2582 Journal of Applied Microscopy 



GENERAL PHYSIOLOGY. 



RAYMOND PEARL, University of Michigan. 



Books and Papers for Review should be Sent to Raymond Pearl, Zoological Laboratory, 

 University of Michigan, Ann Arbor, Mich. 



,. ^ .. .r> i. ., , , . , , In this first, very detailed and thorough 



von Linden, M. Grafin. Morphologische und ■' ° 



physiologisch-chemische Untersuchungen Contribution to a subject of great inter- 

 uber die Pigmente der Lepidopteren. Arch. ^^^ ^j^e author deals with the yellow 

 f. d. ges. PhysioL 98: 1-89, 1903. . ■' 



and red pigments of the Vanessa; (io 



and urticce). She finds that the red or reddish yellow pigment of the scales of 

 these insects is found in different modifications of color in the bodies of the 

 pupae as well as in the tissues of the caterpillars. The color tone of the pigment 

 depends on its degree of oxidation, and by changing the amount of oxygen a 

 series of color changes may be produced, as is the case with bile pigments. 

 The reduced pigment is carmine red in color, while oxidation changes it to a 

 yellow-green-gray color. In the tissues of the caterpillar the pigment is found 

 in its oxidized form. The carmine red form first arises after the pupa case has 

 hardened, practically completely shutting off the epidermis from the oxygen of 

 the air. The carmine red pigment changes within the scales themselves into its 

 yellowish red modification. The chemical rays of the sunlight act as oxidizing 

 agents, changing yellowish brown solutions to greenish grey. Heat darkens the 

 color, bringing out a red-brown tone. The Venessa pigment is capable of crys- 

 tallization, the crystals being clinorhombic plates. The crystals are very much 

 like those of haematoidin and bilirubin. The pigment has a characteristic 

 absorption spectum, much like that of urobilin. It is a proteid body, reacting 

 clearly to the Millon and xanthoproteic tests. It is easily shown to be a com- 

 bination of a proteid body with a pigment, such as we have in haemoglobin for 

 example. The proteid body is an albumose, apparently allied to the globulins. 

 The colored component of the pigment is an acid, resembling bilirubin in its 

 reactions with solvents, its crystal form, color and optical relations. Its spec- 

 trum, on the other hand, is more like that of urobilin or hydrobilirubin. The 

 red Venessa pigment contains iron and free sugar. On this account the author 

 thinks that it has some function as a reserve substance. Its principal function 

 is in respiration. The pigment is formed in the intestine from plant pigments 

 (principally chlorophyll) taken in with the food. 



The paper, though full of detail, is extremely interesting, and stands as an 

 example of the sort of investigation which must be prosecuted before we can 

 hope to get far with the problem of animal coloration. R. p. 



Prochownik, S. Ueber Widerstands- und Le- The author has made a Study of the 

 bensfahigkeit epithelialer Zellen. Zeitschi. ability of certain epithelial tissues of 

 f. Allgem. PhysioL 3: '?i-s6, 190^. , . , 1 • 1 r ^ 



mammals to withstand various harmful 



environmental exposures, and at the same remain alive and capable of regener- 

 ation. His results are very remarkable. The method of experimentation used 



