43G Dr. C. A. MacMunn. On the Gastric Gland of Mollusca 



(2) That by the use of appropriate means these intracellular bodies 

 can be isolated and cultivated outside the body. 



(3) That these cultures, when introduced into certain animals, can 

 cause death, with the production of tumours, so far of endothelial 

 origin ; and that pure cultures can be made from these growths which, 

 when inoculated into suitable animals, will produce similar tumours. 



" On the Gastric Gland of Mollusca and Decapod Crustacea : its 

 Structure and Functions." By C. A. MAcMuNX, M.A., 

 M.D. Communicated by Dr. M. FOSTER, Sec. E.S. Eeceived 

 February 23, Eead March 9, 1899. 



(Abstract.) 



In 1883 I communicated a paper* to the Eoyal Society, in which I 

 described the occurrence of a pigment closely resembling vegetable 

 chlorophyll in the so-called liver of Invertebrates, and in 1885 a further 

 contribution in continuation of the same subject, which was published 

 in the 'Philosophical Transactions' (Part I, 1886). 



I named this colouring matter " enterochlorophyll," because after 

 comparing it with all the animal pigments and plant pigments known 

 to me, it seemed to resemble, both in its chemical and spectroscopic 

 characters, the chlorophyll of plants. 



In the latter paper, I endeavoured to describe the microscopic cha- 

 racters of this pigment, as it was found in the digestive gland, and I 

 applied all the tests then considered to be distinctive of chlorophyll to 

 the solutions of the pigment. I found that whereas enterochlorophyll 

 appeared to be a chlorophyll, or a modified chlorophyll, it yet differed 

 in some respects from chlorophyll, as it is obtained directly from fresh 

 green leaves. Some recent writers have called in question the right to 

 call this pigment by the above name, so I have reinvestigated the 

 whole subject. 



It was, however, necessary first of all to study the histology of the 

 cligestive gland, or gastric gland, as it is now named, and the micro- 

 scopic characters of the pigment found in it. This has been done by 

 Max Weber and Frenzel for the gland of Crustacea, and by Barfurth 

 and by Frenzel for the gland of mollusca.f 



As can be gleaned from these observers, great difficulties attend the 

 'preparation of this gland for microscopic observation. I found after 

 numerous failures that formol is the best fixative, used in stronger 

 solution than it usually is employed in vertebrate histology. Thus it 

 is necessary to employ solutions containing from 20 to 30 per cent, of 



* 'Koy. Soc. Proc.,' vol. 33 (L883), p. 370. 

 f References are given in the complete paper. 



