 28 2110 75.4 The Intra-Uterme Growth-Cycles of the Guinea-Pig. 717 increased at a constant rate, we again tend to make the growth curve of the young more nearly resemble a straight line. 3) The hypotenuse of our triangle resembles more closely the growth curve of the mother during the gestation period, for by this time puberty is passed and the growth curve of the mother is ap- proaching an asymptote and is nearly rectilinear. A few corrections have been made by interpolation in the weights of the pregnant mothers in cases where all the animals were heavy or light due to over- or under-feeding. But this was done only when the difference exceeded twenty grams. In Table IV only 19 out of 314 figures have been thus corrected. Turning now to the consideration of the curve of intra- uterine growth thus obtained (Fig. 1) certain features of it demand careful attention. The first part of the curve representing the first four days of gestation is not significant of the growth of the fertilized ova but represents the rapid return of the mother to normal weight after the loss occasioned by chasing and copulation. The dotted line, there- fore, probably represents the correct course of growth for this period. Although the most rapid cell division and relatively the fastest rate of growth, occurs in the early cleavage stages, still such growth will not be perceptible by the means employed in obtaining this curve. So we should not expect a very rapid increase during the first eight or ten days; for implantation of the ova does not take place till seven days after fertilization1). The slight increase in weight shown may be due to the commencement of the accumulation of fat or to other physiological processes in preparation for the coming pregnancy; but this cannot be counted as growth of the litter in utero. That portion of the curve from ten to sixty days closely resem- bles other growth curves which represent one cycle of growth. It appears probable, therefore, that one cycle begins at the fertilization of the egg and ends a week or ten days before birth, at which time (or before) another cycle begins and continues on after birth. In Table V are to be found the weights and average weights for twenty days after birth of the same twenty-eight young whose growth in utero is represented by the first part of the curve. The curve constructed from the averages in Table V is added to the curve at the 68 day ordinate. There is a slight loss of weight at birth l) GROSSER, »Vergleichende Anatomic und Entwicklungsgeschichte der Eihaute und der Placenta.* Wien u. Leipzig 1909. S. 162. Archiv f. Entwicklungsmechanik. XXXV. 47 718 Crams J. Marion Read Fig.l. ~~^~ 20 30 40 50 60 70 Intra-uterine growth of the guinea-pig. (Constructed from data in Tables IV and V.) The Intra-Uterme Growth-Cycles of the Guinea-Pig. 719 Table V. Weights and average weights of the twenty-eight young under consideration, for twenty days following birth. Age in days 0 1 2 3 4 6 8 10 12 14 16 18 20 1 ! G 67 66 66 67 70 75 82 87 97 108 110 116 H 64 64 63 64 70 77 85 93 105 111 116 123 I 72 71 70 72 75 84 87 95 107 119 122 133 W 76 79 82 89 91 102 112 125 122 128 137 133 136 Aa 68 69 74 78 80 91 100 107 118 119 125 132 134 Ab 69 61 63 67 70 78 86 95 102 107 114 118 122 R 92! 96 101 101 136 144 162 168 180 182 S 67 72 79 81 114 124 135 139 160 152 Ca 95 93 96 99 102 109 Cb 57 56 61 61 67 71 84 Cc 82 ! 76 80 84 88 98 111 M 79 77 82 84 93 108 N 77 75 77 80 84 100 130 134 139 0 72 72 73 78 84 110 136 147 161 166 180 Bpa 74 74 77 84 87 Bpb 75 75 77 85 89 100 Bpc 79 79 82 90 91 V 67 63 65 68 74 79 91 102 108 127 140 142 160 K 70 66 69 71 74 80 94 106 108 127 138 138 155 L 64 60 63 66 70 77 86 95 99 ; 114 130 133 147 Ea 81. 77 83 99 107 119 123 132 144 163 Kb 79 74 81 98 106 115 117 119 132 140 Ba 80 79 86 94 Bb 84 84 Be 97 95 101 110 Hb 76 77 88 He 77 78 84 Hd 79 81 - 89 Number of obser- 28 28 22 27 18 15 16 15 15 15 14 14 8 vations Total 2110 2087 1685 2188 1459 1318 1549 1655 1755 1908 1881 1981 1177 Average 75.4 74.6 76.6 81.0 81.0 87.8 96.8 110.3 117.0 127.2 134.3 141.5 147.1 47* 720 J. Marion Read which is characteristic of almost all mammals, but the animals pick up in two or three days and the curve continues on at the same inclination as the line representing the intra- uterine growth of the last eight or ten days before birth. This fact would seem to indi- cate that the figures and curve representing the intra-uterine growth, although obtained indirectly, have some degree of accuracy. OsTWALD1) in discussing the curve showing the growth of man says, »It is worthy to note again the continuity of the weight changes during the last foetal month and the first years of life. The well known loss of weight of the new born during the first days of life is so insignificant that in comparison to the remaining Fig. 2. 30 - 20 10 Per Cent 10 20 30 40 Curve of pregnancies resulting in abortion {constructed from data in Table VI). weight changes of the development of man it scarcely needs to be considered «. It is interesting to note that, as far as we can learn from the data so far obtained, the birth of both guinea-pigs and man does not take place at the juncture of two cycles. This is especially inter- esting in the case of the guinea-pig, which is born in a very mature state2). The period of gestation is very long when we compare it with the gestation period of other rodents. This has led one in- vestigator3) to venture the belief that in some remote period in its evolution the guinea-pig was born in a less mature state, such as *) OSTWALD, loc. cit. 2) READ, loc. cit. 3) ABDERHALDEN, »Text-book of Physiological Chemistry, p. 371. New York 1908. The Intra-Uterine Growth-Cycles of the Guinea-Pig. 721 Table VI. Per cent of weight gained or lost, during the period of gestation, by five guinea-pigs which gave birth to dead, premature litters. Days after copu- lation Y 7 Born C 5 Born A 3 Born HA 1 Born K 5 Born Average per cent increase 0 2 — 5.8 5.1 0.9 3.0 — 4.4 0.0 4 2.8 — 3.0 5.7 4.4 1.3 2.7 6 0.7 — 0.2 — 3.6 0.0 -4.7 -1.5 8 0.7 4.7 -2.1 -0.8 2.9 1.1 10 1.0 4.2 0.5 1.0 0.8 1.3 12 0.0 | —1.0 2.0 -1.2 -1.6 -0.6 14 4.0 4.9 -2.9 2.1 — 0.6 1.5 16 2.5 — 2.0 -0.7 0.3 — 0.6 -0.1 18 0.5 -0.2 0.4 -7.4 — 2.2 — 1.7 20 0.0 5.1 0.3 1.9 1.2 1.7 22 3.1 — 1.3 2.7 0.1 -2.0 0.5 24 1.5 -2.0 -4.3 1.1 3.4 -0.2 26 -3.6 0.7 1.6 -1.8 2.2 -0.1 28 2.0 1.2 0.9 5.0 3.8 2.5 30 1.8 3.2 2.0 1.9 4.3 2.6 32 4.8 -0.7 -1.0 4.2 1.5 1.7 34 2.5 2.8 3.4 1.1 1.8 2.3 36 2.8 2.4 6.0 4.0 2.8 36 38 2.2 0.1 4.6 0.6 0.3 1.7 40 1.5 2.2 — 3.3 1.2 1.3 0.6 42 3.4 1.0 3.0 1.8 1.8 2.1 44 -0.1 0.7 1.4 1.0 3.0 1.2 46 1.0 2.6 3.2 -1.6 3.5 1.7 48 — 1.7 3.0 4.4 0.3 4.1 1.8 50 — 5.2 2.0 0.0 1.5 7.6 1.2 52 — 8.0 0.0 0.2 0.0 0.0 -1.6 54 0.1 -1.0 — 4.9 -4.2 — 7.3 -3.5 56 3.6 -1.6 -4.2 -53 -1.9 58 0.4 -4.3 4.6 0.9 0.4 60 1.0 — 25 -0.7 62 1.0 — 0.4 0.3 64 — 0.5 -0.5 that in which rabbits, mice, and rats are born. If such were the case, the young must have been born before 50 days, for the two cycles seem to join or overlap between 50 and 60 days. This period seems to be a critical one in the development of the foetus. In- spection of the weights of mothers which gave birth to dead young 722 J. Marion Read shows that these mothers lost weight rapidly during this period. Table VI gives the percentage of weight gained or lost every second day by five mothers who gave birth to premature, dead litters. Fig. 2 shows the curve constructed from this data. A distinct loss of weight is shown after 50 days. Whether or not this pheno- menon has any connection with growth cycles, it is impossible now to say with certainty. But it is possible that the death of the young in utero may be due to a failure of the second cycle to connect properly with the first. The fact of the death in utero at this period is undeniable and I mention it as possibly having some significance and bearing upon this and perhaps other questions of intra-uterme development. In conclusion, I may say that I realize fully the fact that the data upon which the curve has been constructed have been obtained indirectly and that more accurate data could be obtained only by the sacrifice of hundreds of animals. But as a first attempt to arrive at the truth in regard to the appearance of a curve representing the growth following fertilization, I it submit with the hope that it may serve as a starting point for further work. Summary and Conclusions. From the facts and figures set forth and discussed in this paper and from the appearance of the curve constructed from the data, it seems reasonable to conclude that: I. It is possible to obtain a curve showing the growth of em- bryos in utero by indirect means, i. e. by weighing the mother at regular intervals during pregnancy. II. In the case of guinea-pigs, one cycle begins at fertilization of the ova and ends about 60 days after. Another cycle begins a little before the end of the first cycle and continues on after birth. III. In both the guinea-pig and man birth occurs during the course of a cycle and not at or near the juncture of two cycles. IV. The human young are born before the completion of the first cycle, while the guinea-pig completes one cycle and begins a second in utero. It is quite likely that this fact accounts for the advanced state of development of the latter animal at birth. The Intra-Uterme Growth-Cycles of the Guinea-Pig. 723 Zusammenfassung, Nach den in dieser Arbeit vorgebrachten und ero'rterten Figuren und Tat- sachen und nach dem Aussehen der aus diesen Tatsachen konstruierten Kurve scheinen mir nachstehende SchluBfolgerungen erlaubt: 1) Es ist moglich, eine Kurve zu erhalten, welche das intrauterine Wachs- tum von Embryonen durch indirekte Mittel veranschaulicht, so durch regelma'Cig wiederholte Wagung der Mutter in regelma'Bigen Zwischenraumen wahrend der Schwangerschaft. 2) Fur das Meerschweinchen beginnt ein Zyklus bei der Befruchtung der Eier und endet ungefahr 60 Tage spater. Ein andrer Zyklus beginnt eine kleine Weile vor dem Ablauf des ersten Zyklus und dauert noch nach der Geburt an. 3) Sowohl beim Meerschweinchen wie beim Menschen fallt die Geburt in den Verlauf eines Zyklus und nicht in oder nahe an die gemeinsame Ablaufs- zeit zweier Zyklen. 4) Die Jungen des Menschen werden noch vor der Vollendung des ersten Zyklus geboren, wahrend das Meerschweinchen noch im Uterus einen Zyklus vollendet und einen zweiten anfangt. Es ist durchaus wahrscheinlich, daC dieser Umstand die Ursache fur das vorgeriickte Entwicklungsstadium des letzteren Tien, bei der Geburt abgibt. ((Jbersetzt y(m ^ WebImi.dt-) VERLAG VON WILHELM EN6ELMANN IN LEIPZIG Archiv fur Zellforschung hcrausgegeben von Dr. Richard Goldschmidt Professor an der Universitat Miinchen Neunter Baud, 3. Heft Hit 26 Figuren im Text und 4 Tafeln (Seite 351-484) gr. 8. M 13.— Inhalt: Jan Hirschler, Uber die Plasraastrukturen (Mitochondrien, Gol- gischer Apparat u. a.) in den Geschlechtszellen der Ascariden. (Spermato- und Ovogenese.) (Mit Tafel XX — XXI.) — Iwan Sokolow, Untersuchungen Uber die Spermatogenese bei den Arachniden. I. Uber die Spermatogenese der Skor- pione. (Mit 1 Figur ira Text und Tafel XXII— XXIII.) — Kristine Bonnevie, Uber die Struktur und Genese der Ascarichromosomen. (Mit 7 Figuren im Text.) — Emerico Luna, Sulla importanza dei condriosomi nella genesi delle mio- fibrille. (Con 18 Figure nel Testo.) — Referate. Atlas zur Entwicklungsgeschichte des menschlichen Auges von Ludwig Bach und R. Seefelder well. Professor in Marburg Privatdozent in Leipzig I. Liefernng gr. 4. S. 1—18. Mit 24 Figuren im Text und Tafel I— XV mit 15 Blatt Tafelerklarungen. M 20.— II. Liefernng gr. 4. S. 19—74. Mit 30 Figuren im Text und Tafel XYI— XXXIV mit 19 Blatt Tafelerklarungen. Jt 36.— Die III. Lleferniig (SchluB) erscheint im Laufe des Jahres 1913 Eine hervorragende, iiuGerst wertvolle Bereicherung der medizinischen Li- teratur bedeutet das vorliegende Werk, und nicht nur der Ophthalmologe, sondern jeder, der sich fur Entwicklungsgeschichte interessiert, wird den beiden Ver- fassern fur diese wohl einzig in ihrer Art dastehende Arbeit Dank wissen. Es ist ein wahrer GenuC, mit Hilfe der pracbtigen Abbildungen sich in das Stu- dium der Entwicklungsgeschichte des Menschenauges zu vertiefen. Deutsche Arzte-Zeitung. ,• •.'.'•' Inhalt des vierten Heftes. Seite HERM. JOSEPHY, Uber eine Doppelbildung bei einer Tritonenlarve. (Mit 1 Figur im Text und Tafel XIV) 539 C. M. CHILD, Certain Dynamic Factors in Experimental Reproduction and their Significance for the Problems of Reproduction and Develop- ment. (With 3 figures in text) f 598 GERHARD KAUTZSCH, Studien iiber Entwicklungsanomalien bei Ascaris. II (Mit 63 Figuren im Text und Tafel XV und XVI) 642 T. BRAILSFORD ROBERTSON, Further Explanatory Remarks Concerning the Chemical Mechanics of Cell-Division. (With 3 figures in text) ... 692 J. MARION READ, The Intra-Uterine Growth-Cycles of the Guinea-Pig. (With 2 diagrams) 708 I. IZIKSOHN, Uber die gestaltliche Anpassungsfahigkeit des Froschherzens an groCen Substanzverlust ?24 B. HANK6, tlber die Regeneration des Operculums bei Murex brandaris. (Mit Tafel XVII) ; . . 740 W. HARMS, Ubefpflanzung von Ovarien in eine fremde Art. II. Mitteilung: Versuche an Tritonen. (Mit 6 Figuren im Text und Tafel XVIII und XIX) 748 RH. ERDMANN, Referate iiber Experimente an Protisten •. 781 JENNINGS, H. S., Assortative Mating, Variability and Inheritance of Size in the Conjugation of Paramaecium 781 ZWEIBAUM, J., Conjugaison et diffe"renciation sexuelle chez les infusories. 782 WOODRUFF and BAITSELL, G. A., Rhythms in the Reproductive Activity of Infusoria 783; WOODRUFF, L. L., Evidence on the Adaption of Paramaecium to different Environments 783] WOODRUFF, L. L., and BAITSELL, G. A., The Temperature Coefficient of the Rate of Reproduction of Paramaecium aurelia. ........ 783] GRUBER, K., Biologische und experimentelle Untersuchungen an Amoeba proteus PEEBLES, FL., Regeneration and Regulation in Paramaecium caudatum ERDMANN, RH., Depression und fakultative Apogamie bei Amoeba di- ploidea _. ERDMANN, RH., Experimentelle Untersuchungen Uber den Zusammenhang von Befruchtung und Fortpflanzung bei Protozoen, besonders bei Amoeba diploidea Druck von Breitkopf & Hartel in Leipzig. 263345 UNIVERSITY OF CALIFORNIA LIBRARY