1208 Journal of Applied Microscopy 



also micro-chemical reactions. Many fixing fluids were employed, but the best 

 results were obtained with picric acid and corrosive sublimate. The staining 

 reagents employed were Ehrlich's and Delafield's haematoxylin, Czokor's alum, 

 cochineal, safranin, eosin, picro-carmin and methylen blue. Picro-carmin was 

 employed to stain the cyanophycin granules. A strong solution of hydrogen 

 peroxide containing traces of sulphuric acid was used to liberate the " marked " 

 iron. 



The paper is a most valuable addition to the literature of this important 

 problem. A. A. Lawson. 



Chicago. 



Pierce, 0. J. The nature of the association of Both cultures and microtome sections 

 Alga and Fungus in Lichens. Proc. Calif. ^gj.g ^gg^ j^ ^j^jg ^Q^k Various fixing 

 Acad. Sci. Ser. Ill, I: 207-240, pi. 41, 1899. ° 



agents were used, but a saturated solu- 

 tion of corrosive sublimate in 35 per cent, alcohol just below the boiling point 

 proved most satisfactory. Dehydration must be thorough, but, on account of 

 the gelatinous coating of the lichen, must not be too rapid. 



The results show that the hyphae and gonidia are in the most intimate con- 

 nection, the hyphae developing branches which clasp the algal cell or even enter 

 it as haustoria. This relation stimulates the algal cell to internal cell divisions. 

 The haustoria drain the living contents of the algal cells, leaving only the empty 

 cell walls. The fungus is fed by the alga and it is doubtful whether the alga 

 receives any benefit, since it is known that in their resting forms free algse with- 

 stand extremes of heat, dryness, etc., as successfully as do the algae which are 

 associated with fungi in lichens. c. j. c. 



CYTOLOGY, EMBRYOLOGY, 



AND 



MICROSCOPICAL METHODS. 



Agnes M. Claypole. 



Separates of papers and books on animal biology should be sent for review to 



Agnes M. Claypole, Sage College, 



Ithaca, N. Y. 



CURRENT LITERATURE. 



Beard, J. The Source of Leucocytes and the The function of this obscure gland has 

 True Function of the Thymus. Anat. Anz. ^^g^ hitherto but little known. Its 

 lo: 550-573, 1900. 



origin from the epithelium of the gill 



pouch by Koelliker for mammals, and his subsequent statement that the original 

 epithelial cells gave rise to leucocytes, has been followed by two views : one that 

 these leucocytes have migrated into the gland from outside, the other that they 

 originated within the gland. A complete developmental study of ScylUnm 

 canicula made by the author disclosed the fact that for a relatively long period 

 the blood contains only nucleated red corpuscles, no leucocytes of any kind 

 being present, as had been noted by Koelliker some years before. In these 

 studies investigation was carried on in two lines. First, a careful search was 



