1 52
I JON E r, p:. MAW 11 EYLE Y -THOMAS
tumour. Both ty1)c.s of trimour arc considered under the general
heading of neoplasiii. Neopliksia was initially thought to be a disease
of man, but the view is being increasingly held that, in all probability,
it is a property of life as much as rt%spirtition or reproduction. Neoplasia
is nsually of unknown aetiology but, as research has progressed, vttrioua
aetiologies have been found to bc reqonsible for neoplastic lesions.
As more netiologies arc discovered, the diagnosis of neoplasia may
disappear, since it may represent but a common response of the host to a
variety of established stimuli. Some of these established aetiologies will
be discussed later. In many instances, in the study of tumours in the
lower phyla, one can only remember the advice of the great British
neurologist, J . Hughlings Jackson ( 1 835-1911) : “ The study of the
causes of things must be preceded by the study of things caused.”
Within the classes of animals discussed in this chapter it is the discerning
observittions and the iLccuritt>e documentation of tumours which have
been attempted. In the light of today’s sophisticated research techniques this approach ma,y seem mundane. The great observations of the
past have often been tlcscribed in a detail which surprises the readers of
today. With advnnced technology the simple observation is, all too
often, never made. An interest in the past is often taken as a sign of
senility, hut the reader of any text, on pathology since Virchow (18211902) establiAhed ccllrilar pathology can appreciate that “ He who is not
disposed to read history should repeat it.”
IT. NEoPrAsrA IN MARINE INVERTEBRATES
For maliy years it was tholight that neoplasicl was the exclusive
property of thc vertebrate (Teiitschlaender, 1920) and that neoplauia
was restric$ed in the phylogenetic tree to Class Pisces and above.
Several authors have written at some length as to the reamns why
invertebrate tissue cannot undcrgo neoplastic transformation but this
view has subsequently proved to he unfounded. Of the tumourfi of
Invertebrata only a few earlier references cnn be found (see Codremu,
1939; Finkelstcin, 1944: Wautier tind Wautier, 1953) and it was not
until the 1950s that the subject of comparative pathology, in relation
to animds in general, experienced a renaissance. Scharrer and Lochhead
(1960) wrote a useful review with over 160 references to tumours in
invertebrates. The only verificbd neoplasms in marine invertebrates have
occurred in oysters and clams, and possibly one in a coral (Squires, 1965).
As early t i s 1887 Ryder desc+ribcvl it menenchymal t umour of the
perirurdiitni i r t aii oystt.r (hzs.so,Pfr.m viwyinica (C>melin, 1791). A similar
finding in the siirtw spcries was noted by Smith (1934). ‘L’hecre ticinours
were po1ypoid:rl and coiisisted of t>ypical mcsenchymal c t 4 ~
eoverecl hy
I JON E r, p:. MAW 11 EYLE Y -THOMAS
tumour. Both ty1)c.s of trimour arc considered under the general
heading of neoplasiii. Neopliksia was initially thought to be a disease
of man, but the view is being increasingly held that, in all probability,
it is a property of life as much as rt%spirtition or reproduction. Neoplasia
is nsually of unknown aetiology but, as research has progressed, vttrioua
aetiologies have been found to bc reqonsible for neoplastic lesions.
As more netiologies arc discovered, the diagnosis of neoplasia may
disappear, since it may represent but a common response of the host to a
variety of established stimuli. Some of these established aetiologies will
be discussed later. In many instances, in the study of tumours in the
lower phyla, one can only remember the advice of the great British
neurologist, J . Hughlings Jackson ( 1 835-1911) : “ The study of the
causes of things must be preceded by the study of things caused.”
Within the classes of animals discussed in this chapter it is the discerning
observittions and the iLccuritt>e documentation of tumours which have
been attempted. In the light of today’s sophisticated research techniques this approach ma,y seem mundane. The great observations of the
past have often been tlcscribed in a detail which surprises the readers of
today. With advnnced technology the simple observation is, all too
often, never made. An interest in the past is often taken as a sign of
senility, hut the reader of any text, on pathology since Virchow (18211902) establiAhed ccllrilar pathology can appreciate that “ He who is not
disposed to read history should repeat it.”
IT. NEoPrAsrA IN MARINE INVERTEBRATES
For maliy years it was tholight that neoplasicl was the exclusive
property of thc vertebrate (Teiitschlaender, 1920) and that neoplauia
was restric$ed in the phylogenetic tree to Class Pisces and above.
Several authors have written at some length as to the reamns why
invertebrate tissue cannot undcrgo neoplastic transformation but this
view has subsequently proved to he unfounded. Of the tumourfi of
Invertebrata only a few earlier references cnn be found (see Codremu,
1939; Finkelstcin, 1944: Wautier tind Wautier, 1953) and it was not
until the 1950s that the subject of comparative pathology, in relation
to animds in general, experienced a renaissance. Scharrer and Lochhead
(1960) wrote a useful review with over 160 references to tumours in
invertebrates. The only verificbd neoplasms in marine invertebrates have
occurred in oysters and clams, and possibly one in a coral (Squires, 1965).
As early t i s 1887 Ryder desc+ribcvl it menenchymal t umour of the
perirurdiitni i r t aii oystt.r (hzs.so,Pfr.m viwyinica (C>melin, 1791). A similar
finding in the siirtw spcries was noted by Smith (1934). ‘L’hecre ticinours
were po1ypoid:rl and coiisisted of t>ypical mcsenchymal c t 4 ~
eoverecl hy